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Study of Sludge Management Alternatives For Seven Counties in the Hudson Valley COASTAt ZONE INFORMATION CENTER October 31 1986 HD New York State Environmental Facilities Corporation 4479 50 Wolf Road, Albany, NY 12205 (518) 457-410.0 N7 -N49 1986 He Chairman Terence P. Curran, P.E., Executive Director ;0 STUDY OF SLUDGE MANAGEMENT ALTERNATIVES FOR SEVEN COUNTIES IN THE HUDSON VALLEY NEW YORK STATE ENVIRONMENTAL FACILITIES CORPORATION October 31, 1986 COASTAL ZONE INFORMATION CENTER Henry G. Williams, Chairman Terence P.Curran, P.E., Executive-Director U. S. DEPARTMENT OF COMMERCE NOAA COASTAL SERVICES CENTER 2234 SOUTH HOBSON AVENUE CHARLESTON, SC 29405-2413 STUDY OF SLUDGE MANAGE14ENT ALTERNATIVES FOR SEVEN COUNTIES IN THE HUDSON VALLEY Prepared by: New York State Environmental Facilities-Corporation 50 Wolf@Road Albany, New York 12205 Prepared for: Dutchess,County, Orange County, Putnam County, Rockland-County,-Suilivan-,Count-y, Ulster County, .Westchester County EFC Project Staff: Terence P. Curran,.P.E.,-Executive Director Kenneth F. Malcolm,-.-Project Manager Diana M. Hinchcliff,'Project Coordinator and Editor .Special Assistance From: 'Pickett T. Simpson, P.E. Peter A. Marini, P.E. 'Marian J.-,Mudar J. Andrea-Estus @Mary-Johnson Blass 'Donna Melcher .Funded by: The-Seven-Counties.-through.-the.Hudson-Valley Regional York--State Department@of-State Partially funded by a grant from the Office of Ocean and Coastal Resource Management, National Oceanic and Atmospheric Administration October 31, 1986 New York State Environmental Facilities Corporation 50 Wolf Road. Albany, N-Y. 12205 (518) 457-4100 Henry G. Williams Chairman 1AA Terence P. Cuffan. P.E. Executive Director October 31, 1986 TO: Members of the Hudson Valley Regional Council: The Honorable Albert A. Favoino, Orange County, Chairman The Honorable David D. Bruen, Putnam County The Honorable James Gorman, Sullivan County The Honorable John T. Grant, Rockland County The Honorable Louis Heimbach, Orange County The Honorable Richard B. Mathews, Ulster County The Honorable Andrew P. O'Rourke, Westchester County The Honorable Lucille Pattison, Dutchess County In accordance with contract No. D002960, I am pleased to provide you with this study of sludge management alternatives for the counties of Dutchess, Orange, Putnam, Rockland,.Sullivan, Ulster and Westchester. A number of comments were received on the draft report, after a series of public hearings held by the counties. These comments have either been incorporated into this final version or appended in Section 8. 0 I would like to express my appreciation to the counties, the Hudson Valley Regional Council and the New York State Department of State for providing the funding for EFC to complete this very important study. I hope it will lead to a permanent, long-term effort to resolve the counties' sludge management problems through cooperative action. rran, P.E. Executive Director @TLerence @P. Cu BOARD OF DIRECTORS NEW YORK STATE ENVIRONMENTAL FACILITIES CORPORATION Directors Henry G. Williams (Chairman and C.E.O.) Commissioner New York State Department of Environmental Conservation David Axelrod, M.D. Commissioner New York State Department of Health Gail S. Shaffer Secretary of State New York State Department of State Joseph A. Cimino, M.D. Professor and Chairman Department of Community and Preventive Medicine Martin S. Baker, Esq. Rosenman Colin Freund Lewis &.Cohen TABLE OF CONTENTS Page Letter of Transmittal Suimmary SECTION 1. INTRODUCTION Background Sludge Management'in the Last Decade Description of this Study Scope of Work EFC and NYSDEC Project Staff Technical Task Group Task Group Activities SECTION 2. DATA COLLECTION AND ANALYSIS 7 Introduction Difficulties with Collecting Data Verification of Sludge Quantities Sludge,Management Inventory 11 Municipal Sludge Solids Concentration Methods of Sludge Dewatering Methods of Sludge Stabilization Methods of Disposing of Sludge Sludge Quality Size of Treatment Plants in the Region Treatment Processes Used by STPs Industrial Flow to Treatment Plants Septage Hauler Inventory Septage Generation Methods of Septage Disposal Sludge and Septage Disposal Sites and Practices 22 Inventory Methods of Sludge and Septage Disposal by County Population:Projections and,[email protected] 30 SECTION 3. TECHNICAL ALTERNATIVES FOR SLUDGE MANAGEMENT 33 0 Introduction Sanitary Landfill .33 Requirements for Disposing of Sludge in a Landfill Estimating the Cost of a Landfill for Sludge 0 Disposal Page Composting 36 Introduction Requirements of the Composting Process Composting Systems Potential Uses of Compost Safety and Health Aspects of Composting Composting Facilities: Case Studies Costs of Composting Summary Land Application 60 Introduction Application Methods Dual Utilization Sludge Storage with Dual Utilization Review of Recent USEPA-sponsored Studies Potential for Implementation of Land Application in the Seven County Region Recommendations for All Counties Ocean Disposal 72 Introduction Process Safety and Health Considerations Additional Considerations Case Studies of Ocean Disposal Thermal Reduction 80 Introduction Incineration Multiple Hearth Furnace Fluidized Bed Incinerator Rotary Kiln Furnace Co-Incineration of Sewage Sludge and Municipal Refuse Pyrolysis and Starved Air Combustion Sludge Characteristics and Thermal Reduction Advantages and Disadvantages of Thermal Reduction Heat Treatment Flash Dryers Spray Dryers Rotary Dryers Page Indirect Heat Dryers Toroidal Dryer Oil Immersion (Carver-Greenfield Process) Solvent Extraction Dehydration (B.E.S.T. System) Thermal Reduction Case Studies: Carver- Greenfield Process and Incineration Summary Considerations,Common to Technical Alternatives 131 Introduction Sludge Dewatering Centrifuge Experience with Centrifuges Belt Press Plate and Frame Filter Press Air Drying Vacuum Filter Comparison of Dewatering Processes Conclusions Dewatering and Technical Alternatives Transporting Sludge Methods of Transport Truck Transport Transport by Pipeline Barge Transport Rail Transport Cost Considerations for All Methods Transfer Stations Environmental Impacts of Transportation 'Comparison of Costs for Sludge Management 157 Alternatives Other Wastestreams-Generated.-During,the Sewage 159 .Treatment-Process Grit Floatable Solids Screenings Industrial Wastes Review of Previous County:Engineering Reports 162 'Recommending TechnicalAlternatives SECTION 4. CURRENT REGULATIONS AND REGULATORY TRENDS RELATED 172 TO SLUDGE MANAGEMENT Land Application 172 Land Application Moratorium Page Sludge Composition Heavy Metals and Toxic Organics Pathogens Miscellaenous Factors Site Considerations Management Considerations Methods of Operation Land Application Program Approval Storage Regulations Landfill 180 Present Situation Future Policy Composting 181 Present Situation Future Policy Ocean Disposal 184 Present Situation Future Policy incineration 185 Present Situation Future Policy SECTION 5. SITING SLUDGE MANAGEMENT FACILITIES -194 Acquiring Land Cost of Acquiring Land Facility Siting Criteria Size of Sludge Facilities Site Selection Process Siting a Landfill for the Ash Residue from Incineration Host Community Incentives Potential Sites SECTION 6. DEVELOPING, FINANCING AND IMPLEMENTING SLUDGE 213 MANAGEMENT PROGRAMS Introduction Procuring Services:for Sludge,Management-Projects 213 Procurement Guidelines Bidding Procedures Procurement Alternatives Institutional Mechanisms for Sludge.Management 216 .Projects 'Introduction Available Mechanisms LIST OF APPENDICES APPENDIX A SCOPE OF WORK APPENDIX B DETERMINING SLUDGE QUANTITIES APPENDIX C IN-VESSEL C014POSTING SYSTEM SUPPLIERS APPENDIX D SAFETY AND HEALTH ASPECTS OF C014POSTING APPENDIX E CALCULATIONS FOR COSTS TO IMPLEMENT SLUDGE MANAGEMENT OPTIONS APPENDIX F A PROCESS TO SIGNIFICANTLY REDUCE PATHOGENS APPENDIX G DECISION OF THE COMMISSIONER (LAND APPLICATION) APPENDIX H. STANDARDS OF PERFORMANCE FOR SEWAGE TREAT14ENT PLANTS (FEDERAL REGULATIONS) APPENDIX I STANDARDS OF PERFORMANCE FOR INCINERATORS (FEDERAL REGULATIONS) APPENDIX J NATIONAL EMISSION STANDARD FOR MERCURY (FEDERAL REGULATIONS) APPENDIX K PART 212: GENERAL PROCESS EMISSION SOURCES (NYS REGULATIONS) APPENDIX L PART 219: INCINERATORS (NYS REGULATIONS) APPENDIX M PART 222: INCINERATORS--NEW YORK CITY, NASSAU AND WESTCHESTER COUNTIES (NYS REGULATIONS) APPENDIX N MUNICIPAL SOLID WASTE INCINERATION, REVISED DRAFT OPERATING REQUIREMENTS (NYS REGULATIONS) APPENDIX 0 SUMMARY OF PROCEDURE FOR CONDEMNATION OF PRIVATE PROPERTY Page Financing,.Sludge Management Projects 221 Public Mechanisms Private Mechanisms Public/Private Mechanisms Revenue Sources and,Grants Introduction Revenue Sources Grants SECTION 7. RECOMMENDATIONS 239 Long Term@Recommendations foraegionwide Sludge 239 Septage-Management -General-Recommendations by Alternative 241 Recommendations,for.Each County 245 SECTION 8. PUBLIC COMMENTS 256 APPENDICES VOLUME I Appendices A through 0 VOLUME II 'Computer-Reports,for.Sludge.Management Inventory, -Septage-Hauler:Invedtory, and-Disposal Site 'Inventory LIST OF TABLES Page TABLE 1 VERIFICATION OF SLUDGE QUANTITIES 9 TABLE 2 MUNICIPAL SLUDGE SOLIDS CONCENTRATION 11 TABLE 3 METHODS OF SLUDGE DEWATERING 12 TABLE 4 METHODS OF SLUDGE STABILIZATION 13 TABLE 5 METHODS OF DISPOSING OF SLUDGE 14 TABLE 6 SLUDGE QUALITY 15 TABLE 7 SIZE OF TREATMENT PLANTS IN THE REGION 17 TABLE 8 TREATMENT PROCESSES USED BY STPS 18 TABLE 9 INDUSTRIAL FLOW TO TREATMENT PLANTS 19 TABLE 10 SEPTAGE GENERATION 20 TABLE 11 METHODS OF SEPTAGE DISPOSAL 21 TABLE 12 SLUDGE AND SEPTAGE DISPOSAL SITES INVENTORY 22 TABLE 13 METHODS OF SLUDGE AND SEPTAGE DISPOSAL (TOTAL 22 FOR ALL COUNTIES) METHODS OF SLUDGE AND SEPTAGE DISPOSAL BY COUNTY: TABLE 14 DUTCHESS COUNTY 23 TABLE 15 ORANGE COUNTY 24 TABLE@16 PUTNAM COUNTY 25 TABLE 17 ROCKLAND COUNTY 26 TABLE 18' SULLIVAN COUNTY 27 TABLE 19 ULSTER COUNTY 28 TABLE 20 WESTCHESTER COUNTY 29 TABLE 21 POPULATION DATA: 1985 32 POPULATION PROJECTIONS: 2000 Page TABLE 22 EXAMPLES OF PATHOGENS FOUND IN OR GENERATED DURING 46 COMPOSTING TOGETHER WITH HUMAN DISEASES ASSOCIATED WITH THESE PATHOGENS TABLE 23 COST ANALYSIS OF COMPOSTING AT VARIOUS FACILITIES 59 TABLE 24 SLUDGE AVAILABLE FOR LAND APPLICATION 67 TABLE 25 HEAVY METAL CONCENTRATIONS IN SEPTAGE COMPARED TO 69 TECHNICAL DOMESTIC WASTEWATER SLUDGES TABLE 26 ACREAGE REQUIREMENTS FOR LAND APPLICATION 70 TABLE-27 COMPARISON OF COSTS TO USE OCEAN DUMPING AT THE 106 74 MILE SITE FOR BOSTON, NEW YORK CITY AND WESTCHESTER TABLE 28 CO-INCINERATION FACILITIES IN THE UNITED STATES 90-93 TABLE-29 TYPICAL CHEMICAL ANALYSIS OF CARBON AND MOISTURE-FREE 97 INCINERATOR RESIDUE TABLE 30 EP TOXICITY TEST RESULTS: OBSERVED CONCENTRATIONS 98 TABLE 31 PROXIMATE ANALYSIS OF PYROLYSIS CHAR 102 TABLE 32 HEATING VALUE OF TYPICAL RESIDUALS COLLECTED DURING 103 SEWAGE TREATMENT TABLE 33 COMPARATIVE HEATING VALUES OF PERTINENT FUELS 104 TABLE 34 REPRESENTATIVE CHEMICAL ANALYSES AND HEAT CONTENTS 105 OF DRY REFUSE AND SEWAGE SLUDGE SAMPLES TABLE 35 HEAT RELEASED ON COMBUSTION OF REFUSE AND SEWAGE ill SLUDGE TABLE 36 CARVER-GREENFIELD DEHYDRATION WITH ENERGY RECOVERY 127 TABLE 37 SLUDGE CONCENTRATION PRODUCED BY CENTRIFUGAL 136 DEWATERING TABLE 38 TYPICAL DEWATERING PERFORMANCE OF BELT FILTER PRESSES 140 TABLE 39 TYPICAL DEVATERING PERFORMANCE OF A VARIABLE VOLUME 145 RECESSED PLATE PRESSURE FILTER TABLE 40 EXPECTED DEWATERING PERFORMANCE FOR A TYPICAL FIXED 146 VOLUME RECESSED PLATE PRESSURE FILTER TABLE 41 COMPARISON OF DEWATERING-PROCESSES 30 Page TABLE 42 COSTS TO IMPLEMENT SLUDGE MANAGEMENT OPTIONS 158 TABLE 43 COST PER TON FOR SLUDGE MANAGEMENT OPTIONS 158 TABLE 44 PROJECTED QUANTITIES OF OTHER WASTESTREAMS FROM 160 THE SEWAGE TREATMENT PROCESS' TABLE 45 CONTAMINANTS REGULATED BY NYSDEC 174 TABLE 46 SUITABILITY OF SOIL AND SITE CHARACTERISTICS FOR 176 SLUDGE APPLICATION TABLE 47 WASTE FEED RATES AND 14ETROD DURING TESTS ON CONTRA 188 COSTA MULTIPLE HEARTH INCINERATOR TABLE 48 CURRENT BASIS FOR DETERMINING THE APPLICABILITY OF 192 THE NSPS TO INCINERATORS TABLE 49 SLUDGE MANAGEMENT FACILITY SITING CONSTRAINTS 195 TABLE 50 SUMMARY OF PROCUREMENT PROCEDURES 215 TABLE 51 INSTITUTIONAL MECHANISMS FOR'SLUDGE MANAGEMENT 218-220 PROJECTS TABLE 52 FINANCING MECHANISMS FOR SLUDGE MANAGEMENT PROJECTS 224-233 TABLE 53 REVENUE SOURCES 236 TABLE 54 SOURCES OF GRANTS 237-238 LIST OF FIGURES Page FIGURE 1 EFC SLUDGE QUALTITY EVALUATION CRITERIA 16 FIGURE 2 INDIVIDUAL AERATED PILE 41 FIGURE 3 EXTENDED AERATED PILE 42 FIGURE 4 TYPICAL PROCESS FLOW: SCH M TIC OF A CONFINED 44 C014POSTING SYSTEM FIGURE 5 TYPICAL SECTION: MULTIPLE-HEARTH DRYER 81 FIGURE 6 FLOWSHEET FOR SLUDGE INCINERATION IN A MULTIPLE 83 HEARTH FURNACE FIGURE 7 TYPICAL SECTION OF A FLUID BED REACTOR 84 FIGURE 8 FLOWSHEET FOR SLUDGE INCINERATION IN A FLUID BED 85 FURNACE FIGURE 9 CODISPOSAL SYSTEM--PROCESS SCHEMATIC AND 88 MATERIALS BALANCE FIGURE 10 CARBORUNDUM'S TORRAX R PYROLYSIS FACILITY 100 FIGURE 11 EFFECTS OF SLUDGE MOISTURE AND VOLATILE SOLIDS 107 CONTENT ON GAS CONSUMPTION FIGURE 12 RECOVERABLE HEAT FROM COMBUSTION OF SEWAGE 108 SLUDGE FIGURE-13 SLUDGE/REFUSE RATIO REQUIRED FOR SELF-SUSTAINING 109 COMBUSTION FIGURE 14 THERMODYNAMIC SYSTEM BOUNDARY ABOUT A TYPICAL 110 THERMAL PROCESSING SYSTEM FIGURE 15 POUNDS OF WATER TO BE EVAPORATED FOR EACH FOUND OF 113 DRY SOLIDS AS A FUNCTION OF THE PERCENT SOLIDS IN 0 THE SLUDGE FIGURE 16 FLASH DRYER SYSTEM 114 FIGURE 17 SCHEMATIC OF ROTARY DRYER 116 0 FIGURE,18 JACKETED HOLLOW--FLIGHT INDIRECT DRYER 117 FIGURE-19 ALTERNATIVES AVAILABLE FOR EXHAUST GAS DEODORIZATION 118 AND PARTICULATE REMOVAL 0 Page FIGURE 20 SLUDGE DRYING SYSTEM USING THE JET MILL PRINCIPLE--- 119 TOROIDAL DRYER FIGURE 21 CARVER-GREENFIELD MULTI-EFFECT EVAPORATION PROCESS 121 FIGURE-22 FALLING FILM EVAPORATOR DETAILS 122 FIGURE 23 B.E.S.T. PROCESS FLOW SCHEMATIC 124 FIGURE 24 BASKET CENTRIFUGE SCHEMATIC DIAGRAM 132 FIGURE 25 SCHEMATIC OF TYPICAL SOLID BOWL DECANTER CENTRIFUGE 134 FIGURE 26 DISC TYPE CENTRIFUGE 135 FIGURE 27 THREE BASIC STAGES OF A BELT PRESS 138 FIGURE 28 BELT PRESS DEWATERING PROCESS 139 FIGURE 29 SCHEMATIC SIDE VIEW OF A RECESSED PLATE PRESSURE 141 FILTER FIGURE 30 PLATE-FRAME FILTER PRESS 142 FIGURE 31 CONVENTIONAL LOW PRESSURE FILTER PRESS SYSTEM 144 FIGURE 32 TYPICAL SLUDGE DRYING BED CONSTRUCTION 147 FIGURE 33 ROTARY DRUM VACUUM FILTER. 149 FIGURE 34 SUMMARY OF EMISSIONS TESTS ON THE CONTRA COSTA 190 MULTIPLE-HEARTH INCINERATOR FIGURE 35 SUMMARY OF PAR TICULATE EMISSIONS FROM TWO MUNICIPAL 191 REFUSE INCINERATORS FIGURE 36 SLUDGE MANAGEMENT FACILITY SITE EVALUATION MATRIX 197-201 SUMMARY The Hudson Valley has seen substantial growth in the last 10 years. Accompanying residential, commercial and industrial development is resulting in increasing quantities of solid waste, sludge and septage needing treatment and disposal. Sludge and septage have not been considered a serious management problem in most of the United States. Even today, many communities provide no or marginal treatment, and disposal is into convenient bodies of water or in landf ills. Stricter regulations, particularly in New York State, are forcing municipalities to plan for proper waste management. Previously, sludge went to landfills for disposal along with garbage. The New York State Department of Environmental Conservation's 1986 policy of forbidding new or expanded landfills over principal aquifers will severely limit the number of landfills available for both solid waste and sludge. Likewise, as more emphasis is placed by New York State on cleaning up contaminated waterways and waste dumps, both sludge and septage need to be properly treated and disposed. The Hudson Valley was particulary affected both by the more stringent state regulations and by the closing of two sludge disposal facilities: one at Stewart Airport operated by Monteco, and the Merion Blue Grass Sod Farm in Orange County. These closings created a crisis for municipalities which now have to send their sludge and septage longer distances to disposal sites. It was this situation which caused seven counties in the region to ask the New York State Environmental Facilities Corporation to investigate alternatives for managing their sludge and septage. These counties are: Dutchess, Orange, Putnam, Rockland, Sullivan, Ulster and Westchester. They provided partial funding for this study through the Hudson Valley Regional Council and by offering in-kind services. The New York State Department of State provided the balance of funds. This study looks at five management alternatives and recommends the applicability of each to the seven counties. In addition, it presents in-depth analyses of data provided by the counties for sludge quantity and quality, septage generation and disposal and disposal sites and practices for both types of waste. The report describes the current regulations applicable to the five alternatives and projects trends for regulatory policy based on conversations with state and federal officials. Finally, it presents information on developing and financing sludge management projects, and makes three types of recommendations: general to all counties, specific to each county, and by management alternative. The following is a summary of the management and alternatives recommendations. A complete discussion of recommendations may be found in Section 7. Management,Recommendations 1. The seven counties should take immediate action to develop a regional sludge and septage management system. 2. The counties, by formal action of the county legislatures, should establish a permanent regional sludge management task force. Membership should include representatives of the counties and, where appropriate, local governments. Membership should also include individuals with technical competence and experience in sludge management. 3. The counties should consider retaining the Environmental Facilities Corporation to provide technical management services to the task force. 4. The counties should engage the Hudson Valley Regional Council to coordinate the activities of the task force. Technical Recommendations 1. The seven counties should consider developing a regional integrated management plan for sludge encompassing three alternative technologies: inc ineration, land application, and landfill. One site could serve several purposes. A minimum of 200 acres would incorporate an incineration facility and a landfill. Land application, while a component of a management plan, could take place away from the integrated site by using active agricultural land. County studies have already identified a number of potential sites for land application. The next step would be to proceed with a detailed site selection process. 2. The amount of useful data presently available on the quality of sludge in the region is limited. As quality and, more particularly, the presence or absence of toxic materials is the major consideration for selecting alternative methods of disposal, this data must be obtained without delay. A regionally coordinated program should be instituted to provide necessary sampling and laboratory analysis. A minimum of six months of data must be included with an application to NYSDEC for a permit. 3. Land application of sludge is the preferred and least costly alternative. However, its use is limited to sludge co 'ntaining no toxic materials. Land need not be acquired if cooperative agreements can . be.made with farmers. The chief benefit of land application is that it provides beneficial nutrients to the soil for non-food crops at no cost to the growers. 4. Incineration should be used for sludge containing toxic materials. 5. Composting of sludge holds promise for the future. EFC encourages the counties to implement composting on a limited or pilot scale. The composting project could be located at the regional integerated site. 6. Landf illing should be used only as a last resort and as a backup for other options. 7. Ocean disposal of sludge, presently used by one STP in the region, the City of Yonkers, is a low cost option. Ocean disposal could be considered for disposal of additional sludge in the region, but the availability of this option after 1991 cannot be predicted. USEPA policy is to grant a permit only if no other viable alternative exists. 8. Septage should be managed regionally through a system of designating specific STPs, on the basis of cost effectiveness and capacity to receive sep tage. These plants should be modified to provide necessary additions to treatment processes so that septage is not simply mixdd with incoming sewage. M SECTION 1. INTRODUCTION Background In the spring of 1985, the Merion Blue Grass Sod Farm (Sod Farm), located near Middletown, and Monteco located at Stewart Airport, discontinued ope ration as sludge management facilities. The closure of these facilities left many municipalities in the Hudson Valley region without a disposal alternative for the increasing quantities of sludge generated by sewage treatment plants. The Sod-Farm and Monteco operations developed against a background of limited available options for environmentally safe sludge d i s p o s a I .New solid waste regulatory criteria promulgated in 1981 led to virtually all landfills in the region becoming ineligible for (New York State Department of Environmental Conservation (NYSDEC) approval. In addition, many smaller plants using septage disposal sites were prohibited from thi s practice by the new solid waste regulations coupled with more active enforcement. The Monteco and Sod Farm operations sought to land apply sludge in compliance with NYSDEC regulations, and these alternatives initially gained wide acceptance in the region. As these facilities began to receive more and more sludge and septage, their ability to handle these residuals in an environmentally acceptable manner became severely taxed. The Stewart Airport Commission forced Monteco to close for lease violations, and the Sod Farm was shut down by NYSDEC for contravention of groundwater standards. The near simultaneous closure of these facilities created a crisis situation in the region: sludge could not be removed from sewage treatment plants and homeowners could not get their septage tanks pumped. Both of these solid waste situations can have long range and serious ramifications to the quality of ground and surface waters if not promptly resolved. In 1985, seven counties in the Hudson Valley--Dutchess, Orange, Putnam, Rockland, Sullivan, Ulster and Westchester--realized the severity of the sl udge and septage disposal problem in their reg ion and asked the New York State Environmental Facilities Corporation (EFC) to do a study of regional sludge management alternatives. The counties, through the Hudson Valley Regional Council (HVRC), their off icial intergovernmental agency, contributed $35,000 in funds and $30,000 of in-kind services to the study. The New York State Department of State provided an additional $35,000 of coastal management monies. The New York State Environmental Facilities Corporation which carried out thi s study, is a state public benefit corporation with extensive experience in planning, designing, financing, constructing, maintaining, operating, and providing advisory services to municipalities for pollution control projects. EFC's projects include wastewater treatment works and collection systems, air pollution control facilities, water management facilities, storm wat 'er c ollection systems, and solid waste management facilities for resource recovery and industrial hazardous waste treatment, storage and disposal. EFC also provides loans, through the sale of its tax-exempt, special revenue bonds, to private industry to finance pollution control and solid waste management projects. Under another program, EFC assists industry in the reduction, reuse and recycling of industrial and hazardous wastes. The Hudson Valley Regional Council formed in 1978, is the official intergovernmental agency serving the counties of the Hudson Valley. Its representation includes the county executives and county legislative chairmen plus at least one other publicly elected official from the seven counties. Sludge Management in the-,Last Decade An unprecendented level of sewage treatment plant (STP) construction occurred over the last decade, initiated by the federal Water Pollution Control Act of 1972 and aided by a federal construction grants program which provided funding up to a maximum of 75 percent of eligible project c o s t s .New York State funded an additional 12 1/2 percent, bringing the maximum funding level to 87 1/2 percent of eligible project costs. In a d d i t i o nIstate and federal laws mandated secondary and, in some cases, tertiary treatment levels to achieve water quality goals. This construction activity has redirected a continually increasing wastestream from the natural environment into the controlled environment of the sewage treatment plant. Essentially, a sewage treatment plant separates wastewater into waste sol ids ( sludge) and water, its basic components. Its ultimate function is to prevent the contamination of surface and groundwaters and avoid public health, environmental and aesthetic consequences of water pollution. A properly operating STP removes approximately 85 percent of pollutants and discharges a relatively clean effluent. The residual material, sludge, must then be managed in a manner that does not permit its uncontrolled reentry into the environment. While increased awareness of surface water contamination stimulated STP construction, adequate approaches to proper disposal of increasing amounts of sludge have lagged . Currently, firm plans for sludge disposal are required by regulatory agencies during the facility development stage of STP projects. In the past, however, disposal of sludge, a solid waste, was not recognized as a significant problem, and co-disposal with other solid waste streams, generally at local landfills, was taken for granted. As sludge quantities increased, ultimate disposal of this material presented problems that stimulated research to develop acceptable disposal strategies and techniques. The disposal problems, also, prompted an increasing number of laws and regulations. Now, the implementation of solid waste disposal options has significantly lagged behind the generation of sludge because: 2 � appropriate regulations have only recently been developed 0 the extensive level of environmental safeguards dictated by New York State and federal regulations contribute to the high cost of sludge disposal projects � funding programs have not been available to stimulate project construction. Description of this Study This study presents the following information: An inventory of municipal sludge and septage in the seven county region 0 A projection of additional sludge generation in the region based on present and projected population An overview of current and planned sludge management activities in the region � Specific recommendations for alternative management technologies � Recommendations for funding mechanisms available to construct and operate future facilities a Recommendations for potential regional locations for sludge management facilities � Evaluation of the cost and benefits associated with each recommendati6n. Scope of Work The contract with HVRC and the Department of State (DOS) requires that EFC perform specific tasks: A. Prepare a written report containing: � Existing data on the quantity and quality of sludges and domestic septage � A description of existing reports and studies prepared for the counties o Population and transportation data � Information about present and planned sludge disposal methods in the seven counties 3 � Information on major sludge treatment and disposal technology alternatives: land based (composting, land application, landfill) thermal reduction and ocean disposal � Information about existing and former sludge and septage management sites � A discussion of existing and potential grants and other prospective sources of funding, and financial and technical assistance � Legal, financial and institutional mechanisms for alternative management approaches � A description of current federal and state regulations and potential trends for the future � Criteria for siting specific types of management facilities. B. Provide technical assistance by: e Meeting with county, HVRC and Department of State representatives each month * Assisting with press releases and public participation, including public information meetings on the contents of the report * Coordinating with USEPA, Department of State, New York State Department of Environmental Conservation, county and other state agencies to obtain their input * M4eting with the New York State executive department and members of the legislature. The complete Scope of Work is described in Appendix A. EFC and NYSDEC Project Staff @Terence P. Curran, P.E., Executive Director had overall project management res ponsibility for EFC. Administration was provided by Pickett T. Simpson, P.E. , Manager of Hazardous Waste Programs and Diana M. Hinchcliff, Executive Assistant to Mr. Curran. Ms. Hinchcliff edited this report. Kenneth F. Malcolm was the project manager with day-to-day responsibility for implementation. Peter A. Marini P.E., Marian J. Mudar and J. Andrea Estus assisted with writing sectio;s of the report. William H. Holmes, President, Holmes Brothers, Inc., William B. Pressman, P.E., and Joseph E. Silber, P.E. provided consultant services. Mary Johnson Blass typed the many drafts and the final report assisted by Donna Melcher. 4 NYSDEC officials participated actively in the task group by attending many of the group meetings as well as by reviewing draft sections of this report for regulatory accuracy. NYSDEC was particularly helpful in providing data in addition to that furnished by the counties, and offering suggestions for project implementation. Thomas Easterly, P.E., Section Chief, Division of Solid and Hazardous Waste, Albany, and Edward Cassidy, P.E., Solid Waste Engineer, Region 3, were especially helpful. Technical Task Group To provide EFC with adequate information about regional and local problems as well as technical experience, one technical represenative from each county plus a project auditor from the Hudson Valley Regional Council were appointed to a task group. County members were: DUTCHESS COUNTY Robert Vrana, Commissioner Solid Waste Management ORANGE COUNTY Matthais Schleifer, Assistant Commissioner Health Department PUTNAM COUNTY Anne Bittner, Assistant Public Health Engineer Division of Environmental Health Services ROCKLAND COUNTY Charles Stewart, Executive Director Rockland County Sewer District No.1 SULLIVAN COUNTY John Fink, Engineering Supervisor Department of Public Works ULSTER COUNTY Dean Palen, Director of Environmental Sanitation Health Department WESTCHESTER COUNTY Peter Eschweiler, Commissioner Department of Planning HUDSON VALLEY Hildegard Frey REGIONAL COUNCIL Economic Development Coordinator Additional representation was provided by the counties where it was appropriate for a specific purpose. Task Group-Activities The task group initially focused on providing basic data on sludge and septage generation and disposal practices for EFC staff to use in developing computer programs to characterize the present situation. This information was used by EFC to forecast the future and develop disposal options possible under assumed conditions. 5 Monthly meetings were held at various locations in the study region. These meetings provided an opportunity for discussion of the data submitted by the county representatives as well as a forum for discussion of EFC's use of this data, and .,the conclusions, in terms of available options, that the data yielded. Midway through the study period, the meetings focused on specific disposal alt ernatives. Generally, these meetings were highlighted by EFC's informal presentation of a disposal option, composting, for example, followed by a discussion among all present. Draft sections of the report were distributed and copies mailed to those not in attendance, with the request that the material be reviewed and comments returned within a prescribed time. The comments were then incorporated into the evolving report. To aid in its deliberations, the task group visited the Glen Cove, Long Island, resource recovery project where sludge is co-incinerated with mun icipal solid waste for heat recovery and electricity generation, and the Hoboken, New Jersey plant, where an oxyozosynthesis* process is used to stabilize sludge. Oxyozosynthesis is a stabilization process using oxygen and ozone whicil results in a highly dewaterable sludge. 6 SECTION 2. DATA COLLECTION AND ANALYSIS Introduction Three computer programs were developed during this study to collect and evaluate data provided by the counties. This data yielded three inventories: sludge inventory, septage hauler inventory and disposal site inventory. The Sludge Management Inventory contains information about the sludge generated by sewage treatment plants in the region including quantity, quantity flows and processes. The Septage Hauler Inventory presents names of haulers, disposal site locations and quantities hauled. The Disposal Site Inventory provides names of disposal sites, quantities of refuse, sludge and septage disposed of annually at the sites, methods of disposal and sizes of the sites. Difficulties With-Collecting-Data Sufficient data to adequately characterize the quantity and quality of sludge and septage is not presently available from the generators in the area addressed by this study. EFC believes this is consistent with the situation throughout New York State as well as the United States as a whole. This absence of critical data results from: a) the lack of regulatory req uirements, and b) little or no awareness at the municipal planning level of the importance to proper sludge management of accurate data. Effluent at sewage treatment plants is monitored closely because of regulatory emphasis on water quality, but attention to solid waste generated by wastewater treatment is a lower priority. Without a regulatory mandate or a change in perception on the part of municipalities, this situation is likely to continue. The inconsistency of the data does not allow EFC to estimate sludge quality for this report with any degree of confidence. Neither is it possible to be specific about the size of sludge management facilities nor to determine appropriate equipment needs. EFC encountered some common problems while attempting to obtain data: 1. Most STPs do not maintain a proper accounting of sludge quantities removed from municipal sewage treatment plants. Quantities removed for disposal should be characterized in terms of dry tons. While a plant does not dispose of dry tons of sludge, per se, this is a common denominator when considering management options and may be readily calculated if accurate records are kept in terms of gallons or cubic yards and percent solids or total solids. This is especially a problem with the smaller facilities (less than one million gallons per day). 7 2. With a few exceptions, analyses for sludge quality (heavy metals, toxics, potential plant nutrients, and heating values) are not done with a frequency that would adequately characterize these parameters for a given residual. When EFC reviewed the data supplied by the counties (Table 1), many plants kept no information and others had conflicting data. Periodic analyses conducted over a period of time (at least six months) would be necessary to accurately determine sludge quality. Because of the high level of concern for environmental quality reflected by tight regulatory controls, specific sludge management planning efforts cannot go beyond the theoretical stage without adequate quality data. 3. A substantial percentage of the sludge generated in the region contains high levels of copper. In some cases the sources of copper have been investigated but have not been found. Industrial discharges do not seem to be the source of this contaminent. Suggested 'sources are high background levels of copper in water supplies or extraction of copper from plumbing systems by corrosive action. As sludge contaminated by copper or other restricted substances severely limits disposal options, EFC recommends that the source of this problem be determined and an approach developed that will either eliminate or provide proper disposal of the contaminent from the waste stream. 4. The spectrum of sludge disposal alternatives includes land application, landfilling, composting, incineration, and ocean disposal. Contaminated sludge, i.e. exceeding New York State Department of Environmental Conservation guidelines, cannot be applied to land or composted. As long as the sludge cannot be classified as a hazardous waste, it may be landfilled, although landfill space is limited and new regulations make landfills a costly option. While ocean disposal is not restricted to sludge of a certain quality, the fate of this option after the current five year interim review period is uncertain. Ocean disposal may be discontinued altogether or new criteria may be developed for sludge quality. At this point, the best alternative for disposal of a contaminated sludge appears to be incineration. However, air quality standards for incinerating sludge are in a state of flux and a concentration of contaminents in incinerator ash can create additional disposal considerations. Sludges containing contaminents will face more and more restrictions and have fewer and fewer disposal options. Presently, the most prudent course of action appears to be removal of the contaminents from the waste stream by,means of pretreatment programs or other methods. 8 Verification,of Sludge Quantities While reviewing data submitted by the counties, EFC noticed apparent inaccuracies in sludge quantities reported. A method was needed by which to determine what actual quantities ought to be. The current literature was reviewed in an effort to find a factor, or multiplier, by which actual quantities could be estimated (see Ap'pendix B). Based on available information, a factor of 0.692 dry tons/million gallons (dt/mg) was used. Thi s fctor was multiplied by the daily dry flow of a sewage treatment plant (STP) times 365 days/year as in this example: 0.692 dt/mg X 9 mg (dry flow) X 365 days = 2,273.22 Dry Tons yr yr Thi s ver ification calculation was made for the data submitted for each STP as well as for each countyts total and the grand total for all counties. The difference between reported and calculated values was computed, as well as a "reliability factor" (F) of reported vs. calculated. A reliability fac tor of I would indicate agreement in reported and calculated values; 0.5 would indicate one-half the quantity calculated was reported; 2.00 would indicate twice the quantity calculated was reported, and so on. A summary of these calculations is shown in Table 1. TABLE I 'Verification of Sludge Quantities (all quantities are in dry tons/year) Calculated Reported Difference F DUTCHESS 3,620 3,289.4 + 330.6 .91 ORANGE 5,670 4,844.9 + 825.1 .85 PUTNAM 402 294.5 + 107.5 .73 ROCKLAND 7,800 5,464.7 + 2,335.3 .70 SULLIVAN 1,803 1,726.6 + 76.4 .96 ULSTER 2,284 1,360.3 + 923.7 .60 WESTCHESTER 31,540 18,727.0 +12,813.0 .59 GRAND TOTAL 53,119 35,707.4 +17,411.6 .67 9 Although Dutchess and Sullivan counties show close agreement between reported and calculated values, individual differences within those counties are sometimes substantial. This indicates some STPs overestimated while others underestimated quantities generated. EFC realized early that this situation was occurring and held lengthy discussions with county techical representatives at monthly meetings. In an effort to get data with a higher reliability factor, copies of each county's data were distributed to each representative for verification. The figures above reflect that effort. This situation creates a data reliability problem which is especially critical when sludge quality is considered. Incorrect quantities or proportions of clean to contaminated sludges may lead to unjustifiably favoring one management alternative over another. The reader should consider all data presented in this section and throughout this study as approximate. As the seven-county region encompasses 154 treatment plants, 76 disposal sites and 86 septage haulers, a case-by-case analysis to verify data was obviously not practical considering the constraints of time and available funding. EFC recommends that the counties develop -programs-to monitor sludge quantity -produced at each -ST?i quantities- of, septage- generated- in each @-county, quant.it.ies of -sludge -an& septage deposited at-all disposal sites with-in the -region, and sludge quality at all STPs (heavy metal concentrations - and EP, toxicity). An.appropriate. routine- testing schedule should .@ be developed. based- on -the- findings, of, the- initial analysis and the .size of the, facility. Such analyses@should-be-conducted-at least once per ,year. 10 SLUDGE MANAGEIMENT INVENTORY Municipal-@Sludge,.Solids...Concentration Sewage treatment separates the components of sludge: solids and liquid wat er. The water is used merely as a means to transport the waste from the point of-origin to the sewage treatment plant. The normal solids concentration in wastewater is on the order of 200 parts per million (ppm) or 0.02 percent. Effective wastewater treatment will increase this concentration to approximately 20 percent. The 20 percent solids concentration is a minimum for sludge to be accepted at a landfill, for cost-effective composting, and for cost-effective incineration. As shown in Table 2, approximately two-thirds of the sludge presently generated does not meet the minimum of 20 percent solids. Seventy-five percent of the STPs in the region cannot dewater sludge to this minimum level. TABLE 2 Number of Percent of Number of Percent of STPs Total STPs Tons* Total Tons > 20% Solids 40 26 13,113 37 < 20% Solids 114 74 22,594 63 TOTALS 154 100% 35,707 100% Tons are in dry tons > greater than or equal to < less than Methods of Sludge,Devatering @Sludge is dewatered to reduce transportation costs from the STP to the ultimate disposal site as well as to provide enhanced opportunities for dis posal . Presently, the only disposal options for liquid sludge are land application or ocean disposal. All other major disposal alternatives -- landfill, composting, incineration--require some dewatering. Table 3 enumerates the types of dewatering equipment used in the region, their frequency of usage, and the amount of sludge they dewater. The information in this table may be considered an inventory of dewatering equipment in the region. The type of dewatering equipment is generally a major determining factor in solids concentration or sludge drying capability. For example, if an incineration alternative is considered and the process selected requires a 25 percent solids concentration (75 percent moisture), some idea of the capability of meeting this requirement can be obtained by consulting this inventory. The most significant factor revealed by the sludge dewatering inventory is that 43 percent of the sludge generated in the region is not dewatered. SI udge which is not dewatered has limited disposal potential as well as the potential for creating an extra cost burden if significant transportation is necessary. TABLE 3 Number of Percent of Number of Percent of Method STPs Total STPs -Tons* Total Tons Vacuum Filter 9 6 10,472 29 Centrifuge 8 5 3,828 11 Air Drying 41 27 2,443 1 Belt Press 6 4 1,810 5 41 Filter Press 3 2 1,557 4 Sludge Lagoon 1 1 220 1 Vacuum Drying Beds 1 1 67 1 Total Devatered 69 46% 20,397 58% Not Dewatered 85 54% 15,310 42% TOTALS 154 100% 35,707 100% Tons are in dry tons 12 Methods of Sludge-Stabilization Sludge stabilization reduces the organic material present in sludge which in turn reduces the potential for odors. Stabilization, in addition, significantly reduces the number of possible disease-causing agents (pathogens) to acceptable levels. Depending on the ultimate use or disposal method of the sludge, a process to further reduce pathogens may be required (see Section 3 for more information). An inventory of the sludge generated in the region based on the stabilization methods employed is provided in Table 4. This will help det ermine the suitability of a sludge for a particular disposal method. Of particular interest here is that 30 percent of the sludge generation sites (STPs) which account for 18 percent of the sludge gener9ted have no stabilization process. Unstabilized sludge may not be landfilled or land applied, but may be composted, ocean disposed, or incinerated. TABLE 4 Number of Percent of Number of Percent of Method STPs Total STPs Tons* Total Tons Stabilized Anaerobic Digestion 51 33 18,326 51 Lime Addition 6 4 5,051 14 Aerobic Digestion 46 30 2,929 8 Zimpro+ 1 1 3,080, 9 Air Drying 4 3 209 1 Total Stabilized 108 71% 29,595 83% Not Stabilized 46 29% 6,112 17% TOTALS 154 100% 35,707 100% + Zimpro is a wet air oxydation system used only at one site in New Rochelle, Westchester County. Tons are in dry tons 13 Methods of-Disposing of-Sludge Table 5 characterizes present methods employed by STPs in the region to dispose of sludge. Ocean disposal accounts for the majority of sludge disposed in the region. The Yonkers plant, producing about one-third of all sludge in the region, use's this method. Composting, land application and other methods account for a very small proportion of sludge disposal. TABLE 5 Number of Percent of Number of Percent of Method STPs Total STPs Tons* Total Tons Ocean Disposal 3-- 2 12,615 35 Incineration 8 @5 9,852 28 Landfill 45 29 10,688 29 Land Application 11 7 412 1 Scavenger Hauling+ 62 40 649 2 Composting 10 7 947 3 Stockpiled on Site+ 7 5 349 1 Treatment Lagoon 6 4 195 1 Other 2 1 0 0 TOTALS- 154 100% 35,707 100% + Although stockpiling and scavenger hauling are not disposal methods, per se, these quantities are included for accounting purposes. Tons are in dry tons 14 Sludge Quality For purposes of this study, EFC has assigned letters designating certain levels of sludge quality based on the level of contamination present. Basically, "A"-rated sludge may be considered clean, "C"-rated sludge is contaminated (land application or composting options are prohibited), and "D"-rated sludge is somewhat contaminated and.may be used with certain restrictions. See Figure I (page 16) for specific quality guidelines. Quality limits occur in NYSDEC regulations for land application and composting. These quality limits are used to provide some relative criteria for evaluating disposal alternatives. Currently, no contaminent limits exist for incineration or ocean disposal. Landfill limits for sludge disposal are based on hazardous waste regulations, i.e. sludge that does not -exceed hazardous waste limits may be landfilled. No sludge analysis reviewed during the course of the study exceeded hazardous waste limits. Approximately 70 percent of the sludge generated in the region is analyzed to some degree for quality. However, as previously mentioned, consistent schedules of analysis are not maintained by the STPs, making accurate data evaluation impossible. Nineteen percent was rated "A", 8 percent of the sludge was rated "C", 42 percent was rated "W'. TABLE 6 Number of Percent of Number of Percent of Rating STPs Total STPs Tons* Total Tons Rated A 22 14 6,596 19 C 11 7 2,873 8 D 18 12 15,026 42 Total Rated 51 33% 24,495 69% No Rating 103 67% 11,212 31% TOTALS 154 100% 35,707 100% Tons are in dry tons 15 Figure I EFC SLUDGE QUALITY EVALUATION CRITERIA A-Rated Acceptable Quality for Land Application or Composting of Sludge e Metal content below DEC guidelines as contained in "Solid Waste Management Facility Guidelines" (5/81). e Less than 10 parts per million (ppm) PCB concentration. � Has not been subjected to chlorine oxidation process. � Negative EP Toxicity analysis. � Requires process to significantly reduce pathogens (PSRP). C.-Rated Toxic Prohibition - Not Acceptable for Land Application or Composting * Metal content more than twice NYSDEC guidelines. * Greater than 10 ppm PCB concentration.' * Sludge treatment by chlorine oxidation system. * Positive EP toxicity analysis. D-Rated Acceptable for Use on a Dedicated Site Only � All criteria in "A" are met with exception of metal concentration. � Metal content between I and 2 times NYSDEC guidelines. � NYSDEC variance required. 16 Size of Treatment-Plants-.in-the-Region This inventory was prepared to provide a perspective on the size of treatment plants relative to the relative quantity of sludge generated. The amount of flow for which a sewage treatment plant is designed is generally based on population estimates in the wastewater service area plus the specific amounts of sludge which significant industrial and commercial dischargers will send to the plant. Design flow analyses indicate that although 77 percent of the plants in this region treated less than 1 million gallons/day (mgd) of sludge, they accounted for only six percent of the sludge produced. One plant (Yonkers) accounts for almost one-third of the sludge produced in the region. Plants greater than five mgd (10 percent of the total number) account for 75 percent of the sludge produced. TABLE 7 Number of Percent of Number of Percent of Plant Size STPs Total STPs Tons* Total Tons < 1 mgd 118 76 2,200 6 1-5 mgd 22 14 6,850 19 5-10 mgd 9 6 9,984 28 10-50 mgd 4 3 5,745 16 > 50 mgd .1 1 10,928 31 TOTALS 154 100% 35,707. 100% > greater than < less than Tons are in dry tons 17 Treatment Processes-Used@by STPs The activated sludge process is predominant in this region and is used at plants generating 71 percent of the sludge. Fixed media systems (trickling fil ters and rotating biological contactors) are used for over one-fifth of the sludge generated. All other processes account for only nine percent of the total sludge generated. TABLE 8 Number of Percent of Number of Percent of Process STPs Total STPs -Tons* Total Tons Activated Sludge 65 42 25,807 72 Fixed Media 51 33 7,183 20 Primary Treatment 12 8 2,411 7 Septic Tank 20 13 103 1 Other 6 4 204 1 TOTALS 154 100% 35,707 100% Tons are in dry tons 18 Industrial Flow-to Treatment Plants Industrial flow information provides some indication of present and future potential for an.impact on sludge quality from industrial discharges. The data displayed in Table 9 shows that while only 24 percent of the STPs receive industrial f low,. these facilities account for 86 percent of the sludge generated. Thus, the potential for industrial contamination is high. However, only a small percentage of the STPs' total flow is industrial, making surveillance requirements manageable. TABLE 9 Industrial Flow as a Percent of Number of Percent of Number of Percent of Total Flow STPs Total STPs Tons* Total Tons 1-5% 17 11 21,400 60 5-10% 3 2 984 3 10-20% 7 5 2,062 6 20% + 9 6 6,000 17 Total Industrial Flow 36 24% 30,446 86% 'No Industrial Flow 118 76% 5,261 14% TOTALS 154 100% 35,707 100% Tons are in dry tons 19 SEPTAGE HAULER INVENTORY Septage Generation No analyses of septage solids concentrations could be provided by the counties. USEPA studies indicate that four percent is an appropriate concentration to use when designing facilities. However, EFC's studies showed a high variability, for the four percent parameter when using it to balance reported quantities received and disposed. EFC's investigations led to its conclusion that septage concentrations in the region were apparently about two or two and one-half percent rather than the four percent suggested by USEPA. The dry tons calculated here reflect an average value of 2.4 percent. TABLE 10 Number of Haulers: 86 Total Quantity: 73,000,000 gallons* Total Dry Tons: 10,592+ Solids Concentration: 2.4 percent (average) * Information supplied by septage haulers * Calculated by EFC based on quantity information from haulers 20 Methods-of Septage-Disposal Appraximately one-quarter of the septage generated in the region is hauled to sewage treatment plants for further treatment and disposal. The majority of this material is discharged to the Yonkers plant via the "Hawthorne Manhole". Approximately 28 percent is composted by a single hauler. Land application accounts for 12 percent of septage disposal regionwide. TABLE 11 Number Percent Number of Percent Number Percent of of Tot. Gallons of Tot. of of Total Method Tons* Tons (Million) Gallons Haulers Haulers Land Application 1,220 12 7.315 10 10 12 Composting 3,002 28 18.000 25 1 1 At Treatment 2,506 23 24.510 34 50 58 Plant Lagoon 601 6 3.600 5 10 12 Subtotals: 7 329 69% 53.425 74% 71 83% 'No Method Given 3:263 31% 19.575 26% 15 17% TOTALS 10,592 100% 73.000 100% 86 100% Tons are in dry tons 21 SLUDGE AND SEPTAGE DISPOSAL SITES AND PRACTICES INVENTORY EFC took an inventory of sludge and septage disposal sites and practices to def ine the present situation in the seven county region. Table 12 gives an overview of sludge and septage disposal . Table 13 display sludge and sep tage disposal practices for the region as a whole. Tables 14 through 20 show the same information for each county separately. Information about specific disposal sites has been given to each county by EFC. TABLE 12 SLUDGE AND SEPTAGE DISPOSAL SITES INVENTORY Numer of Sites: 90 Total Septage Disposal: 7,200 dry tons/year Total Sludge Disposed: 34,122 dry tons/year Total Sludge and Septage: 41,322 dry tons/year (This data provided by the counties) TABLE 13 METHODS OF SLUDGE AND SEPTAGE DISPOSAL (Total for All Counties) Number of Percent of Number of Percent of Method Tons Total Tons Sites Total Sites OCEAN DISPOSAL 14,076 34 1 1 LANDFILL 10,684 26 37 42 INCINERATION 10,107 24 5 6 COMPOSTING 2,764 7 4 4 LAGOON 2,141 5 22 24 TREATMENT PLANT 715 2 4 4 LAND APPLICATION 816 2 12 13 TRANSFER STATIONS* 0 0 5 6 TOTALS 41,322 100% 90 100% Transfer stations accept only refuse at this time. If properly equipped, transfer stations could accept sludge and septage. However, these stations are not ultimate disposal sites but only convenient col lection locations to make transportation more economical. Only Dutchess County' supplied information on transfer stations. This information from the other counties is necessary to plan future disposal alternatives. 22 Methods of Sludge,and.Septage Disposal by County DUTCHESS COUNTY All disposal options considered in this study are used by Dutchess with the exception of ocean disposal. This is a somewhat unique situation as most counties use only two or three options. Using several, small-scale options could prove helpful to Dutchess and the other counties in considering future disposal activities because it is easier to expand existing operations than to create new ones. TABLE 14 Number of Percent of Number of Percent of Method Tons* Total Tons Sites Total Sites OCEAN DISPOSAL 0 0 0 0 LANDFILL 1,515 21 13 45 INCINERATION 1,885 25 2 7 COMPOSTING 2,252 31 1 4 LAGOON 851 12 3 11 TREATMENT PLANT 608 8 1 4 LAND APPLICATION 183 3 3 11 TRANSFER STATIONS 0 0 5 18 TOTALS 7,294 100% 28 100% Total Sludge: 3 284 28 sites Total Septage: 4:010 Tons are in dry tons 23 ORANGE COUNTY Most sludge in orange is sent to the Orange County Landfill. A small amount is lagooned with septage at a few sites but this practice does not qualify for a permit under NYSDEC regulations. Land application is practiced at three sites using septage alone. TABLE 15 Number of Percent of Number of Percent of Method Tons* Total Tons Sites Total Sites OCEAN DISPOSAL 0 0 0 0 LANDFILL 3,930 79 5 29 INCINERATION 0 0 0 0 COMPOSTING 0 0 0 0 LAGOON 781 16 9 53 TREATMENT PLANT 0 0 0 0 LAND APPLICATION 225 5 3 18 TOTALS 4,936 100% 17 100% Total Sludge: 4,038 tons I Total Septage: 898 tons 2 Tons are in dry tons In addition to the 4,038 dry tons of sludge shown above, Orange County reports that 415 dry tons are being held or disposed of on-site and 45 dry tons are being transported to New Jersey. 2 As specific disposal site information was not provided f or orange Co unty septage, the following information was provided by the county and is included here at its request: Disposal Site Type Septage Quantity (Dry Tons) STP 392 Lagoons 309 Land Application 651 Composting (Dutchess County) 250 1,602 24 PUTNAM COUNTY As most of the sludge generated in Putnam is sent out of the county for disposal, and most of the septage is transported by out-of-county haulers, it is difficult to match the quantities of septage generated with the sludge disposed in the county. Malcolm Pirnie, in a 1981 report, estimated that about 315.tons of sludge and 666 tons of septage (4.7 million gallons at 3.4 percent solids) are generated within the county. Mos t septage in the county is disposed in the ocean. The Cold Spring plant disposes of air dried sludge at the Phillipstown Landfill. TABLE 16 Number of Percent of Number of Percent of Method Tons* Total Tons Sites Total Sites OCEAN DISPOSAL 0 0 0 0 LANDFILL 26 20 4 44 INCINERATION 0 0 0 0 COMPOSTING 0 0 0 0 LAGOON+ 0 0 2 23 TREATMENT PLANT 107 80 3 33 LAND APPLICATION 0 0 0 0 TOTALS 133 100% 9 100% Total Sludge: 130 tons Total Septage: 3tons * There are two closed lagoon sites in the county. * Tons are in dry tons 25 ROCKLAND COUNTY Rockland uses incineration at the Orangetown STP to dispose of just over half the sludge generated in the county. Forty-three percent goes to the Haverstraw Landfill. A small site located in Ramapo applies to land approximately 200 tons per year of sludge. The majority of septage generated in Rockland is ocean disposed or goes out of state to the Parsippany Landfill in New Jersey. TABLE 17 Number of Percent of Number of Percent of Method Tons* Total Tons Sites Total Sites OCEAN DISPOSAL 0 0 0 0. LANDFILL 2,453 43 1 33.33 INCINERATION 3,021 53 1 33.33 COMPOSTING 0 0 0 0 LAGOON 0 0 0 0 TREATMENT PLANT 0 0 0 0 LAND APPLICATION 200 4 1 33.33 TOTALS 5,674 100% 3 100% Total Sludge: 4,455 tons Total Septage: 219 tons Tons are in dry tons 26 SULLIVAN COUNTY Sullivan County depends primarily on landfi *11 to dispose of sludge. A small amount of sludge and septage is land applied and composted at six sites in the county. One plant (Liberty) is stockpiling sludge due to the lac k of either a dewatering or stabilization process available at the plant sit e. Approximately one-half the septage generated in Sullivan is disposed outside the county. TABLE 18 Number of Percent of Number of Percent of Method Tons* Total Tons Sites Total Sites OCEAN DISPOSAL 0 0 0 0 LANDFILL 1,609 78 4 31 INCINERATION 0 0 0 0 COMPOSTING 30 2 2 15 LAGO014 227 11 2 15 TREATMENT PLANT 0 0 0 0 LAND APPLICATION 169 8 4 31 STOCKPILED 20 1 1 8 TOTALS 2,055 100% 13 100% -Total Sludge: 1,728 tons Total Septage: 327 tons Tons are in dry tons 27 ULSTER COUNTY All sludge in Ulster County is landfilled at various town facilities. All Ulster's septage is lagooned at private sites or hauled to STPs. TABLE 19 Number of Percent of Number of Percent of Method Tons* Total Tons Sites Total Sites OCEANPISPOSAL 0 0 0 0 LANDFILL 1,151 80 9 60 INCINERATION 0 0 0 0 COMPOSTING 0 0 0 0 LAGOON 282 20 6 40 TREATMENT PLANT 0 0 0 0 LAND APPLICATION 0 0 0 0 TOTALS 1,433 100% 15 100% Total Sludge: 1,151 tons Total Septage: 282 tons Tons are in dry tons 28 WESTCHESTER COUNTY Westchester generates and disposes of about 50 percent of the sludge and septage in the region. Approximately 70 percent of this material is sent from the Yonkers STP to be disposed of in the ocean. Incineration is used to dispose of sludge and septage from two plants which represent one-quarter of the region's total. There are land application and composting projects at two other facilities in the county. TABLE 20 Number of Percent of Number of Percent of Method Tons* Total Tons Sites Total Sites OCEAN DISPOSAL 14,076 71 1 20 LANDFILL 0 0 0 0 INCINERATION 5,201 26 2 40 COMPOSTING 482 2 1 20 LAGOON 0 0 0 0 TREATMENT PLANT 0 0 0 0 LAND APPLICATION 38 1 .1 20 TOTALS 19,797 100% 5 100% Total Sludge: 18,336 tons Total Septage: 1,461 tons Tons are in dry tons 29 POPULATION PROJECTIONS AND FUTURE WASTE QUANTITIES Introduction Sludge and septage management facilities planned today must be designed to accommodate wastes generated by a population anticipated in the year 2000. Facilities are commonly designed for a 20 year life. As information on population projections for 2005 was not available, the year 2000 is used in the accompanying table. This section presents 1985 population data and projects population to the year 2000 to forecast future waste quantities and aid in designing management facilities. Explanation of Table Table 21 of this sectidn displays the sewered and unsewered population of each county for the years 1985 and 2000. The percentages in the table were provided by the county technical representatives. From the information in Table 21, EFC estimated that each person in the region generates 117 gallons of septage per year. This figure is somewhat higher than the average per capita septage generat ion rate of 60 gallons recommended by USEPA for planning and design. It should be noted, however, that the regional rate probably includes some commercial and institutional wastes which EPA recommends adding to the average design rate. For the purposes of this report, septage generation rate of 120 gallons per capita per year has been used to project the year 2000 total septage quantity of 71.81 million gallons per year. The table also shows sludge production in 1985 of 35,707 dry tons per year or an average for the region of 0.46 dry tons per million gallons of sewage was te treated. This sludge production rate is dependent on plant processes and will probably increase in the future due to modifications in treatment processes and more efficient operation of STPs. In projecting the sludge quantities, a production rate of 0.692 tons per million gallons of waste flow was used. This is based on the calculations contained in Appendix B. 1 "Handbook: Septage Treatment and Disposal", EPA 1984 41 30 41 The ratio of sewered to unsewe red population is expected to increase from 1985 to the year 2000. This will result in a 10.6 percent increase in sludge production from-35,707 dry tons per year presently to 39,492 dry tons per year in 2000. A corresponding 1.62 percent decrease in septage production from the present 72.99 million gallons per year to 71.81 million gallons per year in 2000 is projected. The impact of the 10.6 percent increase in sludge production must be taken into consideration in implementing a sludge management plan. The slight 1.62 percent decrease in projected septage quantities may be ignored for future planning purposes. 31 TABLE 21 POPULATIOIN DATA 1985 Total % Pop. Un- Pop. Sludge Septage Pop. Sew. Sewered Sew. Unsewered Ton/year Mil. Gal. DUTCHESS 256,563 40 102,625 60 153,938 3,289.4 25.9 ORANGE 275,152 60 165,091 40 110,061 4,844.9 10.6 PUTNAM 80,852 15 12,128 85 68,724 294.5 0.002 ROCKLAND 267,276 93 247)765 7 19,511 5,464.7 11.4 SULLIVAN 67,710 45 30,471 55 37,240 1,726.6 3.48 ULSTER 163,135 37 60,360 63 102,775 1,360.3 2.67 WESTCHESTER 870,723 85 740$115 15 130,608 18,726.7 18.97 TOTAL: 1,981,411 69 1,358,555 31 622,857 35,707.1 73.022 SOURCE: New York State Water Quality Mangement Plan New York State Department of Commerce, September 30, 1985 POPULATION PROJECTIONS 2000 Total % Pop. Un- Pop. Sludge Septage Pop. Sew. Sewered Sew. Unsewered Ton/year Mil. Gal. DUTCHESS 290,541 45 130,744 55 159,797 3,302.3- 19.17 ORANGE 329,109 70 230,376 30 98,733 5,818.8 11.84 PUTNAM 96,695 38 36,744 62 59,951 928.1 7.19 ROCKLAND 315,529 96 302,908 4 12,621 7,650.8 1.51 SULLIVAN 74,159 45 33,372 55 40,787 842.9 5.74 ULSTER 178,283 50 89,142 50 89,141 2,251.5 10.69 WESTCHESTER 870,883 85 740,251 15 130$632 18,697.2 15.67 TOTAL: 2$155,199 73 1,563,537 27 591,662 39,491.6 71.81 .SOURCE: New York State Water Quality Mangement Plan New York State Department of Commerce, September 30, 1985 32 SECTION 3. TECHNICAL ALTERNATIVES FOR SLUDGE MANAGEMENT INTRODUCTION Five technical alternatives for sludge management are presented in this section: sani tary landfill, composting, land application, ocean disposal and thermal reduction. Each technology is described in detail and associated requirements for implementing the technology are discussed. A comparison of the relative cost of each alternative is provided. This section also includes other considerations common to all the alternatives: dewatering and transportation. EFC reviewed available engineering studies prepared for each of the counties to gain a background on past recommendations for sludge and septage management. A summary of these reports is given in this section. SANITARY LANDFILL Requirements-for.Disposing-of Sludge@in a-Landfill Disposal of muaicipal sludge and septage in a sanitary landfill is regulated by the New York State Department of Environmental Conservation (NYSDEC), through Part 360 and NYSDEC's "Solid Waste Management Facility Guidelines". The guidelines define these requirements for a sanitary landfill in New York State to accept sludge: 1. Sewage sludge must be dewatered to a minimum of 20 percent solids by weight and be digested or otherwise stabilized so it is not odorous; 2. The proportion of sludge (wet weight) accepted at a landfill should not exceed 25 percent of the total weight of municipal solid waste with which it is to be mixed unless leachate monitoring treatment and collection is provided; 3. NYSDEC must approve the type, quantity, and general quality of the sludge to be accepted at the site; 4. NYSDEC will approve a "sludge only" landfill under specific conditions set forth in the regulations and guidelines. Where municipal sludge and municipal refuse will be mixed in a landfill, the quantity of sludge which may be received at that landfill depends on the quantities of both sludge and solid waste (MSW) managed at the site. As the amount of sludge that can be accepted into a landfill is limited to 25 percent by wet weight, the contribution of sludge, by volume, is relatively small in relation to the total amount of waste managed. The refore, under this operating condition, construction of new landfills or extensions cannot be based solely on sludge generation, but must take into account MSW generation as the primary consideration. r 33 "Sludge only" landfills require very tight operational controls to prevent both aesthetic and technical problems. The USEPA has published extensive literature on the design and operation of such sites. The parameters that must be met may significantly reduce the viability of this option for the Hudson Valley counties. In addition to the above conditions, several other factors should be considered regarding disposal of sludge and septage at a landfill: � Landfilling sludge and septage does not take advantage of the inherent nutrient and energy value of these materials except when used with cover material where the nutrients can benefit vegetation; � Sludge and septage contain as much as 80 percent moisture. This contributes to the formation of leachate at the site which must be treated and managed so as not to contaminate groundwater; � Landfill capacity should be reserved for wastes for which limited recycling options exist. In the seven county region, rapid growth and lack of available land places landfill capacity at a premium. The NYSDEC Part 360 regulations allow a landfill to accept more than 25 percent sludge by weight provided leachate collection, treatment and mon itoring facilities are incorporated into the facility plan. Discussions with county and NYSDEC representatives indicated that none of ,the landfills meet this requirement. Thirty-seven sewage treatment plants meet the minimum criteria for sludge solids concentration and stabilization. one hundred fourteen plants lack the capability to produce the 20 percent solids cake; 46 plants lack one of the required stabilization processes. Conversely, only 37 plants, accounting for less than one-third of all s ludge produced in the region, meet both dewatering and stabilization criteria. Estimating,the-Cost of a-.Landfill for-Sludge-Disposal .There are a number of factors that can affect the cost of a landfill: 1. Daily, intermediate and final cover requirements could vary the actual cost of operation; 2. Clo sure and post-closure care and monitoring costs should be set aside as the site is. developed; 3. The availability of a municipal sewage collection and treatment system to receive the leachate generated at a site will save the capital cost of a leachate treatment system; 4. The potential for methane gas recovery over the long term could help offset some of the operating costs. 34 Two cost estimates, one for a landfill for all sludge generated in the seven county region and one for a site limited to 100 acres, are presented in Appendix E to illustrate the range of costs and the items which should be included in the facility plan. These estimates demonstrate the higher costs now associated with newer,' more stringent regulatory requirements and, in the case of the smaller site, the limitations inherent in a smaller working area. They are only hypothetical situations and, therefore, serve to display relative cost features of an acceptable facility. It is important to note that a 100 acre landfill will take only about one-fifth of the sludge (in dry tons) generated per day in the region. Five or more sites of this size might be required depending on the depth or height of fill. Estimates of land costs have not been included as they are subject to a very large range in price in the seven county region. They must, however, be included in any specific site estimate and they can be included in the capital cost. 35 COMPOSTING Introduction Sludge composting is the aerobic decomposition of organic materials to a relatively stable, humus-like product. The stabilization process is performed by the activity of microbial organisms (bacteria and fungi) inherent in wastewater sludge. A properly designed composting operation provides the correct environment for this stabilization process to proceed within a reasonable time at an acceptable cost under existing climatic and space I imitations. It must be understood that composting is a stabilization process; it is' not a disposal process. A substantial portion of the sludge component remains, and must be disposed, after the composting process has been completed. The first consider 'ation in implementing any composting system is the availability of a market. The first word of advice from those experienced in composting activities is to conduct a comprehensive market survey for the sale and reuse of compost. The second most important consideration is not to use the market value of compost as an offset against capital or operating costs, as compost value is generally unstable and is generally set by the material it replaces in the marketplace. Compost is considered to be the most stabilized, least offensive, publicly acceptable form of sewage sludge. But while a great deal of time and expense goes into producing compost, its nutrient value, in the form of nitrogen, is reduced by approximately 50 percent. Therefore, the potentially limited market and reduced nutrient value of compost must be compared carefully with the benefits of any composting program. Requirements of-the-,Composting Process Common to all composting processes are the following requirements. Bulking Agents Bulking agents control moisture levels, maintain adequate carbon-nitrogen (C/N) ratios, provide porosity for air circulation, and provide structural stability for compost pile construction. Materials found to be effective bul king agents include wood chips, wood bark, sawdust, rice hulls, shredded tires, and recycled compost. Moisture Control Sewage sludge is usually dewatered to approximately 80 percent moisture content (20 percent solids) prior to use in any composting system. The optimum moisture content for material to be composted is 50 to 60 percent. The structural integrity of piles and air circulation is adversely affected at over 60 percent moisture. A ratio of bulking agent to sludge of approximately 2.5:1 is usual to achieve proper moisture control. 36 Carbon-Nitrogen Ratio (C/N) Microorganisms require 30 parts of carbon for each part of nitrogen used in aerobic respiration. C/ N ratios of 25 to 35:1 are considered ideal for composting. Lower ratios cause nitrogen loss by volatilization and higher values require longer composting retention times. Porosity Bul king agents create voids in the compost mass by addi'ng a random assorted structure (materials of different sizes and shapes to prevent compaction) and by absorbing moisture. These spaces permit the circulation of air required to maintain aerobic conditions. Lack of an aerobic environment will result in offensive odors, require an extended retention period, and result in an inconsistent product. Structural Stability It would not be.possible to achieve the size and relative dimensions of windrows and aerated piles without using bulking agents. The small particle size of unbulked sludge tends to cause it to slide and spread out rather than remain firm. Temperature The optimum temperature for composting is 40 to 55 0C. Lower temperatures decrease the rate of microbial activity and prevent. destruction of pathogenic organisms. Higher temperatures will drive off excessive amounts of moisture, also decreasing microbial activity.. Oxygen The optimum oxygen concentration for composting has been found to be five to 15 percent by volume. Higher levels tend to reduce temperatures. Lower levels can lead to the development of anaerobic conditions. If proper temperatures are maintained, oxygen levels will usually be adequate for composting requirements. Screening Screening the finished compost is necessary to separate and recycle the bulking material and reduce the amount of compost to be managed. The bulking agent is expensive. Effective screening can reduce this cost. Approximately 40 to 70 percent of the bulking agent can be captured and reused depending on the type of equipment used and the moisture content of the finished compost. Moisture levels of 60 percent or more severely hamper effective screening. Leachate Collection and Treatment Condensation of moisture in air handling systems as well as rainfall create leachate with a composition similar to the composted material from which it is derived. Th-is leachate can be treated in a sewage treatment plant. Spray irrigation of the leachate has also been proven effective without causing negative environmental impacts. 37 Mixing The selection of appropriate mixing equipment in relation to the type of bulking agent used and the moisture content of the sludge cake is a significant factor in the success of the composting operation. Inadequate mix ing can lead to a non-homogenous material. This, in turn, will cause an inconsistent final compost in terms of pathogen destruction and moisture content. Odor problems, screen clogging, and excessive drying and curing times can all be related to inadequate mixing of sludge cake and bulking agent. Curing Following the..active composting period (generally 14 to 21 days) a curing period of two to four weeks is usually required to complete the stabilization process and to provide' addit iona 1 drying time. Compost can be screened or unscreened during the curing period. In areas where rainfall interferes with effective drying and curing operations, roofed structures and aeration of the curing piles have been used to great advantage. Volatile Solids (VS) Ratio The VS ratio is a relative measure of the population of microorganisms in sl udge. VS ratios of sludge cake to be composted should be a minimum of 35 percent. Studies show that ratios below this minimum lack sufficient biomass and substrate (food source for microorganisms) for composting. In add ition, inordinate amounts of bulking agent are often needed to supply an adequate carbon source. With normal wastewater sludges the VS should not be a problem. Where a high percentage of inorganic waste, such as an industrial waste, is being treated, or a significant amount of inorganic chemicals, such as ferric chloride or lime, is added during the treatment process VS ratios could become critical. pH The optimum pH for composting is 6 to 8. This range will accommodate the active species of bacteria and fungi involved in the composting process. As it is dif f icult if not impossible to alter the pH of the compost pile, sludge cake to be composted should be within or near this range. Wood products used as a bulking agent provide buffering action and reduce high pH to appropriate levels. Except in extreme cases, pH has been shown to be self-regulating after a few days by virtue of the metabolic processes involved in composting. Composting-Systems Composting systems are divided into two basic types: � Unconfined or open types a. Windrow b. Aerated static pile � Confined or@in-vessel types 38 Windrow System A typical compost windrow is f ive feet high and seven feet wide at the base. Experimentation at a project in Beltsville, Maryland indicates that poured concrete is the ideal base for effective leachate collection and equipment operation. Windrow piles are turned at various frequencies depending on climatic conditions and the age of the pile. Several turnings per day may be necessary for the f irst few days to maintain aerobic conditions, reduce odors, and ensure a homogenous mixture. Thereafter, the compost pile is generally turned on the basis of oxygen availability or temperature within the pile. Oxygen and temperature levels are measured by probes inserted at various points within the pile. As with all systems, temperatures of 40 to 55 0C and an oxygen concentration of five percent by volume are generally considered ideal. After about - five days, the pile is turned once per day for the next 25 to 30 days. The windrow composting process is considered complete when a temperature of 55 0C has been continuously maintained for a period of 15 days. If the material is not to be marketed to the general public, somewhat less stringent regulations apply: the compost temperature may be maintained 0 at 40 0C for five days, and for four hours during the five day period at 55 C. Disadvantages of the Windrow System High potential for and limited control of odors High temperature and moisture variability due to prevailing climatic conditions Larger area required than for other systems More labor- and machine-intensive than aerated pile method due to frequent need to turn pile Final product less homogenous due to varying rates of organic activity within pile Advantages of the Windrow System The only advantages of the windrow may be its simplicity of operation and low capital cost. Although specialized compost turning equipment is preferred, pile turning can be accomplished with conventional front-end loaders if pile construction is consistent with equipment capability. Thus, a basic composting operation can be accomplished on a small scale with little capital investment. Aerated Pile System The aerated pile system was developed to eliminate some of the disadvantages of the windrow system. Using this technique, land requirements are generally reduced by 25 percent, and odors are reduced or eliminated even when composting raw sludge. The addition of forced air ventilation provides the control necessary to achieve a consistent final product and reduce stabilization time. 39 An aerated pile is constructed by placing aeration piping of various configurations, depending on pile dimensions at ground level, over which a six to eight inch layer of bulking agent is placed and extended to the pile edges. The underlayment of bulking agent provides even air distribution, moisture absorption and odor reduction. A sludge to bulking agent mixture of approximately 40 percent solids content (one part sludge at 20 percent solids and two parts bulking agent) is then placed over this underlayment to form a triangular cross section 15 feet at the base by 7.5 feet in hei ght. The entire pile'is covered with a one-foot-thick layer of screened or unscreened cured compost. This covering provides insulation to the pile 49 and reduces odors. The aeration piping header is connected to a blower (generally about 1/3 Hp) which draws air down through the pile on a predetermined time cycle to meet the oxygen and temperature requirements of the pile. (For example, f ive minutes on, 15 minutes off, for a 56 foot long pile containing up to 80 wet tons of sludge.) Aeration times must be monitored fairly closely, as overaeration will cool the pile below effective compost temperatures (550C), and underaeration will cause anaerobic conditions resulting in undesirable odors and a less stabilized product. The use of temperature sensors in a feedback control loop effectively controls aeration. The feedback control loop controls blowers byoC"feeding back" the pile temperature. For example, a temperature of 40 would deactivate blowers .0 while a setting of 55 C would activate blowers. The effluent air may then be piped to a cured compost filter pile or other odor control device for further odor removal. Numerous other pile and aeration configurations are possible depending on site and other limitations. The configuration described above will accommodate approximately three to five dry tons of sludge per acre including space for ru inoff collection, administration, parking, mixing, screening, storage, and other ancillary services. Another type of pile configuration, the extended aerated pile, is designed to reduce the composting site area by approximately 50 percent. This reduction is achieved by more intensive and extensive pile construction. Figures 2 and 3 illustrate extended and individual aerated piles. Pile configurations continue to evolve and are site specific, so it is difficult to determine the exact land area required for a given composting system prior to detailed design. However, for the purpose of preliminary planning, it can be assumed that five dry tons may be composted per acre. Under normal operating conditions, 14 to 21 days of composting time are required to obtain a satisfactory final product. An additional curing period of a few days to one month is necessary to remove excess moisture 4@ and complete the stabilization process. After a stable temperature is achieved within the pile (55 0C), adverse climatic conditions (excessive rainfall or low ambient temperatures) seem to have no effect on the process, assuming proper construction and operation. 40 FIGURE 2 INDIVIDUAL AERATED PILE AIR ......... . 'jig: LOW POINT FOR CONDENSATE SCREENED OR DRAINAGE UNSCREENED COVER SULKING AGENT AIR AND SLUDGE PERFORATED PIPE BULKING FAN AGENT BASE NON-PERFORATED PIPE FILTER PILE SCREENED COMPOST AERATION PIPE sET-UP FOR INDIVIDUAL AERATED PILE AIR AIR SCREENED OR FILTER PILE UNSCREENED, SCREENED COMPOST COMPOST SLUDGE AND SULKING AGENT PERFORATED PIPE EXHAUST FAN DRAIN FOR CONDENSATES CONFIGURATION OF INDIVIDUAL AERATED PILES SOURCE: "Process Design Manual for Sludge Treatment and Disposal", USEPA 625/1-79-001, September 1979 41 FIGURE 3 4 EXTENDED AERATED'PILE- PAD AND PIPE OEFOnE ADDITION UNSCREENED COMPOST OF WOOD CHIPS AND COMPOST COVER PERFORATED AERATION PIPE TEE CONNECTOR WATER rJONPIERFORATED TRAP 4" OIA. PIPE BLOWER ODOR FILTER PILES DESIGN EXAMPLE EXTENDED AERATED PILE CONSTRUCTION COMPOST UJXTUAI TO MQ ED .1 CO-:?11.1D z S a 21 CONFIGURATION OF EXTENDED AERATED PILE SOURCE: "Process Design Namual for Sludge Treatment and Disposal", USEPA 625/1-79-011, September 1979 w //S 42 Confined or In-Vessel Composting Systems The major advantage of this type of system is the limited area per ton required to effect composting. In-vessel systems are-much more capital intensive and mechanized than windrow or aerated pile systems. The types of in-vessel systems available are as varied as the number of manufacturers producing them. All accomplish the composting process within a closed container to minimize or eliminate odors and reduce process time by using a high degree of operational control. Individual systems differ primarily in process control and materials handling methods. As with the previously described processes, the process control parameters are temperature, exhaust gases, and moisture. In the windrow process, gross control of oxygen is achieved by turning the piles; temperature and moisture are dependent variables regulated by oxygen concentration. In the aerated pile method, oxygen concentration may be finely controlled. However, temperature and moisture are still only indirectly controlled. With in-vessel systems, all process variables can be highly controlled. Within the relatively small vessel or reactor, virtually complete and continuous mixing (usually of a patented design) allows all process parameters to be closely monitored and controlled by means of aeration, moisture and heat addition. USEPA studies suggest that the limited detention times of in-vessel systems do not allow the composting process to reach completion.* If this is true then the curing periods of two to three months required to reduce volatile organic levels increase time and space requirements to those for unconfined sys tems. Figure 4 illustrates the components of a typical in-vessel system. A list of some manufactures of in-vessel systems is included as Appe ndix C. Potential Uses of-Compost The- composting process removes approximately 50 percent of the available nitrogen present in sewage sludge. Sludge is known to be deficient in potassium and phosphorus compared to commercial fertilizer. Therefore, the fertilizer value is reduced as a result of the composting process. Indeed, compost should not be considered a fertilizer but a soil amendment. However, there are significant benefits to using compost as a soil amendment: increased water retention capacity of sandy soils increased porosity of clay soils increased microbiological populations in soils increased availability of micronutrients provides for slow release (mineralization) of nitrogen, phosphorous and potassium. Process Design Manual for Sludge Treatment and Disposal, EPA 625/1-79-011, September 1979. 43 FIGURE 4 TYPICAL PROCESS FLOW SCHEMATIC OF A CONFINED COMPOSTING SYSTEM WASTEVVATER SLUDGE MIXING SULKING AGENT MECHANICAL COMPOSTER HEAT (REACTOR) (IF REQUIRED1 4 AIR SCREENING CURING E FINISHED. PRODUCT FIN ISHE PRO DUC _ SOURCE: "Process Design Manual for Sludge Treatment and Disposal" USEPA 625/1-79-011, September 1979 44- Composted sludge can be bagged and sold, or applied directly to land. Substantial increases in vegetable yields have occurred as a result of using composted sludge. Use of compost in land reclamation is well documented. S ome experiments have demonstrated that compost is effective in controlling plant disease and fungi. The increasing cost of peat moss makes the horticultural industry potentially a prime market for compost. Safety and Health-Aspects of-Composting The following information is summarized from 'Technical Bulletin: Composting Processes to Stabilize and Disinfect Municipal Sewage Sludges, EPA 430/9-81-011, July 1981,pp. 33-34 and Appendix B-1. Complete information can be found in Appendix D of this report. Employee Safety The usual rules of sanitation apply to compost facilities, such as washing hands before eating and before going home. Facility operators must provide showers and on-site clothing which is worn only at the facility. Dust conditions should be minimized. The facility should be located away from individuals susceptible to respiratory or other illnesses which might be brought about by the pathogens in sludge. This would include hospitals and nursing homes, for example. Health Aspects Facility workers are exposed to the risk of primary pathogens present in sludge and from secondary pathogens such as fungi and actinomycetes which produce an allergic response in lung tissue. The latter two grow during composting and usually infect only people with debilitated immune systems. However, the pathogens can cause an infection in an apparently healthy individual. Available studies indicate the risk to workers from primary pathogens is low. Infection can be prevented by proper sanitary procedures. Individuals in good health should not be infected by secondary pathogens. However, those predisposed to diabetes, asthma, emphysema or tuberculosis or who are taking certain medications may be more susceptible to infection. Table 22 lists pathogens generated during composting and their associated diseases. 45 TABLE 22 EXAMPLES OF PATHOGENS FOUND IN OR. GENERATED DURING COMPOSTING OF SEWAGE SLUDGE, TOGETHER WITH HUMAN DISEASES ASSOCIATED WITH THESE PATHOGENS. PRIMARY PATHOGENS 4 GROUP EXAMPLE DISEASE Bacteria Salmonella enteritidis Salmonellosis (food poisoning) Protozoa Entamoeba histolytica Amoebic dysentery (bl'oody diarrhea) Helminths Ascaris lumbricoides Ascariasis (worms infecting the intestines) Viruses Hepatitis virus Infectious hepatitis (jaundice) SECONDARY PATHOGENS Fungi Aspergillus fumigatus Aspergillosis (growth in lungs and other organs) Actinomycetes Micromonospora SP2 Farmer's lung (allergic response in lung tissue) SOURCE: Technical Bulletin: Compostina Processes to Stabilize and Disinfect Municipal Sewage Sludges, EPA 430/9-81-011, July 1981. 46 Composting-Facilities:-Case Studies General-Comments The following case studies resulted from telephone conversations with on-site chief operations personnel or municipal bureau directors. These discussions were held in early to mid-December 1985 and reflect the operational status of the facilities at that time. In discussing their operations, the contacts, in some cases, emphasized particularly noteworthy points, or several contacts mentioned items that most facilities seemed to share in common. Although to some degree these points may appear to be self-evident, they are included below as a list of general comments or guidelines. 1. The source 'of sludge cake should be located as near to the compost site as possible. Preferably, the composting facility should 'share the same site as the STP. If this is not possible, a location near each other is a high priority to reduce the cost involved in transporting wet sludge cake from the STP to the composting site. Having, the sludge cake source and STP in proximity also allows use of the STPs wet process train for treatment of leachate from the compost site and permits sharing of personnel and equipment. 2. When considering composting as a sludge management alternative, mun icipal officials and facility directors should visit as many operational sites as possible to become aware of the disadvantages and pitfalls of the various systems and equipment. This is.especially true as composting systems and equipment can be particularly site dependent. 3. All contacts confirmed that @dors exist with any composting operation. Most felt that the odors generated were, for the most part, confined to or in proximity to the site. However adverse conditions (thermal inversion, or warm, humid, or calm periods, ior example) caused odors to migrate and complaints to result. In addition, odors that operations personnel found acceptable were sometimes found objectionable by local residents. An adequate buffer zone should be provided between the compost site and residential areas. Two thousand feet seems to be an acceptable minimum, depending on local conditions (prevailing wind direction, average temperature, etc.). 4. Larger composting operations should consider hiring a professional consultant to do a marketing program. As marketing has traditionally not been a principal focus of municipalities, in-house expertise in this area is generally not available to municipal officals. Marketing is important to offset operational costs by sales of compost; a backlog of compost on site can create.odor and storage difficulties. 5. Costs presented here and in other sources should be considered approximate. Differences in cost accounting practices, amortization schedules, and site-specific factors make direct cost comparisons difficult without detailed analysis. 47 Composting Facilities:-Case Studies CASE 1 LOCATION: Scranton, PA OPERATOR: Scranton Sewer Authority PROCESS TYPE: Extended, aerated static pile CAPACITY- 8.5 tons per day SITE AREA: Ten acres presently; ultimately 25 acres DRIED SLUDGE CAKE: 23 percent solids SLUDGE DEWATERING: Vacuum filter BULKING AGENT: Wood chips ($8.10/yd) MIXING RATIO: 2:1 CAPITAL COST: Approximately $3 million (25 acre site) MARKETING: Compost sold for $5 per ton (approximately 4 cu. yd.) in bulk only DISCUSSION The Scranton system became operational in September 1984, replacing incinerators that were outmoded and inefficient. The second construction phase of the project is currently underway to expand the facility to 25 acres. The facility processes 12,000 to 13,500 wet tons of sludge per year at an average of 23 percent solids to produce 5,000 to 6,000 tons of compost per year at 40 to 60 percent solids. Compost is sold in bulk to nurseries, golf courses and municipalities for use in parks and other public lands. A feature unique to sludge management in Pennsylvania is the active involvement of Pennsylvania State University. Penn State provides specific site management guidance (soil requirements, and application rates, for example) and reduced rates for sludge and compost laboratory analysis. Scranton is relatively free of industrial discharges and, therefore, generates a "clean" sludge and compost. The composting site is located approximately 1,500 feet from a residential area and has virtually no odor problems. The composting operation employs three persons full time. Process control is based on temperature and oxygen monitoring. 48 CASE 2 LOCATION: Durham, NH OPERATOR: Town of Durham PROCESS TYPE: Individual aerated pile CAPACITY: 600 dry tons per year SITE AREA: 5 acres (10 acres including sewage treatment plant) DRIED SLUDGE CAKE: 19 percent SLUDGE DEWATERING: Vacuum filter BULKING AGENT: Wood chips ($6.00 per yd.) NIXING RATIO: 3:1 CAPITAL COST: $1.2 million MARKETING: Compost is "sold" to other Town departments for $6 to $7 per yd. DISCUSSION Durham became operational in the fall of 1980, and is considered one of the most successful composting operations in the East. The municipal waste stream is free of industrial waste, generating a "clean" sludge and Compost. Durham is the home of the University of New Hampshire. It has a win ter population of 24,000 and a summer population of 10,000. The compost facility is located on the STP site and was part of a $7.5 million treatment plant upgrade that included secondary treatment facilities and sludge handling facilities as well as thecomposting process. The compost operation employs two full time persons as well as a half time supervisor. 'The ultimate users of Durham's compost are other Town departments which are charged $6 to $7 per cubic yard. This rate provides a substantial cost savings to the Town over soil amendments used in the past, for example replacing $12 per cubic yard top soil. The composting facility is located directly adjacent to the treatment facility and approximately 700 to 800 feet from the nearest residence. odors resulting specifically from the composting facility are not judged to be a problem according to the facility operator. However, odor problems at the treatment plant have occurred. 0 49 CASE 3 LOCATION: Calverton, MD OPERATOR: Washington Suburban Sanitary Commission (public utility) PROCESS TYPE: Extended, aerated-static pile CAPACITY: 400 tons per day design; 200 tons per day currently being handled SITE AREA: 116 acres; 22 acres paved (concrete and asphalt) DRIED SLUDGE CAKE: 17 percent solids (average) SLUDGE DEWATERING: Various BULKING AGENT: Wood chips ($12.40/ton) 41 MIXING RATIO: Approximately 4:1 CAPITOL COST: $27 million (400 tons per day site) MARKETING: By contract with Maryland Environmental Services (state agency) under the trade name of COMPRO. Sold in bulk at $5.00 per cu.yd. to turf farms, nurseries and similar users, in 40 lb. bags to the general public DISCUSSION Operational in April 1983, the Calverton facility is called a "Cadillac" due to Its size and sophisticated equipment. For example, the plant features two 120 feet by 600 feet roofed, compost pads served by sophisticated air handling and odor control systems. Calverton is currently constructing its third compost pad and related facilities to bring the operation to its design capacity of 400 tons per day. Located within three miles of a population of 30,000, the facility has generated complaints of odors despite the higher technical odor control equipment. However, the operator feels that off-site odors are "minimal". The ultimate users of the compost product are reached via a marketing program by Maryland Environmental Services. Amarket for the facility's ultimate design capacity of 400 tons per day is believed to be available. The operation recovers approximately $100,000 per year through compost sales. 50 CASE 4 LOCATION: Hampton Roads, VA OPERATOR: Hampton Roads Sanitation District PROCESS TYPE: Extended, aerated static pile CAPACITY: 12 tons per day design, 7.5 tons per day actual SITE AREA: 5 acres; 1 acre of pads DRIED SLUDGE CAKE: 16.5 percent solids SLUDGE DEWATERING: Belt filter press BULKING AGENT: Wood chips ($20 to $22 per ton delivered) MIXING RATIO: 3.5:1 (by volume) CAPITAL COST: $1.7 million MARKETING: Landscaping and related industries; sold in bulk for $7.50 per cu. yd. ($6 per cu. yd. for 10 cu. yds. or more) DISCUSSION The Hampton Roads plant commenced operation in October 1981, and composts sludge cake from three sewage treatment plants within the sanitation d i s t r i c t .The faci lity is producing under capacity due to the excessive wetness of the preprocessed sludge. Design called for 20 percent cake solids, while actual cake solids average 16 to 17 percent solids. The Hampton Roads operation claims minimal odors and attributes this to maintaining moisture levels at 60 percent or less and providing for aeration during curing and storage periods. Marketing is handled directly by the sanitation district under the leadership of a full time agronomist. Compost is in demand and there is a market for all that can be produced. 51 CASE 5 ,LOCATION: Denver, CO. 40 OPERATOR: Denver Metropolitan Sewage District #1 PROCESS TYPE: Aerated windrow CAPACITY: 105 tons per day design; 70 to 75 tons per day currently handled SITE AREA: 23 acres; 17 acres under cover DRIED SLUDGE CAKE: 20 percent solids SLUDGE DEWATERING: Centrifuge BULKING AGENT: Wood chips ($20-$25/ton, softwood, no screening operation) MIXING RATIO: 2:1 CAPITAL COST: $13 million MARKETING: Landscaping and related industries; sold for $6 to $8 per ton; a bagging operation and aggressive marketing program is planned for 1986 DISCUSSION The Denver facility is in partial operation and under construction for full sea le operation scheduled for March or April 1986. The Denver operation is rel atively unique in the application of the dual utilization concept: land application and composting. Basically, this amounts to land spreading liquid sludge when climatic conditions permit and composting sludge during adverse conditions. Land application is the preferred alternative due to the lower operational cost ($60/ton for landspreading vs. $75/ton for composting). Denver's compost is rated "Grade V by the Colorado Health Department. This is the highest grade of classification, making the compost suitable for all agronomic uses including crops for direct human consumption. The Denver facility is located in an industrial area within one-quarter mile of a residential area and within 1.5 miles of a densely populated area. No odors emanate from the composting facility. In part, this may be due to the fact that composting is confined to the colder periods of the year. 52 CASE 6 LOCATION: Cape May, NJ OPERATOR: Cape May County Municipal Utilities Authority (not-for-profit public utility) PROCESS TYPE: In-vessel (Purac Engineering Inc., subsidiary of ABV-Sweden) CAPACITY: 12 tons per day design; 20 tons per day actually handled SITE AREA: 3 acres DRIED SLUDGE CAKE: 20 percent design; 30 percent (average) actual SLUDGE DEWATERING: Belt press BULKING AGENT: Sawdust NIXING RATIO: 0.2 to 0.3 parts sawdust: 1.5 parts recycled compost: I part sludge cake CAPITAL COST: $10 million ($5 million for site development, $5 million for composting facilities) MARKETING: Since the facility has been operational just over a year, marketing has not begun; compost is being stockpiled DISCUSSION Operational on April 29, 1985, this facility is unique in its ability to process approximately 160 percent of its designed capacity. Facility .operators attribute this capability,to the lack of moisture in the preprocessed sludge cake (65 percent to 75 percent actual as opposed to 80 percent design) and the high level of volatile solids (VS) present in the sludge (70 percent design VS as opposed to 85 percent actual VS). The operator commented that "this high volatility causes the sludge to dis appear"! The operator also reported that a water spray modification was added to handle the abnormally dry sludge. The reactor vessel consists of two rectangular stages: stage one is 30 feet by 55 feet long, stage two is 300 feet by 45 feet long. Stage one can be operated alone or in series with stage two. Similar facilities are under construction in Fort Lauderdale and Sarasota, Florida. The facility processes an average of 20 tons per day of sludge from four sewage treatment plants treating a total of 45 to 50 million gallons a day. An absence of industrial dischargers produces a clean sludge and, consequently, a clean compost. Potential markets for Cape May's compost include sod farms, nurseries and landscapers. 53 CASE 6 (continued) Although the process permits 100 percent of the exhaust gases to be captured, the facility, one-half mile from.a residential area, has had odor problems. To control odors, the existing single stage sulfuric acid wet scrubber is being expanded to include a second stage scrubber using caustic soda and an oxidizing agent. Another problem at this facility, mechanical in nature, has been with the use of drag chain conveyors for moving sludge cake. This section of the process is under redesign to replace this type of conveyor with a more suitable sludge conveyor device. Parking space is inadequate and road access is deficient. 54 CASE 7 LOCATION: Windsor, Ontario, Canada OPERATOR: Hearn and Sons Trucking (contract operator) PROCESS TYPE: Extended, aerated static pile CAPACITY: 110 tons per day SITE AREA: 7 acres DRIED SLUDGE CAKE: 27 percent solids SLUDGE DEWATERING: Centrifuge BULKING AGENT: Shredded rubber tires and wood chips MIXING RATIO: one part rubber:2 parts wood chips: one part sludge CAPITAL COST: $1 million (US) MARKETING: Current use is for landfill final cover and parks and recreation facilities DISCUSSION Ope rational since May 1977, this facility has some ratherunusual features: in-house design, contractor operated, a large amount of covered site area, use of shredded rubber tires as a bulking agent, and a contractor-designed screening device. The basic facility was designed by City of Windsor employees in cooperation with the City's contract operator who implements modifications as needed in what could be termed an "evolutionary process". The City bids out the operation on a five year contract based on tons of sludge cake processed. The current contract price is $15 per metric ton ($12 per metric ton sludge cake plus $3 per metric ton bulking agent) or approximately $67/dry ton (US dollars and tons). The contract operation is perferred because it eliminates the high cost of the City's unionized labor. Although the compost pads are not covered, a covered mixing building (8,000 square feet) and a drying structure (roof and three sides, 12,000 square feet) allow the finished compost to remain relatively dry after processing. The bulking agent mix consists of recycled remnant furniture hardwood chips and shredded rubber tires. The shredded rubber tires are available in Detroit from Uniroyal Tire ($13.33 US per cu. yd.) specified as 2" x 3" plus 10 percent size variation. At least one source indicated that heavy metal problems may. be associated with the use of shredded rubber tires. Windsor claims no such problems will be encountered provided that the tire pieces are clean cut, with no metal belting protruding from the rubber. 55 CASE 7 (continued) The contractor-designed screeening device is basically a modified, high capacity sand and gravel separator using a rubber mesh. Recovery rates of hardwood chips are claimed to be as high as 93 percent and losses of shredded rubber less than I percent. Although no aggressive marketing program is' being undertaken, the City has saved approximately $1 million in landfill cover costs. The compost is currently available on site free of charge although the City is ultimately interested in sale of the finished compost. Presently, the City does not apply the value of the compost to offset operational or capital costs. The faci lity receives sludge cake from its 30 million gallons per day (US, dry weather flow) sewage treatment plant. The composting site is within 1,100 feet of a residential area and receives about three to five odor complaints per year. The facility operator recommends a buffer zone of approximately 2,000 feet, however, to compensate for odor problems.- 56 CASE 8 LOCATION: Plattsburg, New York OPERATOR: City of Plattsburg (owned by Clinton County) PROCESS TYPE: In-vessel (Fairfield) CAPACITY: 34 dry tons;170 wet tons ultimately (design capacity) 20 dry tons current sewage treatment plant production SITE AREA: 14.7 acres (process and storage) DRIED SLUDGE CAKE: 20 percent solids SLUDGE DEWATERING: Belt press (four 2-meter presses), BULKING AGENT: Sawdust (softwood) MIXING RATIO: 1:3 sludge:sawdust ($20 plus per ton delivered) CAPITAL COST: $15 million MARKETING: Giveaway program, not developed DISCUSSION This facility features two parallel compost trains of 17 dry tons each. The Fairfield digestors are 115 feet in diameter and 10 feet deep. Both tra ins are equipped with sodium hyprochlorite wet scrubber systems for odor control. The site has a covered sawdust storage area and an open area for six months' storage of finished compost. The composting plant is remotely located, accessible by a one-mile road. 57 Costs of Composting Information on costs of composting is difficult to obtain because: 0 Cost accounting procedures among municipalities cause service costs to be charged inconsistently, i.e., dewatering costs can be sewage treatment costs or composting costs. 0 Transporation costs for taking the sludge to the composting site and taking the compost to the utilization site have been shown to be significant and highly site specific. 0 Cost and system requirements for bulking agents are site dependent as well as dependent on individual sludge characteristics. A cost analysis for the prec'eeding case studies is shown in Table 23. These costs are approximate. Summary Composting as a sludge management alternative is not an ultimate disposal option, but only an intermediate stage in sludge disposal. Marketing is the most significant factor in the success of any composting operation. Whi le sale of composted materials can be a factor in offsetting operational costs, income from this source is . felt to be highly variable and site specific and, in general, does not offer significant cost reduction. In EFC's evaluation, sale of compost merely performs the service of disposing of the composted material without added cost. A s ignificant problem with the operation of composting facilities continues to be the generation of odors. This is particularly a problem with open or unconfined (windrow and static pile) systems. However, odor problems have been encountered with in-vessel systems as well. As there are currently only three fully operational in-vessel systems in the United States (Portland, OR; Wilmington, DE; and Cape May, NJ), experience here, as well as information on cost of operation, marketing success, reliability, and other factors is inconclusive. It appears that the only possibility for implementing a composting facility on a large scale in the mid-Hudson region would be an in-vessel system, unless a substantial site could be located to provide a large, permanent buffer against surrounding residential development. In-vessel systems, while requiring a much smaller area for an equivalent amount of sludge capacity, have much higher associated costs. Their ability to mitigate odor problems is unproven in the United States due to a lack of operational experience. 58 TABLE 23 COST ANALYSIS OF COMPOSTING AT VARIOUS FACILITIES CAPACITY' 0 & M COST CAP. COST3 TOTAL COST REQUIRED AREA CAPITAL PROCESS (DT Sludge/yr.) FACILITY TYPE* Sludqe Compost ($/DT Sludge) .($/DT Sludge) ($/DT Sludge) j(AA!EeAS) 1(ft.2/DT Sludge/yr.) 0/DT Sludge/yr.) Scranton, PA XSP @,105 2,750 108.00 104.00 212.00 10 140 966.00 Durham, NH ISP 600 unknown 116.00 216.00 332.00 5 363 2,000.00 Calverton, MD XSP 12,410 8,250 268.00 20.00 288.00 116 407 1,088.001 Hampton Roads, XSP 2,738 4,107 126.00 42.00 168.00 5 80 621.00 Ln VA Denver, CO AW 26,463 54,750 75.00 37.00 112.00 23 38 339.002 Cape May, NJ IV 4,380 unknown 63.00 247.00 310.00 3 30 1,142.00 Windsor, ONT XSP 10,840 5,420 67.00 3.00 70.00 7 28 92.00 *XSP = extended aerated static pile ISP = individual aerated static pile AW = aerated windrow IV = in-vessel 1at 400 TPD design 2at 105 TPD design 3Note: Capital cost per dry ton is based on amortization of capital cost over 20 year period at 9% interest. This cost was computed for comparison purposes only due to the fact that actual data was not available from individual sites. LAND APPLICATION Introduction Land application is a process by which sludge and septage are injected bel ow or on the surface of land in a manner which benefits the soil or crop and does not cause any negative environmental impacts. Compared to most other management alternatives, except landfilling, it is a fairly simple process. An uncontaminated sludge properly applied to an appropriate site will benefit from the active flora and fauna present in the soil which biologically reduce the complex substances present in sludge to simple and in most cases, harmless substances for enrichment of the soil. USEPA studies estimate that as much as 40 percent of the sludge produced in the United States is applied to land.* Where a land application program is consistent with regulatory guidelines and crop needs, sludge and septage f rom treatment plants can be managed in a cost effective and environmentally safe manner. New York State Department of Environmental Conservation regulations restrict land application programs to utilization functions. Thus, a land application program which.results only in the disposal of sludge is not permitted. Some benefit other than merely cost effective disposal must be demonstrated. Use of sludge and septage on land falls into three basic catagories: Agricultural: sludge is applied at specific rates to satisfy a portion of the fertilization requirements of a given crop. Silvicultural: sludge is applied to increase forest productivity. Land Reclamation: sludge is applied to revegetate land which has been dis turbed as a result of such activities as strip mining or landfilling, or on land with marginal soil productivity. Application Methods The generally practiced method of applying sludge to land is to truck it in sol id or liquid form from the sewage treatment plant (STP) and unload it at the land application site either to an application vehicle or to a storage structure of some type. While sludge may be hauled from the STP to the landspreading site by the application vehicle for short distances, this practice is not recommended. Application vehicles are designed as slow moving, low geared vehicles with high flotation tires and limited cargo capacity (approximately 2,000 gallons) for mobility in field operations. Hauling vehicles are designed to carry greater cargo loads (approximately 6,000 gallons) over paved roads at much higher speeds. Process Design.Manual for Land Application of Municipal Sludge, EPT--625/1-93-016, October 1983, Page 1-1. 60 Application vehicles can apply sludge as liquid or as dried sludge cake. The decision to land apply sludge as a liquid or solid is site specific based on economic considerations related to hauling distances and dewatering costs. When liquid hauling costs approach dewatering costs, consideration should be given to using sludge dewatering facilities. Generally speaking, liquid sludge can be more easily applied than dried sludge because it can be readily pumped from one vehicle to another and to and from storage lagoons. Dewatered sludge cake may also be transferred between vehicles but may require larger equipment like front end loaders or complex materials handling systems. Sludge cake is sprea d on land surface by the application vehicle and later incorpor 'ated into the- soil by discing or plowing with farm equipment. Liquid sludge may be applied in a similar manner or may be directly injected under the land surface (subsurface application) using specialized equipment or some types of conventional farm equipment such as ammonia applicators. Subsurface application is more acceptable to the public which is concerned about odor problems. Where runoff conditions may occur, dewatered sludges allow much higher application rates before runoff becomes a problem. Subsurface injection, however, if properly applied, produces almost no runoff. These are the advantages of each method. Dewatered Lower transportation costs Handled with conventional municipal equipment (front end loaders, dump trucks) Less storage capacity required at STP or application site Liquid More plant nutrients available (a large precentage of the sludge nitrogen content is lost during dewatering) No dewatering cost May be transferred using vehicle mounted pumps Less,chance of odor problems o Less labor required when subsurface injected 61 Dual Utilization The beginning of this section describes the relative simplicity of land application as opposed to other management alternatives. In terms of the regulatory and environmental constraints, however, land application may be one of the more complex management alternatives. One key regulatory constraint prohibits application of sludge to frozen or snow-covered ground. In New York State, this effectively prohibits land application for approximately four months of the year. During this time, sludge must be alternatively managed. The possibilities are limited to dual utilization or extensive storage facilities. Dual utilization uses two different management options each fully implemented on a part-time basis. The composting section of this report briefly describes the City of Denver's dual utilization program incorporating both composting and landspreading. Economic considerations make land application the preferred option for Denver where winter conditions preclude landspreading but do not interfere with composting activities. The advisability of storing sludge for four months is questionable. Storage is frequently done in connection with small facilities (less than one million gallons per day) which often use drying beds as a drying and stabilization process. Since freezing conditions preclude drying, sludge must be stored in digestors or holding tanks during winter months. Digestors frequently lack adequate capacity for storage, and operational problems caused by solids backlogs may occur. Because storage capabilities are marginal even at smaller facilities, to suggest a similar approach on a regional or county-wide basis may be inappropriate. If a land application opt ion is chosen, a second major management alternative may be required for approximately four months. Sludge Storage With.Dual Utilization An appreciable amount of storage capacity must be provided to allow proper management of any land application program. Reasons for storage include fluctuations in sludge production rates, adverse weather conditions, equipment malfunctions, and agricultural cropping patterns or other site requirements. If sludge were to be stored at five percent solids, approximately 4,800 gallons of capacity would be required for each dry ton of sludge produced. Using a factor of 0.5 dry tons produced for each one million gallons of sewage flow treated, 2,400 gallons of storage capacity would be required for each million gallons of sewage treated. Going one step further, 120 days per year (four months) storage would require 288,000 gallons per year (38,500 cubic feet per year) for each million gallons per day of sewage treated. 62 Review of Recent USEPA-Sponsore&Studies During the past 15 years, the US Environmental Protection Agency (USEPA) has sponsored numerous studies and pilot projects on various aspects of land application of sewage sludge. One recent study entitled "Application of Municipal Sludge on Energy Crops: A Feasibility Analysis" (EPA-600/2-83-095, September 1983), evaluated the use of sludge on marginal land to produce a woody biomass. Essentially, this involves adding sludge to soil on which is grown a crop used as an energy source (for example, trees, or plants) which is digested to produce biogas. While the study determined that such a program would not yield a profit because planting, harvesting and, other program activities roughly equalled revenue from product sales, a credit from energy crop sales and from not using more costly options reduced disposal costs by up to 50 percent compared with landfill or incineration alternatives. These are the highlights of the summary and conclusions of the USEPA report: 1. S1 udge disposal through a wood energy crop program costs significantly less than other, more traditional, disposal alternatives, about 50 percent lower than incineration or landfilling. 2. Where such programs can serve population centers of approximately two million, production of electricity from the woody biomass becomes economically feasible. 3. Where the population center served approaches five million, ethanol production from sludge-grown sugar crops becomes feasible. 4. Ethanol production from sludge-grown grain crops is not economical for population centers less than 50 million. 5. While more of a return results from using sludge to grow agricultural crops rather than energy crops, energy crops minimize many of the risks associated with agricultural use, such as heavy metals, toxics and other public health considerations. In addition, the benefit or value to be obtained from wood energy is more stable and predictable than that from agricultural crops which are subject to varying weather conditions during the growing season and fluctuating annual prices for farm products. 6. For populations of 50,000 to 200,000 the capital investment is significantly lower for the energy crop method than for incineration. For population centers larger than 200,000, the energy crop approach becomes less attractive due to the costs involved in transporting by fixed pipeline. 63 7. Sizeable reductions in energy consumption are possible when an energy crop program is favored over incineration or laridfilling. Less. fossil fuel is consumed and a clean biomass fuel is produced. 8. When the biomass is used to produce electricity, as opposed to direct use for process heat or other uses, the energy balance still favors the energy crop approach. 9. Land requirements for implementing an energy crop approach are relatively small, and marginal land may be used. Thus, such sludge disposal would not encroach on land areas presently used or reserved for agricultural purposes. 10. The environmental benefits of this approach are: * a perpetually renewable energy source of low sulfur content is generated which does not affect the carbon dioxide balance in the atmosphere & land used for such a program will increase in value by becoming more fertile * heavy metals and toxics problems are significantly reduced. In the USEPA study, "Demonstration of Acceptable Systems for Land Disposal of Sewage Sludge" (EPA - 600/2-85/062, May, 1985), by the Ohio Farm Bureau Development Corporation, Columbus, Ohio, management systems are demonstrated which would minimize the potential adverse impacts of land app lication of sludge to farm lands and rural communities. Some highlights of this study are: 0 The study involved a large number of farmers and sites so the general public would not identify a particular farm or neighborhood as the sludge disposal site. 0 Public meetings and field days were held and community leaders consulted to make the public fully aware of the scope, objectives, and safety of the program. The residents of Ohio supported the concept of applying sludge to farm land as long as odor problems were minimized, nuisance situations in transporting and handling the sludge were avoided, and the metal content of the sludge was maintained at reasonable levels. 0. Sludge was applied at a rate to meet the nitrogen or phosphorus requirements of crops. This method used the nutrients in the sludge efficiently and minimized the potential for surface runoff and groundwater pollution. The level of nutrients applied was comparable to fertilizer applications on land not treated with sludge, thereby reducing the pos sibility of damage from unwanted metals or organics. For these reasons, the public approved the program. 64 0 A rapport develo ped between the people involved in spreading the sludge and the farmers who received the sludge. This is of utmost importance. A management program requires someone versed in agronomy to serve as a liaison between farmers and the sludge generator. This individual would discuss with the farmer the nutrient value of the specific loads of sludge, present and discuss monitoring data 'on the heavy metal content, and present a contract to farmers which would define the working relationship between the farmer and sludge generator. In general, this person would try to troubleshoot and maintain a good relationship between farmers and sludge generators. 0 Careful monitoring of the quality of the sludge and care to produce a well stabilized, odor free sludge are important management requirements. Odors occur when sewage plants are functioning improperly. The disposal of these sludges on land must not be considered a necessary emergency procedure which the public simply must accept. . A plan for such situations should be worked out ahead of time. At a minimum, odorous sludges should be incorporated into the soil as they are applied to the land. 0 Health risks were not significant when sludge was applied at low rates, using the management systems in this study. The risks of respiratory illness, digestive illness, Salmonellae, exposure to pathogenic organisms or general symptoms were not significantly different between sludge and control groups. Similarly there were no significant differences in the health of domestic animals on sludge and control farms. Viral infections among household members were observed. There was no significant difference in frequency of viral infections between sludge and control groups. The exposure of rural residents to sewage sludges did not significantly affect their fecal cadmium levels. 0. An economic analysis of landspreading was completed. The analysis was prepared in a computer format so the specific conditions of a given community could be quickly evaluated. 0 Laboratory studies tracked the effect of pH on the ability of plants to extract harmful cadmium from soils to which sludge had been applied. The movement of cadmium from. sludge-treated soils into the food chain is a concern. Cadmium will migrate when soil pH drops. If it is extractable through plants, it will enter the food chain. The studies determined that the extractability of cadmium in sludge soils increased dramatically as the pH dropped below 6.0. 65 Potential for Implementation of Land Application in the Seven County Region Approximately 35,000 dry tons per year of sludge and 10,000 dry tons of septage are generated regionwide * Using a conservative application rate of two dry tons per acre, less than 25,000 acres would be needed to land apply the total amount of sludge and septage generated in the region. Information supplied by the New York State Department of Agriculture and Markets indicates that the region contains 462,900 acres of farmland, of which 270,400 acres are actually crop and pasture lands as shown: County Farmland (acres) Crop/Pastureland(acres) DUTCHESS 140,800 78,400 ORANGE 131,100 87,300 PUTNAM 11,100 5,800 ROCKLAND 1,600 1,200 SULLIVAN 78,000 39,000 ULSTER 89,600 53,300 WESTCHESTER 10,700 5,400 TOTAL: 462,900 acres 270,400 acres Using the land requirement of two dry tons per acre, less than 10 percent of the available cropland would be used in a program that would land apply the total sludge and septage generated in the region. - 1: Section 4 discusses regulatory constraints for land application programs. Sludge rated "C" is prohibited from land application or compost utilization, "D"-rated sludge may be used at "dedicated" sites only (not cropland), and only "A"-rated sludge is acceptable for application to cropland. In general, sludge -quality information provided to EFC by the seven counties was insufficient to adequately characterize sludge quality with confidence. Sludge generators with an apparent contamination problem have sampled extensively to verify and determine the level of contamination. Many treatment plants have no data on sludge quality and others have one or two analyses only. The "A"-rated and unrated quantities of sludge shown in Table 24 may be amenable to land application. The quality of the sludge would have to be ascertained prior to using it for landspreading. 66 TABLE 24 SLUDGE AVAILABLE FOR LAND APPLICATION "All Rated Unrated Total Sludge No. of Sludge No. of Total No. 0f County (Tons*) STPs (Tons) STPs Tons -STPs DUTCHESS 1,670.9 6 1,431.6 9 3,102.5 15 ORANGE 749.5 7 3,072.7 30 3,822.2 37 PUTNAM 37.5 1 104.7 25 142.2 26 ROCKLAND 0 0 579.7 3 579.7 3 SULLIVAN 25.0 1 12421.6 17 1,466.6 18 ULSTER 644.0 3 637.3 11 1,281.3 14 WESTCHESTER .3,469.0 4 3,964.7 8 7,433.7 12 TOTAL 6,595.9 22 11,212.3 103 17,828.2 125 tons tons tons Dry Tons 67 No quality data whatsoever is available from the counties or other sources on the 10,592 dry tons per year of septage generated in the Hudson Valley. USEPK stud-ies of septage indicate that mean values of contaminents fall below EPA regulatory limits (see Table 25). It is probable, therefore, that contaminants in septage generated in the seven counties are also within regulatory standards. The total quantities of both sludge and septage available for land application as well as acreage requirements are shown in Table 26. EFC is assuming that the "unrated" sludge and septage would qualify for land app lication. A land application program, however, requires a commitment of capital and other resources and should not be undertaken with the current data which is incomplete. Using the da'ta in Table 24, it does not appear that a land application program would yield benefits commensurate with the costs of implementing it because: 1. "A"-rated sludge accounts for only 15 percent of the total sludge and sep tage wastestream, hardly enough to be used as a major part of a regional solution. 2. Approximately half the "A" rated sludge is located in Westchester County. Westchester appears to have limited sites suitable for land application and is not centrally located in the region. Also, it may be politically difficult to site a land application program where 50 percent of the total waste stream will originate from one county and only about 10 percent, or less, will originate in the county in which the site is located. If the total quantity shown in Table 26, 28,420 dry tons, is available (63 percent of the wastestream), this option becomes more attractive because an economy of scale can be achieved and a significant amount of the waste stream will be managed. It appears that land application may be viable in all counties except Rockland and Westchester where the ratio of land available to sludge generated makes this option appear inappropriate. On a regional basis, this option would need only slightly more than five percent of the total cropland available. It should be emphasized that EFC's recommendation is to land apply only clean sludge for its nutrient value. EFC does not propose that cropland be sacrificed for use as a dis posal site. Land application on cropland, where appropriate, should not create a conflict between the goals of disposal and agricultural use. For illustrative purposes, in a scenario where all sludge and septage generated in the region (approximately 45,000 dry tons per year) could qualify for land application, 22,500 acres would be required at a loading rate of two dry tons per acre. This option requires that approximately 10 percent of the cropland in the region be used for land application. While this option would never be used for the region's entire sludge and septage generation, this approach illustrates that large quantities of material may, with effective project management, be beneficially recycled using a small proportion of available cropland. 68 HEAVY METAL CONCENTRATIONS IN SEPTAGE COMPARED TO TYPICAL DOMESTIC WASTEWATER SLUDGESa Typical Suggested U.S. Design Domestic Value United States (5) (9-19) -Europe/Canada (4) (20) Sludge EPA Mean for Parameter i-verage Minimum maximum Average Minimum Maximum Ranges (28)b (5) Septage Al 4 8 2 200 --- --- --- 48 50 As 0.16 0.03 0.5 --- --- --- 0- 0.7 0.16 0.2 Ca 0.27 0.03 10.8 0.05 --- 0.35 0.1- 44 0.71 0.7 Cr 0.92 0.6 2.2 0.63 5.0 0.9- 1,200 1.1 1.0 Cu 8.27 0.3 34 4.65 1.25 15.0 3.4- 416 6.4 8.0 t-4 re 191 3 750 --- --- --- 200 200 %0 Ln Hg 0.23 0.0002 4 0.15 0.2 0- 2.2 0.28 0.25 Mn 3.97 0.2 32 --- --- --- --- 5 5 Ni 0.75 0.2 37 0.58 --- 2.5 0.5- 112 0.9 1 Pb 5.2 2 8.4 3.88 21.25 3.2- 1,040 8.4 10 Se 0.076 0.02 0.3 --- --- --- --- 0.1 0.1 Zn 27.4 2.9 153 38.85 1.25 90 79- 655 49 40 aValues expressed as milligrams per liter(mg/t.) bValues converted from micrograms per gram (mg/g) assuming total solids 40,000 mg/L. SOURCE: Handbook: Septage Treatment and Disposal EPA 625/6-84-009, Cincinnati, Ohio, October 1984. TABLE 26 ACREAGE REQUIRMENTS FOR LAND APPLICATION "A" RATED and UNRATED SLUDGE SEPTAGE TOTAL CROPLAND ACREAGE 1 2 COUNTY Dry Tons Dry Tons Dry Tons (Acres) REQUIRED- % DUTCHESS 3,103 4,321 7,424 78,400 3,712 4.7 ORANGE 3,822 1,768 5,590 87,300 2,795 3.2 PUTNAM 142 0 142 5,800 713 1.2 ROCKLAND 580 1,894 2,474 1,200 1,237 103.0 SULLIVAN 1,467 581 2,047 39,000 1,024 2.6 ULSTER 1,281 446 1,727 53,300 . 864 1.6 WESTCHESTER 7,434 1,582 -9,016 5,400 4,508 83.5 TOTAL 17,829 10,592 28,420 270,400 14,211 5.3% Tons Tons Tons Acres Acres 1. Acreage required at a loading rate of two dry tons per acre 2. Acreage required as a percent of total cropland in respective county 3. Figures for Putnam County are deflated due to inaccuracies in septage reporting. 70 Recommendations for All Counties 1. Initiate a six-month sampling and analysis program, in accordance with NYSDEC guidelines, to adequately characterize sludge quality at sites where such data is currently lacking or inconclusive. 2. Discuss with NYSDEC officials the advisability of conducting a sampling and analysis program for domestic septage. 3. Develop appropriate siting criteria and evaluate specific sites within the region to implement a sound management approach for a land application project. Municipalities should be actively involved during the criteria development stage. 4. Where sludge is determined to be "contaminated", an evaluation of the causes should be made. The cost efficiency of addressing the contamination problem at the source versus treating a contaminated sludge should also be evaluated. 5. Develop a detailed cost estimate for each generation and disposal site being considered for development. 6. Consider canvassing the region for potential "dedicated" sites that could be used for disposal of "D"-rated sludges. 71 OCEAN DISPOSAL Introduction ocean disposal of municipal sludge is accomplished by releasing it into designated areas of the ocean, either from vessels or through outfall pipes. Pipe discharge of sludge is presently not allowed under the federal Clean Water Act and is being phased out. Ocean disposal for communities near the sea has been a relatively low cost disposal alternative. The federal Marine Protection, Research, and Sanctuaries Act of 1972, which regulates ocean disposal, authorized the United States Environmental Protection Agency to select appropriate ocean disposal sites. Prior to 1981, the New York Bight (12 mile site) was designated. USEPA has permitted dumping at this site since 1981 only with the approval of federal district court. All ocean dumpers are on a phased program to move to a replacement site, known as the 106 mile site, located off the Outer Continental Shelf, 125 miles southeast of the entrance to New York Harbor and 132 miles off Atlantic City, New Jersey. Users must send all their waste to the 106 mile site by 1991. Site designation is based on proximity to beaches and the effect of disposal on the marine environment. Permits for sludge disposal are based on the volume and characteristics of the sludge and the availability and effect of alternative disposal methods. A permit to ocean dispose of sludge is granted only if the applicant can clearly demonstrate that no practicable alternative is available which has less impact on the total environment. USEPA selected the 106 mile site over the closer 12 mile site for several reasons. Its primary concern was the degradation of the water quality of the New York Bight (the section of the Atlantic Ocean within the bend of the coastline between Long Island and New Jersey). Although sludge disposal is not the only cause of the degraded condition of this area, it is a contributor to the problem which, USEPA determined, can be alleviated by moving the disposal site. Process @Barging municipal sludge to an ocean disposal site is relatively simple, accomplished by self-propelled sludge vessels or by sludge barges towed to sea by tug boats. The sludge is then either pumped or released by gravity at the disposal site. Initial dispersal of the waste is aided by turbulence in the wake of the vessel. Volatile hydrocarbons evaporate into the atmosphere, while grease, oil and scum remain on the water surface and may be transportated long distances by winds and currents. The remaining sol ids either settle to the ocean floor or are retained in clouds dispersed at various depths. Many contaminants are contained within fine particles and can accumulate below the ocean's surface, exposing the organisms in the area to contamination. 72 There is greater potential for dispersion of solids at the 106 mile site than at the 12 mile site. Although the 106 mile site has a permanent density stratification at about 650 feet, other hydrographic features inc rease dispersion and the transportation of materials out of the disposal area. These features include prevailing currents and large eddies that .break off from the Gulf Stream and traverse the site about 70 days per year. The 106 mile site has been used for the disposal of various materials since 1461. USEPA has not detected any long term adverse ecological effects from these activities to date. Safety and-Health Considerations. Hazards to public health from ocean disposal include bacterial contamination of recreational areas or ingestion of contaminated shellfish. Major concerns connected with ocean disposal include the accumulation of heavy metals and synthetic hydrocarbons in marine organisms, increased level's of pathogenic organisms, decreased dissolved oxygen levels, increased turbidity levels, and adverse effects to water quality, bottom sediments and marine organisms. Additional Considerations USEPA designated the 106 mile site in 1985, anticipating an end to ocean dumping in five years. This position seriously affects the viability of ocean disposal as a long term sludge management alternative. The increased round trip travel time to the 106 mile site, estimated to be 26 to 30 hours from Northeast coastal cities, may mean that additional sludge storage fac.ilities are needed. Adequate storage must be provided for times when dumping cannot be accomplished due to adverse weather conditions or other causes such as equipment malfunctions. Municipalities will have to redesign or modify ocean-going barges or vessels and dock facilities or else contract for barging services. Case Studies of Ocean Disposal A comparison of the cost for Boston, New York City and Westchester to dispose in the ocean is given in Table 27. Case studies for the three municipalities are also provided following the table. The ocean disposal alternative is least favored by USEPA. The permitting process is difficult and costly to a municipality. Although it is still possible to apply for an interim three year permit, there is no assurance that the currently designated 106 mile site will continue to operate after the present five year authorization. It would be prudent for any municipality applying for a new ocean dumping permit to have plans in place for land based alternatives, as not only would USEPA expect them in order to consider the temporary application, but the eventuality of closure of the 106 mile site would make such precaution mandatory. 73 TABLE 27 COMPARISON OF COSTS TO USE OCEAN DUMPING AT THE 106 MILE SITE FOR BOSTON, NEW YORK CITY AND WESTCHESTER Item Boston 2 NYC3 Westchester 4 Sludge Volume 29.3 million 99.4 million 15 million CU. ft./year Sludge quantity, 2,504 8,493 1,282 wet tons/day Dry tons/day, 75 255 39 at 3 percent solids Cost of Hauling $/Per cu. ft. $ 0.57 $ 0.13 $ 0.1025 $/wet ton $ 18.23 $ 4.17 $ 3.27 $/dry ton $607 $138 $109 Distance hauled, 275 106 120 miles (one way) Notes: 1. Calculated on the basis of sludge at three percent solids 2. Proposed tug/barge combination, 4,000 to 8,000 long tons (2,240 lbs.). Contract period: January 1988 to January 1991. Current Status: USEPA permit application withdrawn. 3. Tug/barge combination 1 15,000 tons. Began operation at 10 percent of total sludge output in May 1986. Balance. of output to be transferred by January 1988. 4. Tug/barge combination, 15,000 tons. Began at 100 percent of output (except for incinerated portion). Two year contract period, after which costs may change. 74 CASE STUDY - NEW YORK CITY LOCATION: New York, New York OPERATOR: NYC Department ofEnvironmental Protection Municipal Building New York, New York 10007 PROPOSED DISPOSAL METHOD: Ocean disposal of digested municipal sludge at the federally-approved 106 mile site. Now using 12 mile site with federal district court approval. QUANTITY TO BE DUMPED: 3. 1 mi 11 i on we t tons per year, equivalent to approximately 255 dry tons per day at three percent solids. Amount to increase upon completion of North River and Red Hook facilities. DISTANCE TRAVELED: The approximate distance is 106 nautical miles one way. HAULING FACILTY: Tug/barge combination; tugs to be under contract; barges under construction by NYC (approximately 15,000 tons capacity). COST OF OPERATION: As yet undetermined, subject to evaluation of bids. Early estimates indicate approximate cost of $250 per dry ton. PROPOSED PERIOD OF OPERATION: Ten percent of output shifted from 12 mile site in April, 1986. Balance of hauling to the 106 mile site* to be completed by January 1988, and is to continue until 1991. DISCUSSION: Originally mandated by an Act of Congress to cease all ocean dumping by December 1981, NYC got relief in Federal District Court which eventually resulted in the present plan to shift the dumping location to the 106 mile site. However, this arrangement may itself conclude in 1991 whe n the 106 mile site will be reevaluated by USEPA. NYC is joined in this act ion by nearby New Jersey localities and Westchester and Nassau counties, which together accounted for 8.3 million wet tons of sludge during 1983. The program is proceeding as follows. The existing self-propelled fleet of motorized sludge vessels started hauling to the 106 mile site in April, 1986. Meanwhile, contracts are to be let for construction of 15,000 ton barges, which will be used by contractors. The initial startup has been delayed because of personnel problems. Bids for the vessels have been received, and came in below engineering estimates. More specific information will be available after the contract is awarded. The existing self-propelled fleet will be used to transfer sludge within the harbor to ocean-going barges. It is apparent that Westchester County's low cost of approximately $107 per wet ton is not likely to be duplicated by NYC, as the need for inner-harbor transport and sludge handling adds considerably to the total cost. However, this may be somewhat offset by the use of the City's own barge fleet, rather than contracted facilities as are being employed by Westchester. 75 CONCLUSIONS: NYC is proceeding with a practical plan, rather than relying solely on litigation with the USEPA, as it has been doing until recently. It is still not entirely clear whether the City will eventually have to return to the land-based options that were espoused in the sludge management plan prepared by Camp Dresser and McKee in response to the December 1981 federal order, should public pressure result in the closing of the 106 mile site after 1991. If this be the case, land based technologies will be the only course of action for all municipalities in this region. 76 CASE STUDY: BOSTON LOCATION: Boston., Massachusetts OPERATOR: Massachusetts Water Resources Authority (MWRA) One Center Plaza Boston, Massachusetts 02108 PROPOSED DISPOSAL METHOD: Ocean disposal of digested sludge at federally approved 106 mile site. QUANTITY TO BE DUMPED: 600,000 gallons per day.of approximately three percent sludge, equivalent to 75 dry tons per day of primary digested sludge, originating from 435 million gallons per day of sewage from the Boston metropolitan area. DISTANCE TRAVELED: 275 nautical miles, one-way, 100 to 200 trips per year. HAULING FACILITY: Tug/barge combination, 1.1 to 2.1 million gallons capacity (4,000 to 8,000 tons). COST OF OPERATION: $50 million over the three year permit period, equivalent to $607 per dry ton of sludge, or $6.50 per year per resident (on the basis of cost per wet ton, figured at 70 dry tons per day, three percent solids, approximately $19 per wet ton). PROPOSED PERIOD OF OPERATION: Three years (January 1988 to January 1991). DISCUSSION: Boston applied for an ocean dumping permit in 1985 to satisfy a court order mandating it to stop polluting Boston Harbor with digested primary sludge discharges. The MWRA proposed to use a tug/barge combination over the 275 mile distance to the 106 mile site to dispose of approximately 900,000 wet tons of sludge per year. Barging was scheduled to begin in January 1988 and conclude in January 1991, approximately when the 106 mile site will be reviewed for redesignation by the USEPA. The Bos ton long range, land-based disposal facility is supposed to be operating in 1991, so MWRA needed only a three year special permit. Originally the cost to Boston of disposal was estimted at $19 per wet ton over a six year period (including lead time) representing about $.17 per 1,000 gallons of sewage, or $6.50 per capita per year. The $19 appears exorbitant compared to Westchester's quote of $3.20 per wet ton, but it should be kept in mind that the increased hauling distance (275 miles .compared to 106 miles for Westchester) more than doubles hauling costs. Also to be considered is the need for special docking facilities at Deer and Nut islands at a cost of more than $12 million. 77 USEPA Region II rejected Boston's application as incomplete. The City was supposed to have resubmitted its application, but recently notified USEPA that it would not.resubmit the permit request. The Boston MWRA problem parallels the seven-county situation in several ways: 1. Both are subject to regulatory constraints calling for sludge disposal within the near future with environmental controls that make for difficult and expensive choices. 2. Both are near enough to the 106 mile site to be a viable option. 3. Both are disposing of sludge in small enough quantities to make an application acceptable to USEPA on a quantitative basis. 4. Both can incorporate facilities, such as dewatering, which will make ocean disposal more economical. This will allow the future use of these facilities land based options, as they can be incorporated in the process chain. NOTE: 1986 amendments to the federal Clean Water Ac.t prohibit Boston from dumping at the 106 mile site. 78 CASE STUDY: WESTCHESTER LOCATION: Westchester County OPERATOR: Westchester County Department of Environmental Facilities PROPOSED DISPOSAL MET HOD: Ocean disposal of digested sludge at federally-approved 106 mile site. QUANTITY TO BE DUMPED: 30 million cubic feet at approxmately three percent solids over two yearcontract period. DISTANCE TRAVELED: The barge haul distance is 106 nautical miles, one way. HAULING FACILITY: Tug/barge combination, sizes up to 15,000 tons capacity. Contracted with offshore Transport Corporation, Bayonne, New Jersey. COST OF OPERATION: The cost of $0.1025 per cubic feet or $109 per dry ton of solids is projected. PROPOSED PERIOD OF OPERATION: The present two year contract for sludge barging starts in April, 1986. Westchester County intends to continue with ocean disposal at the 106 mile site for the five year period through 1991. OTHER SLUDGE DISPOSAL METHODS: The County now employs conventional sludge incineration at Ossining and New Rochelle and plans to install a fluidized bed-incineration facility-at Port Chester. DISCUSSION: The County has no present plans to improve docking facilities at Yonkers, or to dewater sludges in light of the favorable contract price and possible eventual abandonment of the ocean. There is presently no land based alternative planned for the Yonkers facility. 79 THERMAL REDUCTIOW Introduction Thermal reduction has been used to treat sludge since the early 1900s. Thermal reduction uses high temperature processes to destroy pathogens and reduce the quantities of sludge requiring disposal. Thermal reduction processes may be divided into incineration and pyrolysis. Heat treatment is generally provided as a pre-treatment process prior to thermal reduction. Incineration Incineration is the most common of thermal reduction processes. It is the actual burning of sludge. This combustion process converts organic solids to carbon dioxide and water vapor, while reducing the inorganics to an ash. The types of incinerators generally in use today are multiple hearth, fluidized bed, rotary kiln and cyclonic. Multiple Hearth Furnace The mutiple hearth furnace is the most common method of incineration practiced in the United States today. It is fairly simple in operation, reliable, and can handle fluctuating sludge materials and loadings. A section through a multiple hearth furnace (MHF) is illustrated in Figure 5. The MHF consists of a tall cylindrical combustion chamber with several ,ci.rcular hearths stacked one above the other. A centrally located cast iron shaft runs the full height of the furnace and supports two or four cantiievered rabble arms above each hearth. Each arm contains several rabble teeth that rake sludge spirally across the hearth, below the arms, as the arms rotate with the central shaft. Sewage sludge is fed at the periphery of the top hearth and then raked by rabble teeth toward the center to an opening through which it falls to the next hearth. Here the sludge is rabbled outward to the periphery and so on alternately down the furnace. Sludge and gas streams move countercurrent to one another, sludge passing down through the furnace and eventually becoming ash, and combustion air moving upward over each hearth and exiting as flue gas at the top hearth. Upper hearths are used for vaporization of moisture and cooling of the exhaust gases. Volatile gas and solids are burned in the intermediate hearths, while the lower hearths are used for combustion of ,slow burning compounds and cooling of the ash. Incineration temperatures for multiple hearth systems range froml,000 0F. on the top hearths to 1,6000F. to 1,8000F. on the middle hearths to 6000F. at the bottom. Sludge to be burned in the MHF must contain a minimum of 15 percent solids due to the evaporation capacity of the furnace. Generally, wet scrubbers and afterburners must be employed to meet required emission standards and eliminate odors. 80 FIGURE 5 SLUDGE INLET HEATED AIR INLET RABBLE ARM AT EACH HEARTH DRYING ZONE DRYING AIR OUTLET SEE FIGURE 6-f FOR OPTIONS COOLING ZONE'- RABBLE ARM DRIEO DRIVE SLUDGE 0 OIS%-.HARGE---' @OOLING AIR FAN TYPICAL SECTION MULTrPLE HEARTH DRYER SOURCE: Los Angeles County/Orange County Sludge Processing and Disposal, April 1977 L P. 7-3 81 As with all heat reduction systems, a considerable amount of ancillary equipment is required (see Figure 6). Fluidized Bed Incinerator The fluidized bed incinerator consists of a bed of sand into which sludge is introduced as shown in Figure 7. Air is blown into the area below the sand bed to fluidize the sand and sludge mixture. The combustion of sludge takes place in this expanded sand and sludge bed. The fluidized bed furnace operates at temperatures be7tween 1,300 0F. and.1,500 0 F. These temperatures incite the sand into a violent boiling action, thereby requiring no other mixing devices. The entering sludge dries and burns rapidly in this atmosphere. Most of the ash exits from the furnace in the exhaust gas. Like the MHF, fluidized bed furnaces require a substantial amount of ancillary equipment including wet scrubbers (see Figure 8). One major advantage of the fluidized bed furnace is that there are no moving parts. Rotary Kiln Furnace The rotary kiln furnace is not widely used for sludge incineration. It operates similarly to the multiple hearth in that sludge is dried in the upper area and burned in the lower region. Like the flash dryer, it has been used most widely for sludge drying but also has been applied to combustion of sludge with refuse. Operation of a rotary kiln dryer is described later on in this section. 82 SIIAFT C001 II,jr, AIH NOT 11FT011NED INDUCED DRAFT FAN PRECOULER- AND VENTURI S14AFT COOLING FURNACE HEAT BOILER AIR RETURN XHAUST RECOVERY EXHAUST BOILER WETSCRUBBER RJUDG E Opp RECOVERABLEHEAT ruo SCRUBBER WATER MULTIPLE HEARTH OD FURNACE SUPPLEMENTAL DRAIN FUEL RADIATION PRECOOLER AND VENTURI WATEI COMBUSTION AIR CONNECTED POWER ASH SHAFT NG AIR C- a A FLOWSHEET FOR-SLUDGE INCINERATION IN A MULTIPLE HEARTH FURNACE J. SOURCE: EPA Process Design Manual Sludge Treatment and Disposal, September 1979, p. 11-37 FIGURE 7 SIGHTGLASS N 99, 4 r EXHAUST SEE FIGURE 6-1 FOR OPTIONS PREHEAT BURNER SAND FEED FLUIDIZED THERMOCOUPLE SAND PRESSURE TAP SLUDGEINLET ACCESS DOORS t FLUIDIZING AIR INLET TYPICAL SECTION OF A FLUID BED REACTOR SOURCE Los Angeles County/Orange County Sludge Processing and Disposal, April 1977, p. 7-5 84 FURNACE EXHAUST GAS EXHAUST COMBUSTION AIR INDUCED DRAFT FAN RECUPERATOR WET SCRUBBER SCRUBBER VENTURI WATER BED COILS FOR 00 HEAT RECOVERY Ln (NOT USED IN DRAIN THIS ANALYSIS) RA IATION FLUID BED FURNACE do RECYCLE WATER ASH SUPPLEMENTAL FUEL SLUDGE FEED MAKEUPWATER AIR CONNECTED POWER Pd co - F -E @R C-V Y ED IN L . A Y"S' ,.,AT,.N "FLUID FLOWSHEET FOR SLUDGE INCINERATION IN A FLUID BED FURNACE SOURCE: EPA Process Design Manual Sludge Treatment and Disposal, September 1979, p. 11- 52 Co-incineration of Sewage Sludge and Municipal Refuse To achieve co-incineration, municipal solid waste and sludge are burned by a mutually compatible process. Only one co-incineration facility exists in New York, at Glen Cove, Long Island. It is a mass burn furnace in which sludge i s mixed with municipal solid waste in a ratio of approxmately I to 7. Technology for the express purpose of combined incineration of sewage sludge and municipal refuse is still evolving. There are presently four different approaches to co-incineration: 1. combustion of dewatered sludge in a refuse incinerator 2. combustion of pre-dried sludge in a refuse incinerator 3. use of refuse derived'fuel in a multiple-hearth sludge incinerator 4. use of refuse derived fuel in a fluidized bed sludge incinerator. All the major techniques for combined incineration have been tried in the U.S. and have experienced problems. over the past 30 years, 23 facilities in the U.S. have co-incinerated refuse and sewage sludge. Only one fac ility is currently operating on a regular commercial basis, 18 have shut down, and the remaining four have reverted to single purpose incineration. Six co-incineration facilities were being planned during the mid 1970s. Of these, only one is operating. One is still being considered, but plans for the remaining four facilities have been dropped. A variety of operation and maintenance problems have plagued virtually every co-incineration facility in the U.S. It has proved difficult to maintain combustion in refuse incinerators when partially dewatered sludge is added. Although thermal drying of the sludge mitigates combustion-related problems, the dryers themselves are subject to plugging, corrosion, and odors, as well as fire and explosion. Technical obstacles to burning refuse-derived fuel in conventional multiple-hearth or fluidized bed sewage sludge incinerators include ensuring the reliability of refuse preparation systems and controlling combustion. Planning and implementing new co-incineration projects in the U.S. is often hampered by institutional differences among groups responsible for disposing of sludge and of refuse. Whereas management authority for sludge is vested in centralized public bodies, the collection, transportion, and disposal of municipal refuse is 'usually managed by a combin4ton of decentralized public and private bodies. These institutional differences hinder the integration in municipal waste management programs necessary for the implementation of co-incineration facilities. Moreover, the criteria employed in siting a sludge treatment and disposal plant are essentially different from those used in locating a refuse incinerator. 86 Very little data is available on particulate emissions from combined incineration of sewage sludge and municipal refuse. Operating a multiple-hearth unit in a pyrolysis '(starved air) mode does not appear to offer any significant reduction of uncontrolled emissions when prepared municipal refuse is used for fuel. It is doubtful that all the various approaches to coincineration will have similar emission characteristics, although this is a topic deserving further investigation. Despite the general lack of technical success with co-incineration projects, the costs of combined incineration of sewage sludge and municipal refuse are still attractive when compared to the costs of burning these wastes separately. Co-incineration is also attractive from the standpoint of energy conservation. Thus, the incentives to co-incinerate are clear, yet until the various technical problems and uncertainties are overcome, little growth in the use of co-incineration can be expected over the next five years. Incineration of Dewatered Sludge in a Conventional Refuse Incinerator The oldest, simplest, and most direct method of achieving combined incineration is to burn partially dewatered sludge (i.e., 70 to 80 percent moisture content) in a conventional municipal refuse incinerator, depicted in Figure 9. The sludge can be fed separately into.the furnaceby either spraying it into the combustion chamber or by dumping it onto the grate. Alternatively, the sludge can be mixed with the refuse prior to entering the incinerator. Although mass burning has the advantage of simplicity, it has not proved very successful. The major problem encountered with this technique relates to combustion. Conventional incinerators usually provide insufficient time for the sludge to burn completely. In addition, too little heat is generated from the burning i@efuse to evaporate the moisture and combust the sludge. These problems are compounded by difficulties in distributing the sludge evenly within the furnace. For the most part, co-incineration through mass burning has proved unsuccessful both in this country and in Europe, although two future projects in the U.S. are expected to use it. Co-incineration of Pre-dried Sludge in a Conventional Refuse Incinerator As a means of overcoming the problems associated with burning sludge directly in a refuse incinerator, a number of facilities have installed systems to dry sludge to less than 20 percent moisture content before it enters the furnace. A wide variety of different drying syste@is have been employed. Direct contact dryers, heated by flue gas, steam-heated rotary dryers, flash evaporaters, spray dryers, and.multi-effect evaporators have all been used in the past. Dried sludge is then mixed with the refuse at a ratio of approximately 10 parts refuse to one part sludge and fed into the incinerator. 87 FIGURE 9 CODISPOSAL SYSTEM PROCESS SCHEMATIC & MATERIALS' BALANCE rc @OCG 225 ur OCG BRS RR8 62.5 62.5 rs WCC 112 .5 ur, ea. _WCC rs A 12.5 ds 2 s 12.5 ds 12.5 ds S C SHT 12.5 ds 20% a SB SB 125 ea. ur IN ds 44 SBC Sec S C 50 50 AL c a 756 so. ca cs A 16600 *17 MBFW/ OFA & UFA -1600 *F 47 fr WCW 23.5 f r WCW SRC a- SRC a- MDS X R S DR S MWT 857 c9 so. -900 KW 44 Ira WHCB 242.4 a to $3 A RG 2500 LILCO 0 to ferrous SEG 00 --40- I : : @@KSW 1000 landfill scrap dealer FC FC 600 p fo 489*17 KW to to 242.4 bfW -600 XW ESP E T-0- 25,080 A ccW 857 c 857 eg 25,080 IDF I DF A KEY ccw + 271 F C9 to airnasoers MAJOR EQUIPMENT PROCESS MATERIALS QUANTITIES & SYMBOLS BRS - Bulky Refuse Shear bfw - boiler feed water All quantities in tons per day except kilowatts DRS - Double Reciprocating Stoker ca - combustion air ea. - each ESP - Electrostatic Precipitator cg -combustion gas F - Fahrenheit FC - Flyash Conveyor cs - centrate sludge KW - Kilowatts IDF - Induced Draft Fan ccw - condensor cooling water p - gage pressure (psig) MBF - Mass Burning Furnace ds - dewatered sludge rc - radio control MCT - Muld-stageCondensing Turbine fa - flyash s - solids (sludge) MDS - Magnetic Drum Separator fm - ferrous metals wl - with MINT - Metal Washing Trommel fr - furnace residue A - Wastewater Treatment Plant OCG - Overhead Crane & Grapple fra furnace residue ash 0 - Codisposal/Energy Recovery OFA - Overfire Air rs raw sludge Facility RG - Reduction Gear ss saturated steam LILCO - Long Island Lighting Co. ROC - Roll-off Container ur unprepared refuse RRB -Refuse Receiving Bin RWS - Refuse Weighing System SBC - Sludge Belt Conveyor SC - Sludge Centrifuge SOURCE: mmb Glen Cove Corporation SEG - Synchronous Electric Ge6erator SHT - Sludge Holding Tank _5RC - Siftings & Resid ue Conveyor - Steel Stack --)SC - Steam Surface Condensor UFA, - Underfire Air WCC - Water-coded Chutes 88 WCW - Water-cooled Walls WHCB - Waste Heat Convection Boiler This method has been relatively successful. Pre-drying mitigates the combustion problems associated with the.use of only partially dewatered sludges, such as loss of BTU value and accumulation of non-combustible mat erials at the bottom of the incinerator (slag). Also, separation of the drying process from the combustion process simplifies furnace operations. Nonetheless, this technique has not been entirely devoid of problems. A major difficulty has been the prevention of rapid corrosion in the dryers. Clogging and general handling problems have also been encountered with the dried sludge. Odors given off by the dryers (particularly direct contact dryers) has been another obstacle. Flash evaporators are unattractive because of the potential for explosion. Nonetheless, the majority of facilities currently coincinerating in Europe, as well as the only commercially operating plant in the U.S., can be classified as pre-dried type units. Combustion of Refuse in a Multiple-Hearth,Sludge Incinerator In this arrangement, prepared municipal refuse is used in place of fossil fuels for burning sludge in a multiple-hearth furnace (MHF). The raw refuse is prepared by mechanically separating non-combustibles and subsequently shredding the remaining organic portion into uniform particle sizes. This refuse derived fuel (RDF) can be further treated chemically to produce a fine powder or pressed into briquettes or pellets. The RDF is then either mixed with the sludge and fed together into the top of the incinerator, or fed separately into one of the lower hearths. Although at least three units of this type operate in Europe, it has not been fully demonstrated in the U.S. Some testing has been done at a demonstration facility in Contra Costa County, California. Based on limited operating data, the major problem with this design is controlling the rate of combustion in the incinerator. Localized overheating caused by periodic intense heat release from the RDF can lead to structural failures in the rabble shaft castings. To compensate for the higher heat release rate associated with co-burning RDF, a greater volume of cooling air is required. If air flow rates are higher than designed, the movement of the sludge and refuse through the hearths could be impeded. Besides installation of all the facilities required to produce the RDF, substantial modifications to the incinerator itself are necessary in order to co-incinerate. The major benefit a ssociated with this type of system is the reduction in fue I costs for sludge incineration. Fuel costs represent the largest share of the total annualized costs of operating MHF incinerators. Combustion of RDF in a Fluidized Bed Sludge Incinerator T his approach is analogous to that described above, except that co-incineration would take place in a fluidized bed sewage sludge incinerator. The RDF can either be introduced into the furnace as dry pel lets, fluff, or powder. The fluidized bed incinerator is comprised of a vertical, cylindrical, heat resistant, lined vessel with a perforated grid in.the lower section which suports a sand bed. A reaction vessel contains 89 the sand f luid bed, there is a space above the bed called a freeboard, and a gas distribution plate above the freeboard space. Sludge is fed into the fluidized bed region with some combustion of the sludge occurring in the freeboard space. As sludge burns out primarily in the bed, the finer ash particles are then swept from the bed. Compared to co-incineration in a multiple-hearth incinerator, use of a fluidized bed furnace offers a number of advantages. Foremost is that combustion is more easily controlled in a fluid bed, and furnace operation is less vulnerable to changes in the sludge feed rate or moisture content, due to both the excellent mixing characteristics and longer residence time typical of these incinerators. As in the case of multiple-hearth furnaces, however, t he incinerator must be modif ied significantly to burn RDF. Besides the addit-ion of a feeding mechanism, a system is needed to separate inert RDF materials that build up in the sand bed. The interior of the furnace shell must also be protected from the corrosive condensation of hydrochloric acid (HCl) and hydrofluoric acid (HF) evolving from combustion of plastic materials. Co-incineration Projects in the U.S. All the available techniques for combined incineration of sewage sludge and municipal refuse have been at one time or another tried in the U.S. in either commercial or pilot-scale plants. No single approach has emerged as a definitively "best" technique, although burning pre-dried sludge in a conventional refuse incinerator has been attempted most often. A comprehensive list of former, present, and planned co-incineration projects in the U.S. is provided in Table 28. Only one facility, at Stamford, Connecticut, is currently co-incinerating on a regular commercial basis. The facility in Glen Cove, New York is operating. Of the 32 facilities listed, 18 units that formerly were co-incinerating have been shut down or abandoned completely and four facilities have reverted to single purpose incineration. Of the six major co-incineration projects considered during the mid-1970s, only the Glen Cove facility is currently operative. In quite a few cases, plants that have shut down have done so for technical reasons. Operating problems have plagued some of the new, as well as the older, co-incineration facilities. The Ansonia, Connecticut, Duluth, Minnesota and Holyoke, Massachusetts plants have each experienced equipment failures. Even the Stamford plant has been unable to co-incinerate on a con tinuous basis since the facility began operating in 1975. New pyrolysis reactors have yet to demonstrate an adequate level of operating reliability when processing refuse alone, and the feasibility of co-incinerating in these units is still undetermined. Economic and institutional Considerations for Co-Incineration From the standpoint of annualized operating costs, co-incinerating sludge and refuse appears to be an attractive waste management approach in sit uations where landfilling or other disposal options are unavailable. In contrast, there are numerous institutional barriers to co-incineration that can negate the economic incentives for co-disposal. 90 TABLE 28 CO-INCINERATION FACILITIES IN THE UNITED STATES location Capacity Design Parameters operating History Current Status Holyoke. Massachusetts 226 tpd KRF Twin Fixed-Grate Began operating In Shut down In 1976 10 tpd sludge MRF Incinerators 1966 Lansing. Michigan DNA MIIF Sludge Incinerator Attempted to Burns sludge only Coincinerate Trenton. Michigan ONA Hass-Burning MRF Began operations in Shut down Incinerator 1964. By 1975. sludge Sludge Flash-Evaporated dried and landfilled Duluth, Minnesota 160 tpd ROF FBI sludge Incinerator Began operating In 1979 Burns sludge only. 70 tpd sludge Sludge Pre-dried Shut down due to No plans to resume explosion coincineration Minneapolis/St. Paul. 400 tpd MRF Rotary kiln In Planned for 1980 Plans Abandoned Minnesota 60 tpd sludge Pyrolysis Mode Start-up In 1976 Vicksburg. Mississippi OKA Rotary kiln DNA Abandoned Glouchester City. New Jersey DNA Rotary kiln DNA Abandoned Tenafly, New Jersey DNA Kass-burntag KRF DNA Shut-down Incinerator Sludge Flash-Evaporated Glen Cove, New York 250 tpd MRF Twin Reciprocating-Grate. Began operating In 1983 In Start-up 25 tpd sludge MRF Incinerators Sludge Dewatered Newburg. New York DNA Mass-burning HRF Began operating In 1970. 4bandoned Incinerators Redesigned In 1974. Sludge Flash-Evaporated Orchard Park, New York DNA Torrax Air-Blown DNA DNA Shaft furnace (Carborundum Test Facility) Vata rut f'V6j!aj:je CO-INCINERATION FACILITIES IN THE UNITED STATES totation Capacity Design ParAmeters operating History Current Status Waterville. New Vork DNA Mass-burning MRF Began operating In 1940 Abandoned Incinerator Sludge flash-tvaporated Franklin. Ohio 150 tpd ROF FBI Incinerator Began operating In 1971 Sbut-down In 1979 30 tpd sludge MRF vet-Pulped Bloomburg. Pennsylvania D" Mass-burning MRF Began operating In 1953 Abandoned Incinerator Sludge flasit-Evaporated Harrisburg. Pennsylvania 120 tpd MRF Twin Materwall HAF Expected start-up In 60 tpd sludge Incinerators 1979 Coinclaeration Sludge Dewatered Hershey. Pennsylvania am Mass-burning MRIF Operated from 1963 Kbandoned Incinerators to 1912 Sludge Dewatered Whitemarsh. Pennsylvania IS tpd MRF Has%-burning MRF DNA Abandoned 6tp4 sludge Incinerator Sludge Dewatered Georgetown, South Carolina DNA Rotary kilo DNA Abandoned "his, Tennessee 7400 tpd HRF MRF Conversion to RDF reas6bility Stuilles Plans Abandoned 1225 tpd sludge 1411' Incinerator In Completed Pyrolysis,Mode Snuth Charleston, West Virginia 200 tpd 14RF Puro; Oxygen-filown Began testing In 1975 Refuse only Shaf Pyrolysis furnace (Union Carbide) Kedashum. Wisconsin 75 tp4 KRF Kass-burning MRF Began operating 141''1954 4bandoned Incinerator Peenah-Menash, Wisconsin 150 tpd MRF Twin Traveling-Grate Begav.operbtiug 10 1958 Shut-down In 1959 IIHA Data Not Available TABLE 28 CO-INCINERATION FACILITIES IN TRE UNITED STATES Location Capacity Design Parameters operating History Current Status Contra Cost& County. 1200 tpd MRF HIF sludge Planned; Feasability Abandoned Plans California 160 tpd RDF Incinerator/Pyrolysis Study completed For Colacineration 95 tpd sludge Mode San Diego. California DNA Flash Pyrolysis DNA DNA. (Occidental Test Facilty) Ansonia. Connecticut 40 tpd KRF Hass burning MRf Ceased operations burns Refuse Only. 13 tpd sludge Incinerator In 1977 due to fire. Sludge Is dribd and Sludge Pre-dried landfilled Stamford, Connecticut 360 tpd KRF Twin Rocking-Grate Began operations in Still coincinerating to tpd sludge. MRF Incinerators 1975. Lj Waterbury, Connecticut 300 tpd MRF Twin Hass-burning MRF Began operations In 1951. Shut down In 1978, Incinerators; Sludge Ceased burning sludge F)ash-Evaporated 1975. West Albany. Indiana 160 tpd MRF Twin Traveltng-Grate Began operatIngAn 1959 Abandoned MRF Incinerators Sludge Flash-Evaporated Louisville, Kentucky 850 tpd MPF Reciprocating-Grate Began operating In 1959 Burns 14RF only MRF Incinerators Sludge Flash-Evaporated Auburn, Maine 150 tpd MRF Consumat Modular Groundbreaking Schedule,l plans Abandoned to tpd sludge MRF Incinerators for 1979 Sludge Pre-dried Baltimore. Maryland DNA Landgard Rotary Kiln DNA DNA (Monsanto Test facility) Frederick, Maryland DNA "ass-Burning MRF CoincIneratIon Abandoned Incinerator Unsuccessful DNA - Data not Available SOURCE: UShPA Spwor)d Rpir4ew of Rfandwrd-,- nf Pn-rf ------- Costs of Co-incineration The most comprehensive asssessment of the costs of co-incineration was conducted in 1976 by Roy F. Weston, Inc. for the USEPA. In this study, the costs for separate incineration of sludge and refuse were compared to the costs of four combined incineration systems. Costs for non-thermal dis posal options are also used for comparison. The co-incineration design considered include a multiple-hearth unit burning RDF, a Torrax pyr olysis shaft furnace, and two systems based on the use of a conventional refuse incinerator with pre-drying (either direct or indirect ) of the sludge. The principal conclusion of this analysis was that for all combustion technologies considered, co-incineration had the lowest annualized costs. Al-l four combined incineration systems were shown to be less costly to build and operate when compared to the costs for incinerating these wastes separately. Burning dried sludge in a mass-burning refuse incinerator was the lowest cost option. However, all types of incineration involved higher .costs than land or ocean disposal. The capital costs of constructing a co-incineration facility could, nonetheless, be prohibitive to many municipalities. Forexample, the capital cost of a multiple-hearth furnace burning refuse-derived fuel was estimated to be nearly four times higher than the same furnace burning fuel oil. Institutional Factors Affecting Co-incineration Institutional issues embody a number of complex legal, organizational, and administrative factors which relate to waste water and solid waste management. These factors often serve to discourage combined disposal of municipal sewage sludge and refuse. Water- and solid waste-related management programs have evolved along different paths. While water quality programs were initiated through pub lic action, solid waste handling and disposal has remained predominantly a private concern. Water quality management programs are highly centralized within public bodies. In contrast, solid waste management is much less centralized, with authority vested in various groups, some private and some public. Moreover, different aspects of solid waste removal, collection, transport, processing, storage, and disposal can be controlled by different entities. These organizational differences alone are obstacles to integrating municipal waste management and planning. From the perspective of those responsible for municipal refuse management, there is no real incentive to engage in a co-incineration project, especially when refuse disposal is carried,out by private companies. Siting a co-disposal facility creates numerous problems since the criteria by which potential sites are judged are not mutual. The location of a sewage treatment plant is determined by hydrological boundaries. Collection and disposal of municipal refuse is organized according to municipal boundaries. Rarely do these locational parameters overlap. 94 Municipal Waste Characteristics Municipal solid waste consists of residential, commercial, and other wastes, excluding hazardous wastes. The high organic content (paper, plastics, food, textiles, etc.) of this waste is desirable for incin eration in resource recovery plants as it is this organic material which is combustible. It is the same part of the waste stream that is least desirable for landfilling because it can produce leachate (contaminated wastewater from a landfill) and methane gas. Metals and glass are non-combustible and make up the largest fraction of the ash residue after bur ning. Iron is typically the largest portion of the metal. constituent by weight. Prospects for Growth of Co-incineration Little growth in co-incineration is likely to occur over the next five years because co-incineration has yet to be widely demonstrated as a reliable disposa:1 technique. The failure of the vast majority of the systems put into operation in the past has clearly impeded the widespread acceptance of the technology. However, plants are currently operating in Stamford, Connecticut; Glen Cove, New York; and Harrisburg, Pennsylvania. Countering these technical uncertainties, however, are the economic inc entives to co-incinerate refuse and sewage sludge. With the rise in the cost of fossil fuel over the past five years, these incentives have become more attractive. Also, the costs of incineration should approach the costs o f land disposal as a result of'stricter regulations', increased enforcement, and declining availability of land disposal.sites. Residual waste streams associated with resource recovery activities include processibles, no n-processible bottom fly ash residues, as well as various types of wastewaters. Non-processible materials contained.in municipal solid waste ordinarily are not accepted at a resource recovery facility. These materials. consist largely of construction and demolition debris and bulky white goods such as appliances. Characteristics of Ash Residue When solid waste and sludge are burned, an ash residue results which requires disposal. The total amount of ash remaining from the combustion process is generally equal to about 10 to 15 percent of the original volume of processible municipal solid waste, or about 20 to 25 percent of the original weight. The ash residue produced as a result of the combustion process consists of bottom ash, which collects at the bottom of the furnace chamber, and fly ash, which is the fine matter extracted from the flue gas. Particulate matter can be removed using a variety of air cleaning equipment including electrostatic precipitators, bag houses, or other devices. In most cases, 95 the bottom and f ly ash is combined and quenched with water to cool the material and control dust. After quenching, ash will typically contain approximately 20 percent water. This amount of moisture prevents dust, but leaves no free liquid in the material. The compos'ition of the ash depends on the composition of the waste burned, and will vary according to the technology used to process the waste. Mass burn technology, which is being proposed most frequently at this time, usually burns over 95 percent of organic matter. A typical chemical c omposition of ash residue from a mass burn facility is listed in Table 29. The largest constituent by weight is glass which is almost completely non-reactive (inert). Iron and aluminum combined with oxygen burn during the combustion process and comprise about 15 percent of the residue by weight. Other materials, such as calcium,,magnesium and zinc form oxides which are present in smaller quantities. The solubility of some of these residue components depends on whether they are basic or ac idic. Acidity tends to increase solubility, and promotes leaching. The ac idity of ash can be reduced by adding lime or other basic material to the ash, similar to the way a gardener might add lime to a lawn to reduce the acid nature of the soil. Ash residue will contain some heavy metals such as lead, zinc, or cadmium so toxicity must be considered. Organic compounds, including those having toxic potential, such as dioxins or furans, may also be contained in the res idue in small quantities, although the majority of these compounds would have been destroyed in the combustion process. Following EPA procedures-, the toxicity of ash residue generated at various municipal incinerators, co-disposal facilities and resource recovery fac ilities is assessed using the extraction procedure (EP test) designed to identify some toxics that could leach from the given waste material. If the test identifies any metal or regulated organic chemical at a concentration greater than 100 times the National Interim Drinking Water Standards, it is defined as toxic and hazardous and requires special handling and disposal under the Federal Resource Conservation and Recovery Act (RCRA). Mos t toxic organic compounds will be destroyed if the combustion process is properly designed and operated to maintain the elevated temperatures required and if adequate burning time (residence time) in the combustion chamber is ensured. Tests have confirmed that dioxin, one organic of concern, has been found in ash produced by the operating resource recovery fac ility in Glen.Cove, but this type of test data on ash residue is limited and no long term studies exist. Recent EP toxicity tests performed on ash residue from plants in Westchester and Cattaraugus counties in New York, and Pinellas County, Florida have all indicated that the combined ash passes the EP toxicity standards and all have been classified as non-hazardous. Table 30 presents the results of EP toxicity tests performed by the U.S. Environmental Protection Agency on ash residues from a mass burn facility, as well as data from Westchester and Cattaraugus counties and Baltimore, Maryland facilities. Actual concentrations are compared with the maximum allowable concentrations. 96 TABLE 29 TYPICAL CHEMICAL ANALYSIS OF CARBON AND MOISTURE-FREE INCINERATOR RESIDUE Material Molecular Formula percent Silicon dioxide (silica, Sio 2 .59.8 primarily from glass) Aluminum oxide (alumina) Al 203 9.8 Iron oxide Fe 203 4.0 Titanium dioxide TiO 2 1.0 Calcium oxide (lime) CaO 11.9 Magnesium oxide MgOi 3.0 Zinc oxide ZnO 0.4 Lead oxide PbO 0.11 Copper oxide Cuo 0.1 Manganese oxide Mno 0.3 Sodium oxide Na 20 6.1 Po tassium oxide K2 0 0.5 Sulfur trioxide S03 0.9 Phosphorus pentoxide P, 205 0.5 Other 1.6 Total 100.0 Source: Collins, Robert J., uPromising Applications for Municipal Incinerator Residues,4 Proceedings of the Sixth Mineral -Waste Utilization Symposium, US Bureau of Mines, IIT Institute, Chicago. May 2-3, 1978. 97 TABLE 30 EP TOXICITY TEST RESULTS OBSERVED CONCENTRATIONS Contaminant Maximum Large Mass Permitted Burning Plant Concentrations Composited Fly (maximum allowable Ash and Bottom concentrations Ash as Landfilled in EP test (Ppm)) (ppm) (1) (2) (3) (4) Arsenic 5.0 <0.01 0.31 0.0025 0.01 Barium 100.0 0.16 0.40 0.184 0.54 Cadmium 1.0 0.99 <0.005 0.251 0.20 Chromium 5.0 0.02 <0.05 0.039 <0.001 Lead 5.0 3.68 <0.01 0.337 1.53 Mercury 0.2 <0.001 <0.10 O.U001 <0.001 Selenium 1.0 <0.012 <0.062 0.0025 <0.01 Silver 5.0 <0.001 <0.05 0.001 <0.005 (1) Cattaragus County, NY, NYSDEC, 1984 (2) Westchester County, NY, RESCO Ash Residues: City of New York, Department of Sanitation, Final Environmental Impact Statement, Proposed Resource Recovery Facility at the Brooklyn Navy Yard, 1985. (3) Steam-generating municipal solid waste incinerator, capacity greater than 1000 tpd. No industrial waste burned. Adapted from Waste Age, February 1981. (4) Baltimore RESCO Ash Residues: City of New York, Department of Sanitation, Final Environmental Impact Statement, Proposed Resource Recovery Facility at the Brooklyn Navy Yard, 1985. SOURCE: NYSDE.C, City of New York,"Waste Age"Department of Sanitation ppm parts per million 98 Pyrolysis and Starved Air Combustion These two proces.ses refer to the thermal decomposition of sludge in a zero air or low air concentration atmosphere. They do not result in complete combustion of the sludge. Like incineration, these processes result in a drastically reduced volume of wastes which are sterilized. However, unlike incineration, the incomplete combustion process produces products consisting of combustible materials. As such, they must be handled subsequent to the pyrolysis process. Figure 10 presents a schematic of a pyrolysis plant. With the exception of fluidized-bed furnaces, all the incineration techniques described previously can be operated in a starved air or pyrolysis mode. Thus, pyrolysis represents not so much a distinct technology type as it does a general operating technique, applicable to a number of alternative technologies. Four incinerators specifically designed to operate as pyrolytic reactors are presently under development. T h e s eRi-ncinerators inclu le the Purox R (Union Carbide), Torrax (Carborundum), Landard (Monianto), and R the Flash Pyrolysis (Occidental) systems. Both the Purox and Torrax R processes are based on a vertical shaft reactor design; the Landgard system uses a rotary kiln. , All these technologies are being developed primarily for municipal ref use. Each, however, has also been considered foi co-incineration. Some testing has been done for this purpose. In a conventional refuse incinerator, combustion under starved air conditions is the most common operating technique. Generally, however, combustion air is added at only slightly less than theoretical rates. The exhaust gases from the furnace are then combusted in an afterburner. The smaller, modular refuse incinerators that have been widely used since the early 1970s are almost always designed to operate under starved air conditions. Operating a multiple hearth sewage sludge incinerator in a pyrolysis mode is a technique developed specifically for co-incinerating refuse. As described earlier, controlling the rate of combustion is the major problem with co-incinerating in these furnaces. These problems are effectively overcome by operating the furnace as a pyrolysis reactor. - During a series of comprehensive tests conducted on an MHF at the Contra Costa County, Cal ifornia demonstration project, operating the furnace in a pyrolysis mode emerged as the preferred means of co-burning refuse with sewage sludge. The major manufacturers of multiple hearth furnaces also recommend that the uni t be operated in a pyrolysis mode when co-incinerating municipal refuse. Other benefits associated with this approach are an increased furnace capacity and the capability for pyrolysis to become autogenous with sludges having a low solids content. 0 99 RAW REFUSE LANDFILL REFUSE REFUSE PROCESSING GASIFIER OF RESIDUE FEEDER REFUSE UPPER STACK PLUG COMBUSTIBLE REGENERATIVE GAS "EAT 4 AIR DRYING EXCHANGERS ZONE COMBUSTION AIR FINAL SOLIDS COMBUSTION PYROLYSIS -BASES SECONDARY WASTE ZONE HEAT COMBUSTER BOILER COMBUSTION AIR PRIMARY COMBUSTION AND ELECTROSTATIC GAS MELTING ZONE SL AD SECONDARY EXHAUST 1 DROP OfF COMBUSTION PRECIPITATOR COOLER GASIFIER AND CHAMBER UENCH CARBORUNDUM'S TORRAX PYROLYSIS FACILITY G EN " E E) XCH4 [@E _t@A SNE "EAT 80; ILER SOURCE: EPA Process Deisgn Manual Sludge Treatment and Disposal, September 1979, P. 11-87 The major disadvantage of all types of pyrolysis is the greatly increased complexity of the system. The furnaces must be well -sealed against air infiltration, the interior linings must be highly corrosion resistant, and additional controls and instrumentation are required. Moreover, to be economically viable these systems must be able to recover and use the energy content of the exhaust gases. Heat recovery systems add to the overall complexity and capital costs of the facility. Finally, a greater volume of re@idual ash and char is produced when wastes are processed by pyrolysis than by incineration. Pyrolysis offers three distinct advantages over incineration: 1. The lower air requirements result in less exhaust gases. Exhaust gas cleaning equipment is less expensive, therefore, as it handles a considerably smaller volume of gas 2. The pyrolytic gases, oils and chars produced in the combustion process present more usable byproducts than incineration 3. Less energy is used. Depending on the heat generated in the pyrolysis process, three distinct modes of operation result' low temperature char, high temperature char and char-burned. The char-burned mode is much like incineration in that a true ash is produced. This mode also produces the most recoverable heat. The low temperature char process only pyrolyzes the combustible material, leaving a charcoal-like residue which is high in ash content. High temperature char produces a smiliar charcoal-likematerial. An analysis of the various chars is presented in Table 31. Unfortunately, pyrolysis has not been the saviour of sludge disposal that was projected by many manufacturers. Although theoretically pyrolysis offers many advantages, these systems have not been reliably demonstrated. Sludge Characteristics and Thermal Reduction The most important sludge characteristics for maintaining a thermal process are the heating value, moisture content and ash content of the sludge. The heating value of various residuals collected during sewage treatment is presented in Table 32. Raw sewage solids generally contain about 10,000 Btu/Ib. of volatile (combustible) solids. Greases, however, have a considerably greater heating value, generally between 16,000 and 17,000 Btu/lb. A comparison of the heat value of various sewage treatment residuals with other fuels is presented in Table 33. Representative chemical analyses of refuse and sewage sludge samples are shown in Table 34. 101 TABLE 31 PROXIMATE ANALYSIS OF PYROLYSIS CHAR Proximate Analysis of Pyrolysis Char at Indicated Temperature (OF.) Pennsylvania 900 1200 1500 1700 Anthracite Coal Volatile matter, 21.81 15.05 8.13 8.30 7.66 A Fixed carbon, 70.48 70.67 79.05 71.23 82.02 Ash, .7.71 14.28 12.82 14.47 10.32 Btu per lb 12,120 12,280 11,540 11,400 13,880 SOURCE: Los Angeles County/Orange County Sludge Processing and Disposal, April 1977, p. 7-10 102 TABLE 32 HENTING VALUE OF TYPICAL RESIDUALS COLLECTED DURING SFKAGE TREATMENT MATERIAL C014BUSTIBLES M STU/LB OF COMBUSTIBLES GREASE AND SCUM 88.5 16,750 RAW SEWAGE SOLIDS 74.0 .10,285 FINE SCREENINGS 86.4 81990 GROUND GARBAGE 84.8 8,245 DIGESTED SLUDGE 59.6 5,290 GRIT 33..2 4,000 SOURCE: Los Angeles County/orange County Sludge Processing and Disposal, April 1977, p. 7-15 103 TABLE 33 COMPARATIVE HEATING VALUES OF PERTINENT FUELS HEATING VALUE RATIO OF FUEL VALUES FUEL (BTU/LB) TO VALUE FOR NO. 2 OIL NO. 2 OIL 19,600 1.00 NO. 6 OIL 17,500 0.89 NATURAL GAS 22,800 1.16 BITUMINOUS COAL 0.69 %DOD (AIR DRIED) 5,500 0.28 GREASE AND SCUM 16,700 0.85 SLUDGE (DIZ@ VOLATILES) 10,000 0.52 DIGESTER SLUDGE 5,300 0.27 DIGESTER GAS 15,400 0.79 MUNICIPAL REFUSE 4,900 0.25 (20% MOISTURE) SOURCE: Los Angeles County/orange County Sludge Processing and Disposal, April 1977, p. 7-17 104 TABLE 34 Representative Chemical Analyses (Weight %) and Heat Contents (Btu/lb) of Dry Refuse and Sewage Sludge Sanple,- Digested Constituent Refuse Raw Sewace Sewage Carbon 33.11 37.51 24.04 Hydrogen 4.47 5.54 3.98 Oxygen 25.36 22.56 12.03 Nitr ooen 0.60 1.97 2.65 Chlorine 0.41 0.33 0.17 Sulfur 0.14 0.37 0.75 Metal 11.64 - - Glass, ceramics, stone 16.23 - - Volat-iles @ 110* C - 3.66 3.01 Ash 8.04 28.06 53.37 100.00 100.00 100.00 Higher Heating Value 5,902 7,040 4,64-0 SOURCE: Los Angeles County/Orange County Sludge Processing and Disposal, April 1977, p. 7-16 10 Calculations can be made regarding recoverable heat and the need for auxiliary fuel during combustion based on average heat values for sewage sludges and typical operating conditions in combustion reactors. Figure 11 relates natural gas consumption to the moisture content and volatile solids fraction of the sludge. Recoverable heat from the combustion of sewage sludge is presented in Figure 12, while the amount of refuse required for combination with raw or digested sludge at various total solids levels to achieve self-sustaining combustion is shown in Figure 13. Assumptions as to the amount of heat released by the combustion of sludge solids and -refuse, used in the development of Figures 12 and 13, are presented in Table 35. It should be emphasized that Figures 11 through 13 give only approximate values since average fuel values are assumed. More importantly, average combustion processes are assumed. Figure 14 presents a thermodynamic approach to evaluating thermal reduction systems. The values presented in the previously presented tables and figures can be used to project energy production, amount of auxiliary fuels needed, and basically to compare various thermal reduction systems. Research information from the manufacturers of various thermal reduction systems would-be invaluable in performing these analyses. The general information in this section is presented to make the reader aware of the value of sludge'as a fuel as compared to other materials and to point out the type of analyses which are performed to evaluate various combustion systems. Advantages and Disadvantages of Thermal Reduction Some of the advantages to using thermal reduction are: 0 It provides maximum volume reduction of sludge 0 It destroys or reduces many toxic sludge constitutents 0 It can be used to produce energy, thereby reducing overall costs 0 It does not require a large commitment of land resources. Disadvantages of its use are: � They are costly to build and operate � Exhaust gases contain considerable particulates and can be odorous � Many systems have proven unreliable in the past � Highly skilled operators are required � Large amounts of fuel are sometimes needed to sustain these processes. Given both the advantages and disadvantages, heat reduction processes are only economical when large amounts of sludge are to be handled. 106 FIGURE 11 IAM Uj LLJ Sludge heat content-10,000 Btu/lb LL- - volati le solids 1,400 LLI ?.b z 0 1,200 0'0 0 LL- 1,000 SO 0 Z 800-- 0 CL 600-- cf) z o 400-- Cl) < 200-- < 0 z 17 18 19 20 21 22 23 24 25 SOLIDS CONTENT OF FEED, PERCENT The effects of sludge moisture and volatile solids content on gas consumption SOURCE: LosAugeles County/Orange County Sludge Processing and Disposal, April 1977, P. 7-19 107 FIGURE 12 100 so- 060-- Cn 40-- 20 0 2000 4000 6000 sboo 10000 Btu/Ib Recoverable heat from combustion of sewage sludge SOURCE: Los Angeles County/Orange County Sludge Processing and Disposal, April 1977, A:@ p. 7-20 108 0 REFUSE (AS RECEIVED). BASED ON TOTAL WET WEIGHT m 0 0 0- k4 m ch Fh En co m > crQ (j) G) v m -4 m rn 0 rt Fl- 0 0 ct Z (n 0 00 xlz@ -j r- , CA rL m > 0 oQ m m 'o .0 0 rn 0 -A 0 U) m U) Eo ch 0 c 3: Z 1?0 0 Q tv do CIQ rn 0 M 0 03 8 130 rt 0 THERMODYNAMIC SYSTEM BOUNDARY ABOUT A TYPICAL THERMAL PROCESSING SYSTEM Flue Gas THERMODYNAMIC SYSTEM BOUNDARY Material Entering Material Leaving TYPICAL 'THE RMAJ- Thermodynamic Thermodynamic PROCESSING SYSTEM System Boundary System Boundary Sludge PYROLYSIS Heat Entering Heat, Leaving Combustion Air 0. OR Thermodynamic Thermodynamic INCINERATION System Boundary System Boundary Auxiliary Fuel C-1 Ash SOURCE: Los Angeles County/orange County Sludge Processing and Disposal, April 1977 TABLE 35 HEAT RELEASED ONZ COMBUSTION OF REFUSE AND SEWAGE SLUDGE (HIGHER HEATING VALUE,,BTQ/LB) MATERIAL RANGE AVERAGE VALU E USED Raw sludge (primary or 6500-9500 8400 activated dry solids) Digested sludge (from anaerobic- 2500-5500 4200 treatment, dry solids) Chemical sludge (e.g. lime from nil nil tertiary treatment Refuse (as received,.25% average 3700-4700 4200 moisture content) Refuse (air-classified 5000-6000 5500 combustibles) Evaporation of 1 lb. of water -(1800-2500) -2100 in a furnace setting. SOURCE: Los Angeles County/Orange County Sludge Processing and Disposal, April 1977, p. 7-18 Heat Treatment Sludge is heat dried when a thermal reduction process is to be used fol lowing the drying step or if a fertilizer or soil conditioner product is desired. Each of the processes described here will produce a dried sludge which is nearly pathogen free, contains only five to ten percent moisture, and is reduced in volume by approximately 25 percent. If the production of a commercial grade fertilizer is desired, it may be necessary to include a pelletizing or granulating step due to the production of dust and fine sludge particles. In addition, exhaust gases from the heat drying process must be deodorized and the suspended particles removed by scrubbing. Heat drying is expensive as far as both capital and operation'and maintenance costs are concerned. The drying units use a considerable amount of fuel and require experienced and knowledgeable operators. Because fuel costs are so high with this process, it is always cost effective to remove as much water from the sludge as possible prior to the heat drying step. Theoretically, it takes approximately 1,000 BTUs to convert one pound of water to a vapor at atmospheric pressure. As is illustrated in Figure 15, the amount of water in a given sludge varies considerably in the five to 25 percent solids range. During heat treatment, sludge is heated to temperatures which are too low to destroy organics but high enough to evaporate water. No combustion takes place during heat treatment. Sludge goes through three stages during heat drying: initial drying, steady state drying and final drying. During the initial stage, little drying occurs, as the sludge is just coming up to process temperature. At the steady state stage, water is evaporated at a rapid rate as the tempeature reaches about 320 0C. As quickly as water travels to the sludge particle surface, which at this point is saturated, it is lost in the moist air. in the final drying stages, sludge concentrations approach 95 percent. At this point, the sludge particles are not saturated and little additional drying takes place as-most of the water has been removed. A number of methods are used to dry dewatered sludge: flash dryers, spray dryers, rotary dryers, indirect heat dryers, toroidal dryers, oil immersion dehydration and solvent.extraction. Flash Dryers Flash dryin g blends dewatered sludge with hot dried sludge, then mixes the blended sludge with hot furnace gases. The mixture is introduced into a mechanically agitated cage mill where drying occurs in a matter of seconds. The hot gases, propelled at velocities up to 100 feet/second, convey the solids through the system. Dried sludge is then separated from the hot gases in a cyclone (see Figure 16). Exhaust gases from the cyclone must be deodorized, then scrubbed. This creates a liquid sidestream which must be treated. 112 .0 0 LBS. WATER PER I LB. DRY SOLIDS kD m 0 h) (D 0 F4 T, di @j fu ru 4 m (n 0 lu 0 CL 0 C: :3 :3 o rt 0 0 A) H :3 rr 03 M :j 0 (IQ m m rlr 0 cl ::r 0 m a rn F@ rt (D M x Lo rl 14 r) fu m qj rl ti z (10 0 m r? ou 0 M 0 Pi CL 0 Cl) 0 Ul oQ r? r) (D U) 0 tv 00 0 0 (n Lo 0 FIGURE 16 EXHAUST GAS RELIEF -VENT -------- CYCLONE STACK AUTOMATIC DAMPERS VAPOR FAN INDUCED DRAFT FAN WL EXPANSION SCRUBBER JOINT EXPANSION---.-,.. EXPANSION JOINT DOUBLE MANUAL LAPVALVE JOINT REMOTE DRY DAMPERS DIVIDE1 COMBUSTION AIR PREHEATER INLET DRY PRODUCT AIR CONVEYOR WETSLUDGE DEODORIZING CONVEYOR PREHEATER MIXER FURNACE DISCHARGE SPOUT BURNERS AUTOMATIC DAMPERS COM13USTI N AIR 0AN CAGrz MILL HOT GAS DUCT M81. @@C OIR P R FLASH DRYER SYSTEM (COURTESY OF C.E. RAYMOND) SOURCE: Los Angeles County/Orange County Sludge Processing and Disposal, April 1977, p. 6-4 114 Spray Dryers Spray dryers are similar to flash dryers in that drying is rapid. Liquid sludge is atomized and sprayed into the top of a vertical tower. The tower is filled with hot gases and the sludge dries almost instantaneously. The sludge/gas mixture is then separated in a cyclone separator. Rotary Dryers A rotary dryer consists of a horizontal revolving cyclinder into which sludge' is fed. Hot gases flow through the drum or cylinder at a velocity of approximately four to 12 feet/second. The sludge is moved by flights proj ecting from the interior walls of the drum through the drum, and discharged into a cyclone for separation. Sludge is retained in the drum for 30 to 60 minutes before being discharged. As with the flash dryer, incoming sludge is mixed with some dried sludge to ease handling of the inlet sludge. A schematic of the rotary process is shown in Figure 17, along with some common options for deodorizing and scrubbing the gas exhaust stream. Indirect Heat Dryers As is implied by the name, in this process the sludge to be'heat dried does not actually come into contact with the hot-gases. . Indirect heat dryers are normally of a rotary type and can be operated in a batch or continuous mode. Figure 18 illustrates a typical indirect heat dryer. Sludge is fed into one end of the unit and is pulled through it by interior screw-type flights. Hot gases are passed through the jacketed exterior of the dryer, transferring their heat to the sludge. Water vapor driven from the sludge is collected, condensed and then directed to one of the deodorizing schemes outlined in Figure 19. Toroidal Dryer The toroidal dryer uses the jet mill principle, has no moving parts and dries and classifies solids simultaneously. A schematic of the process is outlined in Figure 20. As in most dryers, inlet sludge is blended with he.a t treated sludge and is fed into a doughnut-shaped reactor vessel, where it comes into contact with heated, fan-blown air. At the vessel outlet, fine, dried particles exit with the hot, moist air and are discharged to a cyclone. Wet, undried sludge remains inside the reactor until finally dried to a point where it can exit to the cyclone. Exhaust gases must be deodorized and scrubbed. 115 Direct Discharge to Atmosphere SCHEMATIC OF ROTARY DRIER Chemical 0- Atmosphere Scrubber Not Exhaust 6000- Gases Rotary Gases, Heat WOOF Burner Air-o- Furnace - _W C yclone 12000- Drier 3.0001`@"_ Exchanger 1500OF 1400OF t Fuel Blended Sludge Dried Scrubber up Atmosphere Sludge 180OF-200OF Blander L_.w Burner m, Scrubber -to. Atmosphere 1500OF Disposal Fuel- Food Sludge v ALTERNATIVES AVAILABLE FOR EXHAUST GAS DEODORIZATION AND PARTICULATE REMOVAL SOURCE: Los Angeles County/OrAnge County Sludge Processing and Disposal, April 1977, p. 6-3 He al _fE xchai \Y/ db 4P FIGURE 18 INLET BREAKER BARS JACKETED VESSEL fl ROTARY JOINT AGITATOR DISCHARGE JACKETED HOLLOW-FLIGHT INDIRECT DRYER SOURCE: EPA, Process Design Manual Sludge Treatment and Disposal, September, 1979, p. 10-23 I Z' 117 Direct Discharge SCHEMATIC OF ROTARY DRIER to Atmosphere Chemical 1P Atmosphere Scrubber flot Exhaust 6000- Gases Rotary Gases Heat WOOF Burner Air Furnace - 0 C yclone 10 --v 12000- Drier 300OF Exchanger 1500OF 1400OF t Fuel Fuel 00 Blended Sludge Dried Scrubber 0- Atmosphere Sludge 180OF - 200OF - Blander L--* Burner Scrubber --e. Atmosphere 1500OF Disposal Fuel Fj Food Sludge --vl ALTERNATIVES AVAILABLE FOR EXHAUST GAS DEODORIZATION AND PARTICULATE REMOVAL SOURCE: Los Angeles County/Orange County Sludge Processing and Disposal, April 1977, p. 6-3 0 WET SLUDGE FROM WASTEWATER EXHAUST GASES PLANT SEE FIGURE 14, FOR OPTIONS WET SLUDGE STORAGE CYCLONE BLOWER AIR DISPOSAL INLET AIR HEATER TOROIDAL DRYER F4 SLUDGE DRYING SYSTEM USING THE JET MILL PRINCJPLE - TOROIDAL DRYER SOURCE: Los Angeles County/Orange County Sludge Processing and Disposal, April 1977, p. 6-3 Oil Immersion (Carver-Greenfield Process) In the Carver-Greenf ield system, water is extracted from sludge by evaporation using a multi-effect evaporator. A system flow diagram of the process is shown in Figure 21. Sludge to be processed is first thickened or dewatered as much as possible and is then mixed with an oil in a fluidizing tank at a ratio of one part dry solids to five to 10 parts oil. The use of oil improves heat transfer and helps prevent scaling on heat transfer surfaces. The sludge/oil slurry is pumped to the multi-effect evaporator where water is vaporized. Steam provides the heat necessary for the evaporation. The remaining water-free solids/oil mixture is normally centrifuged to separate the oil and solids. The oil is recycled and reused, while the dried sludge is discharged for further processing or disposal. The Carver-Greenf ield system uses the falling film evaporation process. Water to be evaporated is removed from the sludge as the oil sludge mixture rolls down the evaporator tubes (see Figure 22). When the hot oil sludge slurry enters the vapor chamber, the vapor rises and is piped into the previous stage evaporator to be used as the heat source, while the oil sludge mixture falls to the bottom of the chamber and is pumped to the fol lowing stage evaporator. This multi-effect evaporation saves steam over si ngle-effect operations through the reuse of heat. A vacuum is applied to each effect to reduce the temperature required to vaporize the water in the sludge. Most proposals on treating municipal sludge with the Carver-Greenfield process include an incinerator or pyrolysis reactor to recover the heat value of the dried product. Theoretically, this is an attractive combination of processes, since water can be evaporated prior to combustion or gasif ication. Fuel gases produced during pyrolysis, or waste heat from an incinerator can then be used to supply the energy requirements of the Carver-Greenf ield process. The process also can be used to produce a fertilizer. Odors , sidestreams containing ammonia and dissolved organics, and the requirement of large quantities of make-up oil represent possible problems associated with the Carver-Greenfield process. In summary, the Carver-Greenfield process offers considerable potential for improved thermal efficiency of subsequent combustion processes. This is because water is evaporated with multiple-effect efficiency as opposed to single-ef fect evaporation which normally occurs in other heat drying processes. The potential exists for making the sludge processing train energy self-sufficient and, perhaps, energy producing. However, this is accomplished with a large capital investment. While the Carver -Greenf ie ld process is used in many industrial applications, it has not been adequately demonstrated for the treatment of municipal sludges. 120 CONDENSATE", TO PLANT 0 0 0 z CONDENSER z rn m z (n rq STEAM STEAM STEAM STE FLUIDIZING FIRST SECOND THIRD SLUDGE GRINDER SLUDGE OIL SLUDGE/ SLUDGE/ FEED TANK EFFECT OIL EFFECT OIL EFFECT AL ul U) --- RECYCLE OIL OIL/ WATER WATER /OIL CENTRIFUGE SEPARATOR WATER RETURN DRY SOLIDS TO PLANT Oil CARVER -GREENFIELD MULTI-EFFECT EVAPORATION PROCESS SOURCE: Manufacturerls Data "49 See Detail "A; TUBE 000 0 000000 0000000 TUBESff, FALLING FILM EVAP. 000 000 TUBE NEST 0 J'Ili 0 00 O;iio VAPOR 00 000 0', -SLURRY 0 0 0 0 0 0 0 0000,00 .0. ST6-;q/vl ID -ryp 000 @Lji 0 DETAIL"A's SEC771ON"B@-"B" Grophle Representation Of Slurry Flow Typical Plan View Of Tube TO In A Falling Film Evaporator Nest Pattern 2nd@--@ .Stage 2nd Effi@ct STEAM IN ),Not CONDENSATE q6P 3rd STAGE Ist EFFECT j- 0 r 0 'H 111APOH CHAYHER FALLING FILM EVAPORATOR DETAILS From Transfer Pump To Circulation Pump SOURCE:. Los Angeles County/Orange County Sludge Processing and Disposal, April 1977, p. 6-35 1 1 0 0 41 a a a 4b Solvent Extraction Dehydration (B.E.S.T. System) The Basic Extractive Sludge Treatment (B.E.S.T.) process uses an aliphatic amine solvent to separate sludge solids from water. The process functions based on the tempera t ure-sens it ive properties of the solvent. Below 650F., the solvent and water form a single-phase, homogeneous solution. Above 65 0 F. , the solvent and water mixture separates into two distinct layers, the bottom one being almost entirely water. On entering the system, the inlet sludge is cooled to about 0 500F., before joining the solvent which has also been cooled to about 20 F.(see Figure 23) . Due to the heat of reaction, the temperature of the mixture increases to about 60 0F. , and is subsequently cooled to about 50 0 F. in a third heat exchanger to ensure that the temperature of the mixture is below the critical point of 65 0F. The sludge/solvent mixture then enters a centrifuge where the solids are removed and sent to a dryer. The solvent remaining with the solids is driven of f in the dryer, condensed, and returned to the system. The water solvent fraction or centrate is heated to 120 0 F. , and sent to a decanter where the solvent and water separate. The solvent is returned to the system and the water is fed to a steam stripping distillation column to recover and recycle the remaining fraction of solvent. Any oils or fats extracted from the sludge remain in the solvent and are recovered in a solvent still. Oils and fats are left to be collected and disposed of separately. The B.E.S.T. process is still experimental. Foam, odors, excessive centrifuge capacity, and heat exchanger plugging are a few problems which have yet to be resolved. The advantages of the B.E.S.T. proces s are lower energy costs, smaller amounts of exhaust gas and a fairly clean, low-volume sidestream. 123 B.E.S.T. PROCESS FLOW SCHEMATIC Boo F STERILE DRY SLUDGE 500F SOLIDS NX re ".w @w Mae DAYER mm @w so* am me am @n ft"M 4ftv "WAM -40. 1600 F I 600F 0-6 Mw * x CENTRIFUGE 501F 120OF WATER HX NX DECANTER STILL -10I. 200 F STERILE CLEAR WATER 1200F SOLIDS SOLVENT WATER STILL SOLVENT OIL SOURCE: EPA, Process Design Manual Sludge Treatment and Disposal, September, 1979, p. 10-29 .@WATER 200 F '-fANTER STILL Fj THERMAL REDUCTION CASE STUDY CARVER-GREENFIELD PROCESS LOCATION: (Current and under construction): Industrial:Coors Brewery, Colorado, Hershey Chocolate Company, Pennslyvania Municipal: Fukuchiyama, Japan City of Los Angeles, Step 1, 2: 657 tons/day (Spring '86); Trenton, New Jersey (under design) OPERATOR: Foster-Wheeler, Inc. with DeHydrotech Corporation PROCESS TYPE: Dehydration of previously thickened or dewatered industrial and municipal sludges via multiple-effect evaporation in a light oil medium. CAPACITY: From 40 tons per day to 400 tons per day. Can be combined with energy recovery in steam and electric generating plant. Below 30 tons per day, must be custom designed without energy recovery. SITE AREA: For Carver-Gr6enfield alone, an 82 tons per day plant uses approximately 6,200 square feet DRIED SLUDGE CAKE: Up to 99 percent solids. Can be re-watered to desired moisture content, or pelletized to enhance combustion characteristics. DISCUSSION The Carver-Greenf ield process has been in use in the food and chemical industry over the last several decades, principally for the dehydration and disposal of unusual wastes that resist conventional treatment, such as from breweries and paper mills. Although as yet largely undemonstrated for municipal wastes, except for a night soil* plant in Japan, a large, integrated energy recovery facility is about to undergo startup for the City of Los Angeles. Other proposals are being considered for Trenton and other New Jersey localities, and by the City of Syracuse, New York. Night soil is excrement removed from privy vaults and used for fertilizer. 125 The major advantage claimed for the process is energy efficiency, based on the principle of multiple-effect evaporation. Through a series of recondensations an equivalent of three or more pounds of vapor is evaporated for each pound of input steam into the process. The light oil carrier provides a secondary source of energy. The light oil dissolves scum and residual oils in the sludge and makes them available for combustion to support the process and make it practically self-sustaining. The product can be brought to near 100 percent dryness if desired, and is essentially odor-free and innocuous except for inherent heavy metal content. Additionally, the low moisture content of the dehydrated sludge makes all its heating value available for combustion. This allows any proportional mixture of dehydrated sludge-and municipal solid waste. Energy recovered from the combustion process can be sold to a local utility, reducing the cost to dispose of the sludge. The complexity of the Carver-Greenfield plant is a disadvantage. It requires more costly maintenance and more advanced operating technology than a typical sewage plant. There is also an increased chance of operating failure. The condensate from the various evaporator stages makes up a sidestream that must be sent back to the sewage treatment plant for treatment, and may consititute a significant biochemical oxygen demand (BOD) load. The effect of energy recovery on operating cost is illustrated by Table 36. This shows a breakdown of the cost elements before and after energy recovery in two plants in New Jersey for which f irm quotations are available from the manufacturer, and a third hypothetical plant using fluidized bed combution, based on a US Department of Energy- sponsored study. Note that the cost per dry ton for disposing of sludge can be decreased by .27 to 51 percent, if energy recovery is employed even at the $.06 per KWH used for this analysis. Below 30 tons per day this option is not effective. The final costs are quite sensitive to the degree of dryness of the input sludge, as less water will then have to be removed by the Carver-Greenf ield process. Even if energy is not recovered the cost per ton is quite competitive with other current technologies. 126 TABLE 36 CARVER-GREENFIELD DEHYDRATION WITH ENERGY RECOVERY 60 TONS/DAY' 82 TONS/DAY b 50 TONS/DAY' (press to 35 %) centrifuge to A5%)(centrifugecto 12%) COST ITEM $1000 ($/dt)' $1000 ($/dt) $1000 ($/dt) Capital Dewatering 788 ( 5.98) 2,995 ( 10.05) 1,134 ( 3.43) Carver-Greenfield 5,250 ( 39.81) 8,023 ( 26.99) 11,736 ( 35.58) Energy Recovery 3,465 ( 26.26) 8,132 27.38)_ 9,450 ( 28.66) Total Capital $9,503 19,150 $22,320 Annual Capital Cost 1,578 ( 72.05) 1,928 64.42) 3,705 ( 67.67) Operating & Maintenance: Dewatering 804 ( 36.71) --- --- 886 16.18) Carver-Greenfield 544 24.84) --- --- 720 13.15) Energy Recovery 496 22.65) 720 13.15) Total O&M 1,844 84.20) 1,836 61.34) 2,326 42.48) Total Annual Capital & Operating Cost: 3,422 (156.25) 3,764 (125.76) 6,031 (110.15) Credit for Energy Recovered: Steam @ $5.50/M lbs 788 ( 35.52) --- --- --- --- Elec. @$ .06/KWH 137 ( 6.26) 1,932 ( 64.55) 2,286 ( 41.75) Total Energy Credit 915 ( 41.78) 1,932 ( 64.55) 2,286 ( 41.75) Net Cost: 2,507 (114.47) 1,832 ( 61.21) 3,745 ( 68.40) Decrease in cost from energy recycing 26.7) 51.3) 37.9) NOTES: a: from communication, DeHydrotech Corp. b: from Sludge-to-Energy Feasibility Study, NYC Department of Environmental Protection, (funded by US Department of Energy), in publication, 1986. c: based on Annual Capital Charge of 16.6 percent (own and operate lease by manufacturer) d: based on Annual Capital Charge of 7 percent municipal bonds (owned by any municipality) 127. THERMAL REDUCTION INCINERATION CASE STUDY LOCATION: Glen Cove, New York OPERATOR: mmb Glen Cove Corporation (subsidiary of Montenay International Corp.) PROCESS TYPE: Mass burn refractory furnace Co-disposal of municipal solid waste (MSW) and municipal sewage sludge CAPACITY: 250 tons per day (TPD) (225 TPD MSW, 25 TPD sludge, in two parallel process trains) SITE AREA: Two acres DRIED SLUDGE CAKE: 20 percent solids SLUDGE DEWATERING: Centrifuge (2 units) CAPITAL COST: $24 million DISCUSSION Technical representatives from Orange and Rockland counties and EFC staff toured this facility on January 28, 1986. Both the resource recovery facility and the sewage treatment plant are operated by mmb Corporation under a contract with the City of Glen Cove. The operation appeared to be well run and efficient. Unsorted MSW is received at the facility, and transported by compactors and other vehicles. Large, non-combustibles (stoves, refrigerators, etc.) are separated on the tipping floor and combustible refuse is dropped into a receiving bin. The MSW is then fed as needed into a charging hopper for the stoker by a radio controlled gantry crane. Sludge is simply dropped onto the MSW in the charging hopper by an oscillating nozzle. The rate of sludge feed is controlled by the speed of a progressive cavity cake pump fed from a dewatered sludge storage hopper. Sludge feed rate is a function of furnace temperature and sludge solids concentration. The MSW/sludge mixture is then conveyed into the furnace by the stoker. Heat generated in the combustion process at 1600 0F is used to make steam to power a five stage, 3,600 Hp turbine which drives a 2,500 KW electrical alternator. The power generated is used to supply the resource recovery facility as well as provide electric power for the STP. Approximately 50 percent of the electricity generated is sold to the Long Island Lighting Company at approximately $.07/kilowatthour. 128 The facility generates approxmately 44 tons of ash when operat.ing at design capacity. Sixty to 70 percent of the ferrous metals are recovered by a magnetic drum separator. The ash is being landfilled. A future plan is to further refine the ash residue for use as roadbed material, concrete block, and similar uses. The only significant problem at the facility appeared to be the ability of the centrifuges to deliver a consistent-20 percent sludge cake. Currently, the sludge cake averages 15 to 20 percent . The use of a belt press to dewater sludge is being considered to increase sludge solids concentration. It is be lieved that, with proper operation, a belt press may achieve 25 to 30 percent solids, resulting in considerably higher heat' values (Btu/Ib) per ton of sludge burned. An outstanding feature of the facility appeared to be the simplicity in the MSW/sludge mixing process. Such a simple system could easily lend itself to being retrofitted for existing and planned resource recovery facilities. This facility qualified as "innovative technology", making it eligible to receive 92.5 percent of its funding from federal and state grant progratms. With this as a precendent, similar funding level's may be available for regional projects. 129 00 Summary Thermal reduction processes have been used frequently in the sludge disposal field. Incineration represents the current, established technology which results in reliable sludge disposal systems. Pyrolysis and starved air combustion systems represent an attempt to make the incineration process more efficient. To date, full-scale pyrolysis of sl udge has not been as reliable as incineration systems. It does, however, offer several advantages over incineration which may result eventually in continued research and testing to produce a more reliable and efficient pyrolysis system. 130 CONSIDERATIONS COMMON TO TECHNICAL ALTERNATIVES Introduction Thre are several issues common to the consideration of any of the technologies proposed in this report: dewatering sludge, transporting the sludge and providing for other wastestreams as a result of sludge management processes. This section describes each issue. Various types of sludge dewatering equipment are presented as well as recommendations for dewatering in connection with all technical alternatives. Some general comments about transporting sludge are provided to give the reader a sense of the items to be considered. Sludge Dewatering Sludge dewatering is often the primary step in sludge treatment and d i s p o s a I .It is used to decrease the volume of sludge requiring disposal by removing as much water as possible. Land-based methods for sludge dewatering (drying beds and lagoons) were commonly used in the past. However, for large volumes of sludge such methods require large land areas and are extremely labor intensive. Additionally, most drying methods employed to handle large volumes of sludge are mechanical. Three methods which have proven to be both efficient and economical are outlined here: centrifuge, belt filer press, and plate and frame filter press. Vacuum filters and drying beds are briefly discussed as these methods are used presently in the region. However, their use in a regional project would not be appropriate. Centrifugation Centrifugation has been practiced as a sludge dewatering process since the early 1900s. As indicated by the process name, the centrifuge uses centrifugal force to accelerate the sedimentation rate of the sludge s o I i d s .There are three basic types of centrifuge used for sludge dewatering: basket, solid bowl conveyor and disc nozzle. The basket centrifuge incorporates a solid bowl which rotates around a vertical axis. It operates as a batch process. Sludge and polymer are fed into the base of the rotating bowl. Sludge solids migrate to the exterior wal Is of the bowl, while centrate (clarified liquid) overflows an internal weir (level control device to separate liquids by density) and is discharged back to the primary or secondary portion of the plant. The process continues until the quality of the centrate deteriorates, indicating that the basket is overloaded with solids. At that point, the sludge feed to the unit closes, and a skimming cycle begins collecting the sol ids, still too wet to transport, and directing them to a holding tank or back to the primary or secondary treatment process. Following skimming, a knife scrapes the basket of the centrifuge dislodging the dewatered solids and allowing them to fall out of the basket bottom for conveyance to a discharge point. The cycle is now completed and sludge can once again be fed into the machine. A schematic of the basket centrifuge porcess is shown in Figure 24. 131 FIGURE 24 BASKET CENTRIFUGE SCHEMATIC DIAGRAM FEED POLYMER SKIMM INGS NIFE ATE CAKE CAKE SOURCE: "Process Design for Sludge Treatment and Disposal", USEPA 625/1-79-011, Sept. 1979, p. 5-46 132 The solid bowl conveyor centrifuge process is continuous. It consists of a s olid bowl and an inner screw conveyor as shown in Figure 25. Sludge and polymer are fed into the center of one end of the centrifuge. Sludge particles migrate to the outside of the rotating bowl, forminga. conc entrated mixture. This sludge mixture is then conveyed by the screw to -one end of the unit and discharged. At the same time, the centrate moves counter-currently to the solids, discharging at the opposite end of the centrifuge. The disc nozzle centrifuge is a solid bowl which rotates on a vertical axis (similar to the basket centrifuge) bu't operates in a continuous feed. Figure 26 illustrates the disc nozzle unit operation. Sludge is fed into the top of the centrifuge and forced through a series of closely spaced d i s c s .Centrifugal force pushes the solids against the unit periphery where they are discharged through a series of nozzles. Centrate continues upward through the discs and is discharged over a fixed weir. Experience with Centrifuges Each centrifuge has been used with various types of sludge. In general, the operation is clear and simple. However, centrifuges have been plagued with problems including high power consumption, excessive wear of rotating parts, clogging (a problem limited mostly to the disc nozzle type) and plant upset caused by centrate recycling. Recent advances in centrifuge technology have helped to mitigate some of the earlier problems. Newer dewatering installations have been lmited to the solid bowl conveyor centrifuge in hopes of providing continuous, non-clog operations. Slow speed drives, high technology wear-resistant metals and a greater understanding of polymers have essentially eliminated some of the earlier problems these machines suffered. The centrifuge, as all dewatering processes, requires a considerable amount of ancillary equipment for operation. It is important that grit 'removal be incorporated prior to the centrifugation process, as grit will cause extensive wear of the centrifuge's internal parts. The solid bowl conveyor centrifuge can produce dewatering results equal to any other dewatering unit. Solids concentrations from 12 to 60 percent are possible, based on the type of sludge dewatered and the amount of polymer used. Table 37 outlines solids concentrations which can be expected for various types of sludge. Projected solids capture for the solid bowl conveyor centrifuge can vary from 30 to 95 percent depending on the type of sludge treated and the amount of polymer used. The amount of solids capture has a considerable effect on the quality of the centrate that must be handled. Centrate strength can range from 500 to 2,000 milligrams per liter suspended solids and 100 to 1,000 milligrams per liter chemical oxygen demand (COD). 133 FiGuRE 25 --MEL FEED ROTATING fir CONVEYOR 6E 0/( ROTATING BOWL CENTRATE COVER DEWATERED SOLIDS SCHEMATIC OF TYPICAL SOLID BOWL DECANTER CENTRIFUGE SOURCE: "Process Design Manual for Sludge Treatment and Disposal", USEPA 625/1-79-001, Sept. 1979, p. 5-50 /z 77% 14, I 7W41 134 FIGURE-26 DISC TYPE CENTRIFUGE FEED EFFLUENT DISCHARGE ------- -SLUDGE DISCHARGE SOURCE: "Process Design for Sludge Treatment and Disposal", USEPA 625/1-79-011, Sept. 1979, p. 5-41 135 TABLE 37 Sludge Concentration Produced by Centrifugal Dewatering Solid Bowl Sludge Conveyor Centrifuge (% TS) RP or DP 28-35 RP + TF 20-26 RP + AS 18-24 AS 12-15 Lime sludge 45-60 Alum sludge 15-25 Heat treated sludges 30-40 Key: R = raw; P = primary; TF trickling filter; AS = activated sludge; and DP = anaerobic digested primary. SOURCEz Water Pollution Control Federation, Manual of Practice No. 8 136 Belt Press Until recently, belt presses were used in this country only for industrial applications. Today, the belt press is commonly used as a sludge dewatering unit. The process essentially consists of two belts guided by several rollers or drums. Sludge is fed onto the lower belt, travels through the press and is physically squeezed between the two belts as shown in Figure 27. Two processes actually take place as sludge travels through the unit. In the early stage, "free water" is drained by gravity. Following that, a pressure phase, in which the two belts are brought close together to create pressure on the sludge, squeezes water through the pores of the filter belt. The belt press process is continuous, offering similar dewatering capability to that provided by the centrifuge, while requiring less horsepower for operation. Degritting sludge is as critical a pretreatment for the belt press as for the centrifuge. Addition of polymer is a must to aid the release of water. Polymer dosage depends largely on the type of sludge to be dewatered and the desired solids concentration in the sludge. Although the sludge press consists of many moving parts, the filter 'belt itself is most susceptible to wear as well as blinding (plugging of the belt pores). It is important tha t a constant flow of clear wash water be directed on-the belt to cleanse it of solids particles. In addition to polymer feed and wash water, the belt press requires ancillary equipment similar to -the centrifuge. Figure 28 illustrates a typical belt press installation. Several modifications are available such as high pressure sections and vacuum assisted sections, which can be added to a press to help obtain a more concentrated sludge. Table 38 outlines expected belt press dewatering results. It should be noted that with a belt press, solids capture is normally 90 percent or better, resulting in lower solids and COD centrations in the filtrate (equivalent to centrate) than can be obtained iri the centrifuge. Plate and Frame Filter Press The plate and frame filter press was developed in Europe and Japan and has been used sparingly in the United States. There are many varieties, but al I operate on the principle of pressure filtration. Several vertical plates are mounted on a frame in a horizontal plane (see Figure 29). When horizontal pressure is applied, the plates lock together, forming a group as shown in Figure 30. A filter cloth is located on the face of each plate forming a continuous filter cloth envelope within each plat.e. Sludge is fed through a horizontal pipeline on the axis of the p I a t e s .Sludge enters each plate or filter cloth envelope. As the sludge is pressurized, water is forced out through the filter cloth and collected in a filtrate pipeline. Dewatered s .ludge collects on the filter cloth surface. After. one to four hours, pressure is then released, the plates are separated and dewatered sludge falls into a hopper for disposal. 137 FIGURE 27 C14EMICAL GnAVITY COMPRESSION CONDITIONAL DRAINAGE DEWATERING STAGE STAGE STAGE POLYELECTROLITE SOLUTION SLUDGE --Ob. MIXER CONDITIONED - 0- 0 SLUDGE 00 Jill.' WASH SPRAY SLUDGE FILTRATE CAKE WASH WATER THE THREE BASIC STAGES OF A BELT PRESS SOURCE: "Process Design for Sludge TreatMent and Disposal", USEPA 625/1-79-011, Sept. 1979, P.9-46 rIONeD F 138 FIGURE 28 POLYMER POLYMER POLYMER STORAGE FEED TRANSFER TANK PUMP PUMP WASH POLYMER WATER DAY TANK PUMP PLANT EFFLUE-Ni ED+--FLUSNING WATEF + CAKE TO FINAL BELT PRESS PROCESSING SLUDGE FEED SLUDGE PUMP IOLDING TANK- FILTRATE AND WASH WATER TO PLANT AIR COMPRESSOR BELT PRESS DEWATERING PROCESS SOURCE: "Sludge Processing and DIsposal", Los Angeles County/orange County Sanitation Districs, April, 1977. 1 :ES S@ 0 SLUDC 139 TYPICAL DEWATERING PERFORMANCE OF BELT FILTER PRESSES Polymer, Feed Cake, pounds dry solids, perceht per ton Type of sludge percent solids dry solids Raw primary, (P) 3-10 28-44 2-9 Waste activated sludge (WAS) 1-3 16-32 2-4 0.5-1.5 12-28. 4-12 P + WAS 3-6 20-35 2-10 P + trickling filter (TF) 3-6 20-40 3-1.0 Anaerobicaily digested P 4-10 26-36 2-6 WAS 3-4 18-22 4-8 P + WAS 3-9 18-44 3-9 Aerobically digested P + WAS 1-3 12-18 4-8 6-8 20-30 2-5 Thermal conditioned P + WAS 4-8 38-50 0 00 SOURCE: "Process Design for Sludge Treatment and DIsposal", USEPA 625/1-79-011, Sept. 1979, P. 9-48. ML Ah db 40 0 FIGURE 29 FIXED OR MOVEABLE FEED HEAD PLATES HEAD CLOSING CLOSURE HEAD HYDRAULIC SCHEMATIC SIDE VIEW OF A RECESSED PLATE PRESSURE FILTER SOURCE: "Process Design for Sludge Treatment and Disposal", USEPA 625/1-79-011, Sept. 1979, p. 9-53 141 FIGURE 30 PLATE-FRAME FILTER PRESS 7/77 FILTRATE X % :X X. X. ...... ....... %... .... UNFILTERED SLUDGE X. % Xv: -*X x . . % SOURCE: "Sludge Processing and Disposal", Los Angeles County/Orange County Sanitation Districtsq April 19779 p. 5-8 142 Several types of plate and frame presses are available. They are generally described as high or low pressure and fixed or variable volume. The low pressure units operate at approximately 100 pounds per square inch (psi), while high pressure units are operated at 220 to 250 psi. Fixed volume units are operated as described above. The sludge itself is pressurized and the process continues until the plates are packed full of dewatered sludge. A variable volume press contains a rubber diaphragm placed behind the filter cloth. Sludge is fed into each plate until the plates are full. Pressure is then applied to the area between the diaphragms, resulting in the application of pressure on the sludge. Sludge and filtrate are collected in a similar manner for each type of press. Plate and frame filter presses require considerable sludge conditioning to produce a manageable sludge product. It is common to use a combination of ferric chloride, lime, ash or polymer to produce an acceptable sludge. These substances increase the ability of sludge to be dewatered. Sludge can be dewatered without the use of polymers. However, sludge is difficult to remove from the plate and can require a considerable amount of additional labor. It is good practice to include an acid wash system to clean the plates and filter cloth of the sludge chemcial mixture. Figure 31 illustrates the equipment required for a typical plate and frame installation. Because of the equipment, the fact that it is a batch process, the extensive amount of labor required to operate the system, and rel atively high energy costs, this process is usually used only when a high level of dewatering is.required to incinerate a sludge of limited dewaterability, such as waste activated sludge (excess solids removed from the treatment process for disposal). Typical solids concentrations from the use of plate and frame filter presses are shown in Tables 39 and 40. Variable volume presses perform slightly better than the fixed volume press. Filtrate from the plate and frame filter press is relatively low in pollutant concentration, similar to the belt press. Solids capture is typically above 90 percent. Air Dry ng Air- drying of sludge is accomplished by placing liquid sludge on specially constructed drying beds. Sludge dries on beds by evaporation of moisture and gravity drainage to an underlying, perforated pipe drainage system. This drainage is then returned to the plant process for treatment. (See Figure 32, typical sludge drying bed construction.), Drying beds are land-and labor-intensive since sizeable areas are required and drying beds are generally cleaned by hand. For these reasons, sludge dry ing beds are generally used only at plants less than one million gallons per day (mgd) capacity. Despite occasional claims to the contrary, sludge wil 1 not dry on beds when frozen. Therefore, approximately four months of storage- is required to accommodate the winter months. For adequate performance, sludge drying beds should be-roofed to prevent rainfall from entering but not enclosed so that adequate ventilation is available. 143 FIGURE 31 LIME' CHEMIGAL FEED PUMPS SrORAGE7 rERnIC CIOLOMDE TANK -0 STOFIAGE TANK SLUDGE SLUDGE TRANSFER FEED, PUMP PUMP FILTER PRESS FILTRATE TO PLANI SLUDGE SLUDGE. HOLDING CONDITIONING CAKE TO TANK TANK FINAL PROCESSIN G ACID ACID WASH ACID TRANSFER ACID PUMP SOLUTION PUMP STORAGE TANK TANK CONVENTIONAL LOW PRESSURE (100 PSI) FILTER PRESS SYSTEM SOURCE: "Sludge Processing and-Disposal@.,Los-..Ang-e-le-s--County/Orange County Sanitation Districts, April 1977. @AC I @D@@ ACID 144 TABLE 39 TYPICAL DEWATERING PERFORMANCE OF A VARIABLE VOLUME RECESSED PLATE PRESSURE FILTER Chemica I dosage,a lb/ton dry Percent solids Feed solids solids Yield, Cake WLth Cake without Site Type of sludge percen@ FeC13 a Ca& lb/sq ft/hr chemicals chemicals .b Anaerobically digestea 1 60 P ;40 WAS 3.8 120 320 1.0 37 30 2 60 P: 40 WAS 3.2 180 Sao 0.7 36 25 3 40 P: 60 WAS 3.8 120 340 0.6 40 12 4 40 P: 60 WAS 2.5 ISO 500 0.6 42 30 5 50 P: 50 WAS 6.4 so 220 2.0 45 39 6 60 P: 40 WAS 3.6 160 320 0.8 50 40 Raw WAS 4.3 180 460 0.6 34 25 a Raw (60 plus 40 WAS) 4.0 100 300 0.9 40 33 9 Thermal conditioned 50 P: 50 WAS 14.0 0 0 2.5 60 60 aAll values shown are for pure ferric chloride and lime. Must be adjusted for anything else. bp = primary sludge; WAS = waste-activated sludge. 1 lb/ton = 0.5 kilograms/ton 1 lb/sq. ft./hr. - 4.9 kg/m 2 /hr. SOURCE: "Process Design for Sludge Treatment and Disposal", USEPA 625/1-79-011, September 1979, p. 9-56 145 TABLE 40., EXPECTED DEWATERING PERFORMANCE FOR A TYPICAL FIXED VOLUME RECESSED PLATE PRESSURE FILTER Cake with Cake without Conditia-xing dosage, conditioning conditioning Feed lbs/tcn dry solics material, material, Cycle solids, a a percent percent tire, Tvr,e of sludge percent Fecl cao Ash solids solids hours 3 Raw prLwry (P) 5-10 100 200 45 39 2.0 2,000 50 25 1.5 Raw P with less than 3-6 100 200 45 39 2.5 50 oercent waste 3.000 50 20 2.o activated sludoe (WAS) Raw P with more than 1-4 120 240 45 38 2.5 50 percent WAS 4,00() 50 17 2.o Anaerobically digested mixture of P and WAS Less than 50 Percent wAs 6-10 100 200 45 39 2.0 2. 000 50 25 1.5 more than 50 percent WAS 2-6 150 300 45 37 2.5 4,000 50 17 1.5 Ms 1-5 150 300 45 37 2.5 51000 50 14 2.o aAll. values shown are f or pur6, y erric chloride and lime. Must be adjusted f or anything else. 1 lb/ton = 0.5 kilograms/ton 1 lb/sq. ft./hr. = 4.9 kg/m2/hr.' Ah SOURCE: "Process Design for Sludge Treatment and Disposal", USEPA 625/1-79-011, September 1979, p. 9-56 146 FIGURE 32 SLUDGE 'GATE SIDE WALL SPLA'SH SLA8 COLLECTION SYSTEM DRAINAGE AV Typical sludge drying bed construction. SOURCE: "Operations Manual: Sludge Handling and Conditions USEPA 430/9-78-002, February 1978, PX 11 2 LUDGE 147 Vacuum Filter Often used in the past as a dewatering device, vacuum filters have passed out of favor because of high operating costs (energy, chemicals, and labor) and their inability to compete with other methods in terms of cake dryness. While some vacuum f ilters are used in the region now, upgrading this equipment to belt presses is recommended where economic factors warrant. Basically, a. vacuum filter consists of a large cylindrical drum covered with a "filter" (fabric or coil). The lower third of the drum is rotated through a trough of sludge and a vacuum is applied to the inside of the filtered drum. As the drum rotates in the sludge, sludge is drawn onto the drum by the vacuum and moisture is drawn through the sludge and drum cover. At a certain point, the dried sludge is scraped from the drum onto a conveyor while the drum rotates. Sludge is again drawn onto the drum and the process is repeated. Figure 33 shows a rotary drum vacuum filter. Comparison of Dewatering Processes Table 41 is a comparison of the advantages and disadvantages of all the dewatering processes described previously. 148 ROTARY DRUM VACUUM FILTER CLOTH CAULKING STRIPS DRUM AUTOMATIC VALVE FILTRATE PIPING F" CAKE SCRAPER AIR AND FILTRAT LINE SLURRY AGITATOR r I VAT SLURRY FEED AIR BLOW-BACK LINE SOURCE: "Sludge Processing and Disposal", Los Angeles County/Orange County Sanitation Districts, April 1977, p.57713 TABLE 41 CONPARISON OF DEWATERING PROCESSES Process Advantages Disadvantages Centrifuge Disc nozzle Yields highly clarified Must use sludge with centrate without chemical particle size of 400 conditioning. Large liquid microns or less. & solids handling capacity Requires extensive pre- in a small space. Produces screening & grit removal. little odor. Can produce Requires skilled sludge solids concentrations operators. up to 6 percent. Continuous operation. Basket Same machine can be used Unit is a batch process. to thicken and dewater. Has highest capital cost Has lowest O&M costs of to capacity ratio. the centrifuges. Can Requires extensive thicken hard-to-handle structural support. sludges. Little odor. Performance affected by Can produce solids con- solids feed rate. centrations of 10 percent. Best for small plants,l to 2 million gallons/day. Solid Bowl Yield high throughout in a Can have high maintenance .Conveyor small area. Is quiet and costs. easy to install. Produces May require polymers to no odor. Low capital cost. operate. Requires . Can produce solids con- skilled operators and centrations to 8 percent. maintenance personnel. Continuous operation. Requires grit removal. Belt Filter Press Continuous operation. Needs chemical Cake concentrations to 44 conditioning. Sensitive percent are possible. to sludge feed Lower power requirements characteristics. than other mechanical pro- cesses. Pressure Filters Especially effective on Chemcial conditioning waste activated sludge sometimes required. May get sludge cake up Batch process. to 50 percent solids. 150 Conclusions Sludge dewatering is most effectively accomplished by mechanical means at sewage treatment plants of about one million gallons per day (mgd) capacity and above. Currently centrifuges and filter presses are the most efficient mechanical dewatering devices available. Although some STPs in the region use vacuum filters, high energy, chemical, and labor costs, coupled with low solids content of vacuum filtered sludge (usually less than 20 percent), have made vacuum filters a poor choice. Air drying of sludge, a non-mechanical dewatering process, is appropriate only at very small plants because of the relatively large land area needed to construct drying beds, the labor intensity of the process, and the storage capacity required during periods when air temperatures are below freezing. The type of mechanical dewatering device used depends on the level of dewatering (percent solids) desired and the type and nature of sludge to be dewatered. In EFC's experience, belt filtration is preferred over centrifugation in most cases for the following reasons: Lower operation and maintenance costs Higher reliability Higher cake solids of dewatered sludge Simplicity of operation. The belt filter press is recommended in all cases except when sludge solids concentrations of 35 percent or greater are required. The reasons for recommending belt presses over plate and frame presses are the same as those listed above with the exception of the third item. Dec isions regarding dewatering are primarily based on the ultimate disposal option being used and the related transportation costs. In general, dewatering sludge substantially reduces the volume to be transported. Devatering and Technical Alternatives The following is a brief discussion of dewatering in terms of the specific disposal alternatives considered in this report. Landfill Dewatering to at least 20 percent solids is required by NYSDEC regulations. Dewatering to greater than 20 percent is desirable to conserve available landfill space and reduce the amount of moisture which can contribute to leachate formation.. Dewatering to 20 percent solids increases the costs of chemicals and labor, but generally results in lower transportation costs and tipping fees to dispose at the landfill. 151 Ocean Disposal Currently sludge is barged to sea from the Yonkers STP at two to three percent solids. This means that1 97 to 98 percent of this sludge is water. Previous engineering studies conducted for Westchester County have recommended sludge dewatering prior to ocean disposal. While dewatering may appear to be an obvious advantage, several factors must be considered regarding dewatering in this instance. 1. Retrofitting existing barges will be necessary as these vessels are equipped with pumps to discharge sludge at two to three percent solids. These pumps will be limited by the solids concentration they can pump. If sludge is dewatered to greater than 18 to 20 percent solids, equipment in the form of cranes, conveyors, etc., will be required. 2. As a result of public pressure local officials have adopted a policy no t to expand the Yonkers STP. The addition of dewatering equipment to the plant could be considered "expansion" and not acceptable under the terms of this policy. 3. Recently negotiated contracts for barging sludge probably specify the consistency of the sludge. Such contractual terms may be difficult or impossible to renegotiate. Land Application Generally, sludge is land applied as a liquid (two to five percent solids). However, equipme nt is available to land apply sludge at virtually any level of dryness. One advantage of liquid application is that the sludge may be con tinuously enclosed, thereby reducing or eliminating odors. The question of whether to dewater sludge destined for land application is generally a straightforward economic one of, dewatering costs versus transportation costs. Composting The composting process requires that sludge be dewatered to at least 20 percent solids. H igher solids concentrations are generally desirable as less bulking agent is required. Thermal Reduction Dewatering for thermal reduction is absolutely essential. Depending on the type of reduction process employed and the volatile solids ratio of the sludge, dewa 'tering to 23 percent to 35 percent or more is necessary for efficient combustion. USEPA studies cited elsewhere in this report describe cost reductions on the order of 50 percent when dewatering is improved to optimum levels. The optimum level is the point at which the sludge will be autogenous (capable of combustion without an external fuel source). 152 Transporting Sludge Methods of-Transport Sludge may be transported four ways: truck,.pipeline, barge, and rail. The method of transport is a function of three primary variables: use and dis posal method (land application, landfilling, sludge product distribution, and marketing, incineration, ocean disposal), volume and solids content of sludge, and distance to and number of destination points. Truck Transport -Trucks can be used to haul both liquid and dewatered sludge. Truck transport can be attractive because: routes and terminal points are flexible and can be changed at low cost, no intermediate storage or pumping steps are necessary, and equipment may be owned by the plant or leased. Trucks come in a variety of sizes with special features available such as spreaders, auger beaters and subsoil injectors for various methods of application. Diesel-fueled trucks are the most economical if larger sized vehicles are needed or if high annual mileage is anticipated. The economic limits for hauling sludge by truck over distance depend on the degree to which it has been dewatered. However, the cost of dewatering the sludge must be factored in when evaluating the apparent savings in hauling a drier sludge. Truck hauling can be the most economical way to transport sludge at distances less than 150 miles. Total costs include the size of the fleet plus mileage. Liquid sludge is transported 'in tank trucks which are designed in the following capacities: 1,600, 2,000, 2,500, 3,000, 4,000 and 6,000 gallons. State laws determine tanker dimensions and maximum load. However, liquid sludge is usually hauled in tanks less than 6,000 gallons. The volume selected depends on loading and unloading times, haul distance and trip frequency. Dewatered sludge is hauled in open trucks with capacities ranging from seven to 36 cubic yards. As with tank trucks used for hauling liquid sludge, maximum truck loads are set by state laws. Trucks are used in conjunction with pipeline or railroad to an intermediate storage facility and used to haul sludge to an incinerator, or haul residual ash from an incinerator to a landfill. The number of trucks necessary for a given plant is a function of truck capacity, volume of sludge to be hauled, and travel and unloading time ' with the last two variables directly related to distance from the plant to the destination point. 153 Environmental Impacts of Truck Transport Care must be taken to minimize the environmental impacts caused by truck transport. Sp ills must be prevented during loading and unloading of both tankers and open standard highway trucks. Standard trucks used for hauling dewatered sludge should be equipped with watertight seals which are not necessary for hauling very dry or composted sludge (greater than 50 percent s o 1 i d s ) .Trucks hauling dewatered sludge are generally fitted with tarpaulins during transit. Minimizing Equipment Cost of Truck Transport The cost of operating hauling equipment can be minimized by making maximum use of the vehicle. However, vehicle use is limited by certain variables such as the amount of light available for daylight trucking operations. Because most truck crews work the dayshift, this eight hour period may not be sufficient to haul the daily volume of sludge generated. For this reason, short-term sludge storage facilities. at wastewater treatment plants may be necessary. Transport by Pipeline The transport of sludge through pipes can be attractive and economic for sludge as well as for limited amounts of miscellaneous residuals such as screenings, grit, and scum, particularly if the costs of mechanical dewatering can be avoided. Pipelining sludge involves the use of various types of pumps. Losses in pressure from pumping the sludge through pipelines must be estimated for they are not available from standard reference tables. Procedures for calculating changes in elevation and velocity are the same as for water, but sludge has greater frictional losses than does water when pumped under the same conditions. 10 Dewatered sludge may be transported by either short or long piplines. Short pipelines (up to 10 miles) will effectively transport sludge dewatered up to 20 percent solids while long pipelines (greater than 10 miles) can handle sludge up to eight percent solids. There are advantages to pumping digested sludge through piplines: it is easier to pump, and septic conditions resulting in sludge thickening, odors, or corrosion do not occur or are less severe than with raw sludge. A drawback to pipelining sludge is that source and terminal points are fixed, resulting in less flexible routes which are then costly to change. Ocean outfalls, i.e. direct pipeline discharge to the sea, are being phased out as they are no longer legal under the federal Clean Water Act. 154 Barge Transport Barge transport of sludge requires two primary conditions: a wastewater treatment plant pro,ximate to a suitable waterway with necessary shipping and receiving ports, and pumpable sludge. The amount of waterway traffic which may affect transit time is also an important consideration. Barges are of two types: towed and self-propelled. Generally only large operations can afford the latter type. Therefore, contracts must be made with tugboat firms to move the powerless barges. In addition to the design and operation of the vessel itself , the following must be considered: pumps, piping, and docking facilities as well as any sludge storage facilities necessary. Barge transport is generally not cost effective for small' to 'medium size operations (less than 2,000 wet tons of sludge per year) because they do not generate a sufficient amount of sludge. However, coastal municipalities in New York and New Jersey combine sludge volumes through interfacility pumping to a transfer station, or use a common hauler which makes a series of pick-ups along the disposal route. By these methods, plants generating relatively small volumes of sludge may achieve lower individual transport costs through a collective economy of scale. Rail Transport Railroads are not commonly used to transport sludge in the United States. Although railroads have the advantage of established rights-of-way, lower energy cost per unit volume hauled over long distances, and equipment that can be leased, they suffer the same disadvantage as do pipelines: fixed endpoints and inflexible routes. When rail is used to transport sludge, terminal facilities are required for loading and unloading sludge to and from the rail cars. Cost Considerations.for-.All Methods Costs for truck, rail and barge transport include building, operating and maintaining equipment and facilities, travel distances, transit time, and vehicle size and efficiency. Costs will also include expenses involved in intermediate (mode-to-mode) transfers, such as truck to truck as well as intermodal transfers such as truck to rail. Transportation costs may not be easily generalized because costs are plant specific and are not directly transferable to other plant situations. 155 Each mode of sludge transport has its comparative least cost range under specific conditions of variables distance and volume. For example, when transporting liquid sludge (not d@watered): � Trucking is the least expensive way to haul sludge one way, for a distance of 20 miles or less for volumes less than 10 to 15 million gallons per year. � Pipeline is the least expensive way to.transport sludge for volumes greater than 30 to 70 million gallons but becomes too capital intensive for volumes less than 10 million gallons. � Rail and barge modes are comparable in cost for volumes between seven million and 700 million gallons over long haul distances (greater than 10 miles). However, barging becomes more economical than rail for short to medium distances and for volumes greater than 30 million gallons per year. Transfer Stations If wastewater treatment plants are of small to medium size it may be cost effective for the counties or municipalities involved to consider a joint transfer station from which larger quantities of accumulated sludge may be more cheaply transported to a final destination. Ideally, a transfer station should be equidistant to all points of sludge generation so that the c.osts of wear and tear of equipment and total employee hours will be equal for all participating plants. Because of limited site availability, however, establishing minimum transport distances for each plant in the transfer network may not be possible. Depending on the percent solids concentration of the sludge from participating plants, various types of loading and unloading equipment may be necessary to transfer sludge at transfer stations. Environmental Impacts of Transportation Environmental impacts from transportation include spills or leaks during transfer or transport operations, impact on pavements from trucks and possibly odors from carrying sludge in open vehicles, although it is possible to cover open trucks once loaded. 156 COMPARISON OF COSTS FOR SLUDGE MANAGEMENT ALTERNATIVES The costs of impfementing the f ive sludge management alternatives considered in this study are displayed in Table 42. The cost data for land application, composting, and incineration alternatives were developed using "Handbook - Estimating Sludge Management Costs", EPA/625/6-86/010, October 1985. Detailed cost calculations for these three alternatives are shown in Appendix E. The costs for ocean disposal were derived from data provided by the Wes tchester County Department of Environmental Facilities based on the most recent contract bid price. As the cost of ocean disposal is based on a fixed price per unit, it includes both the capital cost and the operation and maintenance cost for appoximately 35 dry tons per day. The landfill costs were calculated by EFC; details are included in Appendix E. These costs are based on two hypothetical co-disposal sites of 100 acres and 880 acres for municipal solid waste combined with sludge and septage. Table 42 and Table 43 show base capital cost and annual operation and maintenance (O&M) costs for a 10 dry tons per day (3,650 tons per year) and a 30 dry tons per day (10,950 tons per year) for the land application, composting and incineration alternatives. Cos ts in Table 42 are given in thousands of dollars.- Costs in Table 43 are in dolars per dry ton. All costs are based on the fourth quarter 1984, Engineering News Record Construction Cost Index of 4,171. To derive capital cost per ton, a amortization period of ten years was used at 12 percent interest. 157 TABLE 42 COSTS TO IMPLEMENT SLUDGE MANAGEMENT OPTIONS ($1,000) LAND APPLICATION COMP09TING INCINERATION OCEAN LANDFILL MULTIPLE HEARTH FLUIDIZED BED DISPOSAL 11 TPD 100 TPD 10 TPD 30 TPD_ 10 TPD 30 TPD 10 TPD 30 TPD 10 TPD 30 TPD (35 TPD) 100 ACRES 880 ACRES .BASE CAPITAL ($) 650 1,000 4,400 3,300 5,300 1,600 2,350 138 225 138 ANNUAL 0 & M M 160 470 400 950 550 1,400 800 .1,160 TPD tons per day TABLE 43 00 COST PER TON FOR SLUDGE MANAGEMENT OPTIONS WTON) LAND APPLICATION COMPOSTING INCINERATION OCEAN LANDFILL MULTIPLE HEARTH FLUIDIZED BED DISPOSAL 11 TPD 100 TPD 10 TPD 30 TPD 10 TPD 30 TPD 10 TPD 30 TPD 10 TPD 30 TPD (35 TPD) 100 ACRES 880 ACRES 0 & M M 44 43 110 87 151 128 219 100 109 56 38 CAPITAL AND 75 75 168 158 311 214 284 138 0 & M ($) LAND AREA 5 ACRES/ 15 ACRES/ 5 ACRES 13 ACRES 100 ACRES 880 ACRES REQUIRED DAY DAY TPD = tons per day tb OTHER WASTESTREAMS GENERATED DURING THE SEWAGE TREATMENT PROCESS Several wastestreams are generated during the sewage treatment process which should be considered in any sludge management plan. Grit Inorganic particles similar to sand enter the collection system through manholes, storm water connections, infiltration, and other sources. Quantities of grit vary substantially. The integrity of the sewer collection system is key in eliminating grit. A leaky collection system will carry large amounts of grit into the system with storm or ground- water. The type, method of operation, and efficiency of the grit removal system installed at a particular STP will also affect the quantities of grit needing disposal. Floatable Solids These include grease, scum, plastic and rubber goods which, because of their resistance to treatment by conventional treatment processes are removed by skimming devices and separated for special handling. While the quantities of floatable solids are fairly stable for domestic waste, commercial and industrial discharges can substantially affect the quantities. Screenings Bar screens are included as preliminary treatment at most STPs. Materials captured on screens are generally removed and separated for special handling. The type, size, and frequency of cleaning of bar screens affects the quantity of screenings generated. Industrial Wastes In many cases, industries either do not discharge their wastes to municipal collection systems or their wastes are pretreated prior to discharge into the municipal system. The quality and quantity of such wastes will vary with the type of waste generated and the type of pretreatment process emp loyed. Industrial and commercial wastes were specifically excluded from thi s study. However, EFC recommends that any future design effort toward a regional facility consider such wastes. A waste management program which ignores industrial and commercial wastes may severely hamper business development in the region. Tab le 44 estimates the quantities of grit, floatable solids, and screenings generated by each county. The following factors were applied to arrive at these estimates: grit 47 pounds per million gallons per day (mgd) floatable solids 7 pounds per million gallons per day (mgd) screenings 6.5 pounds per million gallons per day (mgd) 159 TABLE 44 PROJECTED QUANTITIES OF OTHER WASTESTREAMS FROM THE SEWAGE TREATMENT PROCESS FLOW GREASE GRIT SCREENING TOTAL County (mgd) (tons/year) (tons/year) (tons/year) (tons/year) DUTCHESS 14.3 18.3 123.0 17.0 158.3 ORANGE 22.4 28.6 192.0 26.6 247.2 PUTNAM 1.6 2.0 13.7 1.9 17.6 ROCKLAND 30.9 39.5 265.0 36.7 341.2 SULLIVAN 7.3 9.3 62.6 8.7 .80.6 ULSTER 9.0 11.5 77.2 10.7 99.4 WESCHESTER 125.1 160.0 1,073.0 .148.4 1,381.4 210.6 269.2 1,806.5 250.0 2,325.7 160 Due to the high variability in the quantities of these materials, as discussed previously, engineering guidelines give wide ranges for estimating the quantities. one source* gives a grit quantity range of 0.33 cubic feet to 27 cubic feet per million gallons. The factors for industrial wastes were supplied by Mr. Charles DeFazio, P.E. , Superintendent of Operations, Albany County Sewer District. They reflect actual quantities received over several years. Albany County experimented with incinerating these materials using a multiple hearth but experienced difficulties. They current-ly landfill all grit, screenings, and float.able solids. As the quantity and quality of industrial waste is inconsistent, they cannot be estimated. Industrial wastes would have to be studied by each county and the applicability of disposal options to the.specific wastestreams assessed. wastewater Systems Engineering, Dr. H.W. Parker, P.E., Prentice-Hall, Inc., Englewood Cliffs, New Jersey, 1975. 161 REVIEW OF PREVIOUS COUNTY ENGINEERING REPORTS RECOMMENDING TECHNICAL ALTER14ATIVES Introduction To become familiar with previously recommended solutions for sludge management problems in the region, EFC staff reviewed past engineering reports prepared for the seven counties. A description of the contents of these reports is given in this section. Generally, the reports presented many cost eff ective and evironmentally sound strategies for sludge management in the region. However, these strategies were not implemented. As a result, sludge management in the region is uncoordinated and many municipalities are unable to manage their wastes in a coordinated, cost effective and environmentally sound manner. DUTCHESS "Engineer's Report for the Identification and Resolution of Abnormally High Copper Concentration in Sludge Generated by the Fleetwood and Roc kingham. Sewage Treatment Plants," Morris and Andros, April 1985 (revised May and October 1985). The Fleetwood and Rockingham sewage treatment plants, along with several other STPs in the region, have recorded high levels of copper in their sludge. These high copper sludges significantly reduce the options available for their disposal. Sludges containing metals in excess of regulatory limits are restricted from being used for composting or land app lication. Future restrictions based on metal content which would affect sludge intended for disposal by these methods, as well as by ocean disposal and incineration may be implemented by NYSDEC or USEPA, leaving only landfilling as a possibility. As the two treatment plants addressed in the study use land disposal to their economic advantage, it was imperative to find the cause of the high copper concentrations and plot a course of action to reduce these concentrations to acceptable levels. The source of the copper'was determined to be the corrosive nature of the potable water supply which caused the release of copper from household plumbing systems into the domestic water. When this water is discharged to the STP as wastewater, the density of the copper causes it to settle out and become incorporated with the sludge. The report recommended adding a chemical (sodium hexametaphosphate) to coat the copper piping and prevent the removal of copper by the corrosive water supply. 162 EFC discussed this program with representatives from the consulting firm. The solution is being monitored to determine its success and potential for application at other facilities in the region. ."Dutchess County Resource Recovery Project," Henningson, Durham, and Richardson, September 1981. Complete copies of this report were not made available to EFC, but only sections relevant to sludge disposal. The "Phase I Final Report" section discusses problems encountered in the process of obtaining a permit to -co-dispose sewage sludge with municipal solid waste. It states, "as a result of these potential regulatory problems, it does not seem advisable to combine sludge disposal with solid waste disposal at this time." Additional considerations relevant to co-disposal are addressed in the "Final Environmental Impact Statement" section. Of major interest here is that only small increases in furnace. size and space for co-disposal steam piping would be required to accommodate co-disposal, and that "...sludge from all of the County's major sewage treatment plants, including the proposed Tri-Municipal plant, would only add about 4% to the total load on a resource recovery project." It was also pointed out that "co-disposal will increase the cost of a resource recovery project." However, this increased cost may be less than the cost for full implementation of a separate sludge management program. ORANGE "Report: Alternate Sludge Treatment and Disposal for Orange County Sever District No. l," Charles R. Velzey Associates, October 1974. The drastic increase in fuel prices in 1973-74 caused the Orange County Sewer District (OCSD) to reconsider plans to modify the STP by installing a fluidized bed incinerator. This report considered a number of alternatives for sludge disposal in light of the revised economics associated with incineration: aerobic digestion e heat treatment anaerobic digestion o dewatering methods o chemical oxidation o land disposal (composting, 'D high lime dosage e landfilling, agricultural use) The report recommended modifing the plant to incorporate a high lime dosage sys tem, dewatering the sludge by centrifuge, and using the dewatered sludge as top cover for the landfill to promote growth of the required vegetative cover crop. The OCSD #1 plant was subsequently modified to include a lime stabilization process. The stabilized sludge continues to be used as mix, co-disposed with the refuse, rather than used as a top cover soil amendment to promote the growth of vegetation as the report recommended. Orange County Health Department officials explained that NYSDEC's policy of not locating landfills over aquifers has restricted lateral expansion of the landfill and limited the amount of top cover available for @sludge application. 163 Orange County/SCA Services - Sludge disposal project, August 10, 1976. This project planned to apply to land 10 million gallons of sludge and septage per year generated in Orange County. Apparently this was believed to be the total generated in the county at that time. A four million gallon lagoon was planned to store sludge and septage during the times of year when the material could not be applied to land. The project appeared to be well thought out and technically sound with some exceptions that may reflect a lack of experience. Orange County officials reported that the project was never implemented due to an apparent conflict between a private contractor and the use of public land for the project site. The concept of the project is technica.lly sound and would be appropriate at this time provided land application rates are consistent with the latest regulatory standards, the odor control approach was revised, and a contractor was selected who could demonstrate successful implementation of a large-scale land application project. "Refuse/Sludge: The 'sensible approach to co-disposal of domestic refuse and municipal wastewater treatment plant sludge," Wehran Enginering, P.C. and Egan & Sons, Inc. (1980). This report describes a demonstration project conducted at the Orange County Landfill that co-composted municipal refuse and sewage sludge from the Middletown STP. This was a somewhat innovative project six years ago; Today, co-composting projects are still in the developmental stages. The report discusses the use of a specially designed rotary drum to mix refuse and sludge and separate unwanted materials. While the report indicated that the demonstration project was successful, the composting process has undergone substantial development during the intervening years and techniques suggested could be considered to be outmoded. The report is an excellent one, however, and demonstrates that such a project could succeed in the region if properly implemented. "Alternative Action Study: Orange County IF Expansion" O'Brien & Gere, August 1985. Orange County initiated this study at NYSDEC's request, because of agency concerns about the potential contamination of the principal groundwater aquifer underlying the Orange County Landfill (OCLF). , Current NYSDEC policy is to discourage expansion or construction of landfills over principal aquifers. In addressing the groundwater contamination question, the report concluded that "the natural silt and clay deposits present at the site coupled with an enhanced engineering design of the expansion, including groundwater control and a double liner system with leachate collection, should provide reasonable protection of the principle aquifer located beneath the landfill site and allow the site to be operated in accordance with regulatory requirements." Alternatives to expanding the existing OCLF were: development of a new regional landfill, energy recovery, materials recovery, and composting. 164 The study concluded that expansion of the existing 0GLF was the preferred alternative as this approach "offered the greatest accessibility, lowest hau ling cost, and lowest development cost" and that "energy recovery, which offered the only technically feasible alternative that could potentially effect a significant reduction in landfill requirements, would likely double the cost of waste disposal in the County." Currently, Wehran Engineering is preparing a draft environmental impact statement on the landfill expansion recommended by this report. Public hearings are anticipated. PUTNAM I'Septage and Sludge Treatment and Disposal Study for Putnam County, New York," Malcolm Pirnie, June 1981. This study focused mainly on the problems of septage disposal in Putnam. Individual on-site septage systems are used by approximately 87 percent of the county population. These systems generate approximately 4.7 million gallons (588 dry tons at three percent solids) of septage annually. At the time of the study, there was one site available for septage disposal with a capacity of 300,000 gallons, indicating that over four million gallons of septage were being sent of out of the county for disposal or disposed in the county by unregulated methods. The report specifically recommended expanding and modifying the Carmel #2 STP so it could accept li qui d sludge and septage in a separate process train. After appropriate treatment, this sludge would be dewatered for disposal at a county landfill. In Malcolm Pirnie's opinion, this would resolve the septage disposal problem. At the time of this writing, the general approach of using a n STP to receive liquid septage will most likely be implementated in Putnam. ROCKLAND "Rockland County Sever District No. I Sludge Management Report" Metcalf & Eddy Inc./Engineers, January 1980. Thi s voluminous report is divided into several parts, each dealing with the relevant aspects of sludge management from evaluation of conceptual alter.natives to siting an engineered facility. "Part I - Technical Analysis" reviewed all available disposal alternatives and their application to a regional (county) solution to sludge management. This portion of the report concluded by recommending an aerated static pile composting facility and seasonal land application of sludge to farmland solely for the use of Rockland County Sewer District No. I (RCSD#l) and suggesting that the other county sewer districts seek individual solutions. The rationale for individual approaches appeared to be the one year's lead time required to develop a multi-district solution. Due to this anticipated delay, "the additional interest during construction partially erodes any cost savings offered by a joint facility." An item worth noting is found on page 4-6: .165 The analysis of sludge presently produced at the Rockland County plants indicates that the sludge quality is typical of largely domestic wastes. Concentrations of heavy metals and toxic organics are low, making the sludges suitable for any sludge management option, including land application. Pretreatment for the purpose of improving sludge handling appears to be unnecessary. Th is statement appears to be contradictory to the finding in this EFC study that high levels of copper in the sludge will restrict its use for land application or composting. Part II of the consultant's report discusses in detail the existing natural and man-made environment, and the land application and composting alternat'ives. Three potential compost sites, all in Clarkstown, were identified. No sites with potential for land application were identified within Rockland County. Stewart Airport in Orange County was identified as a suitable site for land application., The report recomended implementing a composting program at the Clarkstown 40 Landfill and developing a land application program at Stewart Airport and the Merion Blue Grass Sod Farm. "Value Engineering Study Report, Study Mo. 1, Rockland County Water Pol lution Control Plant,," Camp, Dresser & McKee, Inc. and Smith, Hinchman & Grylls Associates, Inc., May-June, 1981. This study recommended relocating the planned composting facility from the Clarkstown Landfill to the RCSD#l treatment plant site. With additional recommendations for changes in the plant layout, a $4.8 million cost savings was projected. The project would cost an estimated $70 million. "Rockland County Sewer District Mo. 1 Sludge Management Report Draft Environmental Impact Statement (SEQR) Environmental Information Document (NEPA)," Metcalf & Eddy, Inc., Engineers,, June 1982. This report is an environmental assessment of the relocation of the composting site from the Clarkstown Landfill to the treatment plant site as recommended by the CDM value engineering study. The conclusion was that, despite some short term impacts, the treatment plant site was environmentally and economically suitable for the relocation of the composting facility. "Public Hearing for the Relocation of Rockland County Sewer District No. I Proposed Composting Facility - Responsiveness Summary," Metcalf Eddy,Inc., Engineers, August 11, 1982. This was prepared in response to comments received at public hearings. It recommended that the composting facility not be relocated to the treatment plant site, as suggested by the value engineering study, because a nursing 166 home was located within 1500 feet of the proposed facility and the public strongly opposed it. It further recommended that "alternative sites in the vicinity of the Clarkstown Landfill be reconsidered for suitability and that' the most cost-effective parcel in that location be selected as the recommended site" (p. 2). "Rockland County Sewer District No. 1 on Geotechnical Site Feasibility Investigation for Rockland County Compost Facility, Clarkstown, N.Y.," Metcalf & Eddy, Inc./Engineers, July 1983. Thi s report essentially reevaluated sites in the vicinity of the Clarkstown Landfill which were discarded in favor of the using the treatment plant. A sit e adjacent to the landfill was chosen. This site, basically, was chosen as the preferred site in the January 1980 report. SULLIVAN "Sullivan County Comprehensive Solid Waste Stu.dy," Wm. R. Troutman Associates, Professional Engineers, June 1974. Just one page was devoted to the question of disposal of sludge from municipal treatment plants. As the date of this report predated concerns and strict regulatory constraints relative to sludge disposal, this is not surprising. The closing paragraph of section 5.9 states: After the sludge has been adequately treated and dried it may be safely disposed of by incineration, landfill or used as fertilizer on farm land. Because the q u a n t ities of residue are small and scattered throughout the County, the present methods of disposal are felt to be satisfactory. No other, more recent report has been prepared for Sullivan County. ULSTER "Solid Waste Management Study for Ulster County," Barton & Loguidice P.C., February 1985. This report concentrated on the refuse portion of the solid waste stream with minimum discussion of sludge and septage. However, the report makes specific recommendations summarized here: 1. Septage disposal by lagooning, presently the option for two-thirds of Uls ter County's septage, should be phased out in favor of disposing of this material at STPs. The report cites available capacity at STPs wit hin the county and warns against potential overloads and upsets due to improper handling of septage at sewage treatment plants. 2. Sludge disposal at landfills or by composting is felt to be more appropriate than co-incineration. Wet sludge "may" be landspread where suitable land is available and if it has-'leen stabilized. 167 In discussions relevant to sludge and septage disposal, the report points out the problems with present landfills, limited capacity and non-adherance to current regulations, and cites the need for new landfills that will conform to NYSDEC regulations. Potential sites for new landfills, as well as resource recovery facilities and transfer stations, are also discussed. EFC agrees with Barton and Loguidice's first recommendation to dispose of septage at STPs, as long as adequate sludge handling facilities are available at the treatment plants. Adequate facilities could best be provided at selected regional sites which because of economies of scale, would mean lower costs for construction and monitoring equipment. With regard to the second recommendation, EFC believes sludge dewatered to 20 to 25 percent solids contains sufficient Btu content to permit co-incineration. This approach is preferable to landfilling and losing this energy value. Landfilling wet sludge (20 percent solids) contributes significantly to leachate formation and wastes landfill capacity when it could be recycled instead. WESTCHESTER "S1 udge Management Report Westchester County", Havens and Emerson, Ltd., February 1977. This report was prepared for the Westchester County Department of Environmental Facilities (DEF) in response to the USEPA ban on ocean dis posal of sludge scheduled for December 31, 1981. A lawsuit filed by the City of New York against the USEPA challenging this decision has resulted in an extention of permitted ocean disposal until January 1991. The uncertain future of this disposal method prompted the DEF-to commission this report to study the cost effectiveness, environmental impacts and process considerations involved in implementing a sound sludge management program at its seven treatment plants: Ossining, Peekskill, New Rochelle, Mamaroneck, Rye (Blind Brook), Port Chester, and Yonkers. In addition, the consultant reviewed the Interstate Sanitation Commission's (ISC) recommendations for a "Metropolitan Area Sewage Sludge Management Program" for their appliizability to Westchester. Summarizing the methods for sludge management, the report stated: "All methods of sludge disposal were reviewed for possible uti lization in Westchestet County. Sanitary landfilling and land application were not found to be practical within the confines of the County. Composting appears to be a viable sludge stabilization method, but acceptable sludge characteristics (particularly heavy metal limitations) and availability of sufficient land are necessary for successful implementation. Multiple hearth incineration was found to be the best method of thermal reduction of sludge alone owing to the lack of experience with pyrolysis. Co-disposal of sludge and solid wastes by incineration is being practiced in Europe. Co-disposal by pyrolysis is being developed here in the United States". 168 0 The report found the sludge disposal plans for New Rochelle, Ossining, Peekskill, and Blind Brook to be cost effective and environmentally sound. It recommended that composting be evaluated for the Peekskill STP. The bulk of the study concentrated on a management program for the Yonker's fac ility, the source of approximately 60 percent of the sludge generated in the county. Nine sludge management alternatives were developed for the Yonkers STP: 1. Grasslands Combined Sludge/Solid Waste Thermal Reduction Plant: Barging and Pumping of Liquid Sludge 2. Grasslands Combined Sludge/Solid Waste Thermal Reduction Plant: Trucking of Filter Cake 3. Grasslands Sludge Thermal Reduction Plant: Barging and Pumping of Liquid Sludge 4. Grasslands Sludge Thermal Reduction Plant: Trucking of Filter Cake 5. North Central Yonkers Thermal Reduction Plant: Pumping of Liquid Sludge 6. North Central Yonkers Thermal Reduction Plant: Trucking of Filter Cake 7. Croton Point Thermal Reduction Plant 8. Joint Westchester-Rockland Thermal Reduction Plant 9. Metropolitan Regional Pyrolysis Plant The conclusions and recommendations of the report are presented here: Conclusions 1. Land application and sanitary landfilling in Westchester County are not feasible because of the unavailability of sufficient suitable land area, high population density, terrain characteristics, presence of wetlands and flood-prone areas, and the socioeconomic effects of removing large tracts of land from community tax rolls. 2. Recent developments have demonstrAted that composting is a viable sludge stabilization method. In Westchester County, however, composting would be limited by heavy metals in the sludge, land requirements and expected difficulties in the development of potential markets. 3. There is insufficient experience at present to design a pyrolysis plant for sludge alone. 4. For Yonkers, multiple hearth incineration is the best proven method of thermal reduction. 16.9 5. Disposal as planned for Ossining (incineration), Peekskill (dewater and landfill), New Rochelle (incineration), Mamaroneck (pump to New Rochelle), Blind Brook (Rye)(pumped to Port Chester), and Port Chester (incineration) is considered to be the most feasible means' of sludge disposal for the present, considering cost effectiveness, environmental impact and time required for plan implementation. 6. The addition of composting facilities at Peekskill as an alternative to landfill disposal of sludge cake should be evaluated. I. a 7. In the future, consideration should be given to combining sludge disposal for the four plants on Long Island Sound at a single location, to composting some or all of the sludge, and to disposal at the facility to be built for disposal of sludge from Yonkers. 8. Plans developed for Yonkers should consider ease of future expansion to accommodate sludge from other plants. 9. Heavy metals in Yonkers' sludge indicate that thermal reduction is the only viable method for its disposal at this time. 10. Site limitations and environmental factors prohibit the development of thermal reduction facilities at the Yonkers Joint Treatment Plant. 11. Facilities for thermal reduction of sludge at Grasslands will cost less if combined with solid waste disposal. 12. Two possibilities for participation by Westchester County in the ISC recommended Metropolitan Sludge Mangement Program are for disposal of sludge at proposed regional pyrolysis plants to be located at Hunts Point in the Bronx and at Port Newark. However, there are no ind ications at present as to when or how ICS' recommended program will progress. 13. Based on cost effectiveness, Plan 8 (joint Westchester-Rockland The rmal Reduction Plant) is the most desirable alternative, but may be difficult to implement. 14. Bas ed on environmental impact, Plan 9 (Metropolitan Regional Pyrolysis Plant), Plan 1 (Grasslands Sludge/Solid Waste Thermal Reduction Facility - Barging), and Plan 5 are preferable. 15. Based on process considerati ons, the most desirable alternatives are presented by Plan 6 and Plan 2 (Grasslands Sludge Thermal Reduction Facility - Trucking). 16. At some future date., after secondary treatment facilities at Yonkers go into operation and source control of heavy metals is put into effect, sludge may become suitable for composting. 170 Recommendations I Construct sludge disposal facilities for the County wastewater treatment plants at Ossining, Peekskill, New Rochelle, Mamaroneck, Blind Brook (Rye),and Port Chester as planned, with the possible addition of composting facilities at Peekskill. 2. Initiate discussions with Rockland County to explore the possibility of constructing a regional sludge disposal facility on the west bank of the Hudson River to serve the needs of both counties. 3. Should negotiations with Rockland County be unsuccessful (item 2 above), incorporate sludge disposal with plans for thermal. reduction of solid waste at Grasslands. 4. As an alternative, consider sludge disposal at a Metropolitan Regional Pyrolysis Plant if and when plans for these facilties develop. 5. Determine the possibility of receiving federal and state aid for any of the management plans. 6. Amend the County's wastewater treatment plan adopted with the 1968 Comprehensive Study when a sludge management program is decided. In EFC's opinion, the alternatives recommended by this report appear to have con'siderable merit. However, none of the recommendations were ever imp lemented. Westchester DEF officials have indicated that the suggestions wer e virtually ignored because of the availability of ocean disposal, which is low technology and low cost and avoids the sociopolitical problems of siting a land based alternative. DEF officials futher indicated that Westchester County would not seriously consider any alternative to ocean disposal as long as this option was not prohibited. At the time of this report, it appears that ocean disposal will be available to the County for at least the next five years. As much as 10 years could elapse by the time studies are completed on the effects of ocean disposal at the 106 mile site. At the end of whatever review period is required, ocean disposal may sti 11 be a viable disposal option. Accordingly, Westchester County may not seriously consider other options as long as ocean disposal is available. 171 SECTION 4. PRESENT REGULATIONS AND REGULATORY TRENDS RELATED TO SLUDGE MANAGE14ENT This section summarizes existing regulations pertaining to sludge management activities and presents some insight, based on conversations with state and federal officials, on what regulatory policy might be in the future. The reader should consult state and federal regulations for additional information. Land Application Land Application Moratorium Before 1979, a permit was not needed to spread sludge on land. In that year, a Sludge Management Task Force, under the auspices of New York State Department of Environmental Conservation (NYSDEC) recommended that the agency develop regulations to manage land application, which it did in 1980. The NYS Department of Agriculture and Markets maintained that the new rules were not sufficiently stringent and proposed a moratorium on new applications for landspreading on Class I to 4 soils. This represented roughly one-third of the agricultural soils in the state. The moratorium was to last two years, beginning May 5, .1981, after which regulations would be developed. NYSDEC's intention was to incorporate into its regulations USEPA final regulations concerning heavy metals which the federal agency was to develop during this time. The final federal regulations, however, addressed only cadmium and PCBs and were not as strict as NYSDEC's rules which covered seven metals and PCBs. NYSDEC and the Department of Agriculture and Markets issued a draft environmental impact statement on the moratorium in the, fall of 1982, fol lowed by six public hearings. A final impact statement was released in the spring of 1983. In August of that year, NYSDEC Commissioner Henry G. Wil liams issued a decision which ended the moratorium. The Commissioner's decision included guidelines for landspreading sludge. Since 1983, all NYSDEC permits issued for landspreading comply with these guidelines. NYSDEC has no plans at present to incorporate the guidelines into regulations. As with all sludge disposal options, with the exception of ocean disposal, NYSDEC strictly regulates all sludge land application programs. Regulations for land application activities are contained in 6NYCRR Part 360, "Solid Waste Management Facilities" (7/14/85). Policies in these regulations and from other sources are further discussed and interpreted in the publication "Solid Waste Management Facility Guidelines" (5/81) available from NYSDEC. 172 Sludge Composition Sl udge that does not mee t NYSDEC quality requirements may not be applied to land. Attempts to dilute controlled contaminants are not permitted. A sludge generated at a site that does not meet contaminant limits cannot be mixed with "clean" sludge and septage to produce a composite material that meets the regulati.ons. NYSDEC encourages contaminant reduction at the source through an effective pretreatment program or by other means, thereby reducing the total amount of contaminant substances in the environment. Specific contaminants regulated by NYSDEC and their respective limits are delineated in Table 45. Heavy Metals and Toxic Organics These substances are tightly controlled because of potential negative effects on the environment. More specifically, some of these substances demonstrate an ability to inhibit plant growth (phytotoxicity), have shown carcinogenic tendencies in humans, and have potential negative effects on food chain animals. Pathogens Pathogens are organisms which cause disease in humans. As sewage sludge potentially contains many types and numbers of pathogens, the regulations restrict land application to sludges which have been subjected to a ','Process to Significantly Reduce Pathogens" (PSRP). A description of PSRP may be found in Appendix F. Miscellaneous Factors As a first priority, sludge must *be "clean" and stabilized prior to land application. This may require pretreatment or a treatment plant upgrade. Subsequently, several other considerations also apply. These factors may be generally divided into site considerations and management considerations. In addition to the restraining factors discussed here, agricultural or. local laws may present additional impediments. 173 TABLE 45 CONTAMINENTS REGULATED BY NYSDEC Maximum Concentration, ppm* Parameter Dry Weight Basis Merc ury (Hg) 10 Cadmium (Cd) 25 Nickel (Ni) 200 Copper (Cu) 1000 Lead (Pb) 1000 Chromium (Cr) 1000 Zinc (Zn) 2500 Total PCBs 10 ppm parts per million SOURCE: "Solid Waste Management Facility Guidelines; NYSDEC, 5/81, p. 7-1 174 Site Considerations 1. The land application site may not be located in a floodway, defined in New York State regulations (6 NYCRR Part 500) as "the channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than one foot at any point." 2. Land application to agricultural soil groups I to 3 is permissible. However, the cumulative loading limits are more restrictive than on soil groups 4 to 10 (see also "Decision of the Commissioner", Appendix G). Maps indicating soil group classification may be obtained from each county's soil conservation service. 3. The following separation distances from the land application site are prescribed: � property line 50 feet � residence or business (other than the site operator) - 500 feet � potable well or supply - 200 feet � surface water body - 200 feet � drainage swale - 25 feet 4. The following topographic considerations apply: Liquid sludge (less than 20 percent solids) may be applied to slopes equal to or less than eight percent. Dewatered s 1 udge ( 20 percent sol ids or more or liquid sludge injected parallel to the land contour, may be applied to slopes equal to or less than 15 percent. 5. A minimum of two feet of soil between surface and bedrock must be maintained. See Table 46 for further soil considerations. Management Considerations The Part 360 regulations contain certain program management factors: 1. Loading rates (the rates, generally dry tons per acre, at which sludge may be applied) are to 'be based on sludge quantity and quality, site characteristics, and plant nutrient requirements. 2. Sludge application must be carried out in a manner to avoid surface runoff and in accordance with surface and groundwater standards. 175 TABLE 46 Suitability of SOU and Site Characteristics for Sludge Application t e C041 C!iaracteristics Suitability ar d - - Good Fai r Poor @FS e fite Features Slcpe Less than 8%- 8-12%, Greater than 1.2% ..icodinr No Flooding Floods lVs@ than Floods cne in 10 One in ten years :cipth to Bedrock (Fractured) Greater than 3 ft. 2-5 ft - Less than 2 ft. ':@hvsikcz@,-l -"o-U-ProDerties e x tjr e Loam,'silt loam Silty clay loam, Sand, loa=f sand, sandy loam clay er=cability (in hr.) o.6-6.o 0.2-M6 Less than 0.06 Greater than 6.0 depth to seasonal Greater than 2011 -2-20 Less than 12" iC@h water table ---afficabillity (Unified GW,,GP, SW, SP CL, MH OL, OH, PT --oil Class ification) GM, GC, SM, SC, ML "Peference 11) --,mical Soil ProRerties I* n t op 2 0 Greater than 6.3 5.5-6.5 Less than 5.5 a,.-Jon Exche-rige Cap. Greater than 20 10-20 Less than 10 TEC) Meq. 1100g SOURCE: Solid Waste Management'Facility @uid-elines, NYSDEC, 5/81, p-7-1 (7) 176 3. No sludge application is permitted on snow covered or frozen ground or during periods of rainfall. 4. Maximum cadmium (Cd) accumulation that may be added to agricultural soils is five kilograms per hectare (kg/ha) or 4.5 lbs per acre. A limit of three lbs per acre applies to soil groups 1, 2 and 3. Soil background Cd levels are to be determined prior to land application. Annual Cd app lication rates are 1.25 kg/ha until December 31, 1986. After January 1, 1987, annual Cd application rates are not to exceed 0.5 kg/ha. 5. Soil pH is to be maintained at or above 6.5 during periods of application. 6. Sludge must be incorporated into the soil the same day it is applied. 7. Gra zing by animals other than dairy cattle is prohibited for one month af ter sludge. application. Dairy cattle grazing is prohibited for 12 months after sludge application. 8. Public access is prohibited for 12 months after sludge application. 9. Sludge and septage are not to be applied to land currently used for production of food chain crops for direct human consumption nor are such crops to be grown for a period of 18 months following application. 10. Sl udge and septage must be handled separately and not mixed, otherwise the more stringent sludge restrictions will apply to the mixture. 11. A s ludge stabilized by chlorine oxidation (a stabiliation process that uses high dosages of chlorine) is not suitable for land application. 12. Good soil conservation practices should be used. 13. Storage requirements must be observed. Methods of Operation The NYSDEC Guidelines define three categories or levels of operation based on application rates: Category 1: light loadings of 1 to 3 dry tons per acre per year. Groundwater monitoring and subsurface exploration requirements do not apply to operations in this category. Category 2: heavier application rates calculated to meet the nitrogen requirements of crops. Application rates here are on the order of five to 12 dry tons per acre per year. Category 2 projects require an engineering report and an environmental impact statement. Category 3: relatively heavy loadings (up to 50 dry tons per acre per .year) to reclaim land (landfills, strip mined land, gravel pits, for example.). 177 According to NYSDEC, application of the regulations to Category I and 2 projects is virtually indentical. A Category 3 project has never been approved, and probably would not be unless it could be demonstrated that the leachate generated would not contravene groundwater standards (see 6 NYCRR Part 36,0.8 (a) M). In general, sludge applications exceeding the nitrogen needs of the crop grown will not be approved._ Land Application Program Approval A NYSDEC Part 360 permit must be obtained prior to commencing a land application program. Application for this permit is initiated in the following manner: 1. Engineering plans and reports must be submitted, including: a. Location of the disposal sites on USGS topographical maps (1:24,000). b. Topographical map of the disposal area (200 feet/inch, two feet contour lines). C. Other required information: Location of surface water, wetlandg and the 100 year flood elevation Location of the groundwater table as determined using wells or test pits Soil survey mapping units Surface drainage patterns Location of potable well(s) or supply(ies) within 2,000 feet of the site Location of residences or businesses within 2,000 feet of the site Location of access and approach roads Location of on-site roads Location of property boundaries Location of fencing Direction of prevailing winds Location of drainage swale(s) 178 Location of vegetative cover, large trees, brush, pasture and.structures For Category 3 projects, show location of proposed monitoring wells, surface water sampling stations and soil sampling sites For all sites, on-site soil sampling data to yield background levels of metals'and PCBs 2. Prior to implementating a land application project, a six to 12 month monitoring program of sludge quality is desirable. This requires at least two, or preferably three, samples at a small plant (less than I million gallons per day) and up to six samples from a large plant (greater than 5 million gallons per day). If any substance exceeds limits, an identification and abatement program similar to an industrial pretreatment program should be initiated. In any case, the sludge must meet the quality guidelines set forth in the regulations. Storage Regulations NYSDEC regulates sludge storage facilities under 6NYCRR Part 360 "Surface. Impoundments" and under the "Solid Waste Facility Management Guidelines" Section 7 (g). The following is a summary of these regulations: Storage lagoons must be constructed to hold wastes that cannot be placed on land during certain periods of the year. (A lagoon is a shallow basin formed by a depression in the earth). Storage can also be in concrete or steel tanks. If located at sewage treatment plants (STP) storage facilities are exempt from Part 360. If not at the STP, a leak detection or groundwater monitoring system is reqi'ured. A distance of at least 500 feet must be maintained between the lagoon and the nearest non-owner residence or place of public assembly. At least two lagoons of six months storage capacity are required (one year is desirable). Lagoons must be two to six feet deep. Lagoons must maintain a minimum of two feet of freeboard (the distance from the liquid's surface to the top of the lagoon). Lagoons must be constructed above the 100 year flood level. The bottom of the lagoon must be a minimum of five feet above the seasonal high groundwater elevation. 179 A natural or artific@ al membrane must be constructed to provide hydraulic conductivity to 10 centimeters (cm) per second or less, not to be damaged during cleaning. (Hydraulic conductivity is the ability of a substance to conduct or permit the passage of liquids, similar to permeability). The lagoon must be properly fenced. Appropriate insect control measures must be practiced. The lagoon is to be emptied and cleaned at least every six months. Drainage to surface waters is subject to Article 17 of the Environmental Conservation Law. If the berm (curb or wall, usually earthen) elevation is higher than the surrounding ground elevation, a spill prevention control and countermeasure plan is to be.submitted for approval. The lagoon must not violate ambient air quality standards and must minimize objectionable odors at the property line. Groundwater monitoring or a leak detection system will be required. Landfill Present Situtation Currently, the 20 percent solids concentration and the stabilization requirements in the solid waste regulations are being examined by NYSDEC as .it reviews currently operating landfills. Increased enforcement of criteria will only exacerbate operational deficiencies at present sites. Where dewatering capability exists at sewage treatment plants, and the sol ids concentrations approach 20 percent, NYSDEC might conditionally allow landf illing at existing sites. Where an STP has been constructed without the inclusion of an approved stabiliza.tion method and no other feasible disposal alternative is available, disposal of sludge is presently being tolerated. Note that this is not true for land application; criteria must be followed for this option. Several factors could alter this situation: 1. Change in NYSDEC policy or regulations 2. Plans for STP facility upgrade by the municipalities could result in the inclusion of an approved stabilization and dewatering process before NYSDEC will give approval 3. The future availability of a feasible disposal alternative. 180 Most municipal or private landfills currently operating within the region do not have permits. As these facilities were constructed prior to the promulgation of Part 360, they lack significant environmental safeguards required by the regulations. Present NYSDEC policy requires that one of two conditions be satisfied for any landfill to continue operating after July 1, 1986: 1. The facility must be in complete compliance with Part 360 and receive a valid permit 2. The facility must be operating under a NYSDEC consent order with a schedule of compliance to achieve full permit status. Fac ilities which do not meet either of the above conditions will be closed. NYSDEC's current regulatory direction is obviously toward full compliance in a situation where, for most regional landfill operations, compliance means a substantial economic and engineering commitment. Future Policy NYSDEC's present policy prohibits new and horizontal expansions of landfills over primary and principal aquifers identified in the Upstate Groundwater Management Plan. The agency is strongly encouraging applicants to do a hydrogeologic assessment before beginning any landfill project. NYSDEC is moving toward requiring a double liner and monitoring, collection and treatment facilities for all landfills, similar to the requirements for secure landburial facilities. The agency presently reviews each landfill A application individually and grants permits on a case-by-case basis. It is, however, more difficult now than ever to qualify for a permit. Composting Present Situation Compost use in New York State is strictly regulated by the New York State Department of Environmental Conservation through 6NYCRR Part 360, "Solid Waste Management Facilities". Basically, the regulations control the production of compost based on the final useage of the material. There are two categories of useage: Case I - compost is made available to the general public and the final user receives the compost at the STP or from an intermediate distributor. Case II compost is intended for use on dedicated or publically-owned land. 181 NYSDEC requires a Part 360 permit to operate a composting facility in New York State. The permit conditions for Case I are: 1. The composting process must be operated and maintained so it meets the req uirements for a process to further reduce pathogens (PFRP) as defined by 40CFR Part 257 (see Appendix F). 2. The final composted sewage sludge must be monitored immediately following the process to further reduce pathogens. @The sampling should be done as follows: Production Compost to be Number of Grab Distributed Samples to Frequency of Parameter (dry tons/day) Make Composite Analysis Heavy Metals <1 I per month 2 per year (Cd, Total 1 to 10 1 per month 1 per month Cr, Cu, Hg, >10 3 per week I per week Ni, Pb, and Zn)* PCBs <1 I per year I per year I to 10 1 per month 2 per year >10 I per month 2 per year > = greater than < = less than Cd - Cadmium Cr - Chromium Cu - Copper Hg - Mercury Ni - Nickel Pb - Lead Zn - Zinc 3. The facilities must maintain records on the quality data resulting from the above analyses and on operational data (including time, temperature, and volatile solids reduction data) on the composting operation. 4. The maximum contaminant concentration of the composted sewage sludge must not exceed the following levels on a dry weight basis: cadmium 10 mg/kg* lead 250 mg/kg PCBs I mg/kg Chromium, Copper, Mercury, Nickel and Zinc as shown in Table 45. mg/kg = milligrams/kilogram 182 5. The following information must be made available to the final user either through labeling, through signs posted at the site where composted sl udge is made available to the general public, or by-leaflets intended for distribution to the final user: a. The material is a composted sewage sludge composted by a process to further reduce pathogens (PFRP) as described in USEPA regulations 40 CFR Part 257. b. The compost should not be used on home gardens, but is recommended for lawns or other landscaping uses where the soil will not be used for growing vegetables. In addition to the above, the following conditions should be observed by large compost producers (i.e., more than 300 dry tons of compost per year) under Case I: a. The permittee must keep records of deliveries to final users of more than 100 dry tons of compost per year. Records must include the name of the final user, the site to which the delivery was made and the address of the final user. These records must be available for inspection on request. b. The permittee must record the name and address of any party who obtains more than 30 cubic yards of compost at one time from the composting site. These records must be available for inspection on request. The conditions to compost sludge for use under Case 11 include: a. The compost must not be made available to the general public. b. The compost must be used for a specific purpose, including publicly owned lands dedicated to non-agricultural purposes such as a golf course, industrial park, rights-of-way, land reclamation, to establish final vegetative cover on a landfill, or other similar non-agricultural purposes. C. Sludge, to be composted, must be sampled and monitored according to procedures outlined in Section i of the NYSDEC "Solid Waste Management Facilities Guidelines" on land application (Section 7.1). Sludges are considered to be suitable for composting if their pollutant concentrations do not exceed the values shown in Table 45. Other considerations may be required but need not be more restrictive than those specified in Section 7.1 of the Guidelines. These conditions would control composting site separation distances, application practices, application rates and other site monitoring if appropriate. 183 Future Policy Presently, regulations governing composting are not very detailed. NYSDEC is planning revisions which will include more explicit information about requirements for compliance. The agency is especially concerned about requiring procedures to follow the federal Process to Further Reduce Pathogens (Appendix F), to ensure that the sludge does not pose a health hazard. Ocean Disposal Present Situation USEPA presently allows nine municipalities to dispose in the ocean: New York City, Westchester County and Nassau County in New York and six municipalities in New Jersey. They are all disposing under court order. Prior to 1985, ocean dumpers used the 12 mile site in the New York Bight. Last year, USEPA began to move all dumping to the 106 mile site, which exp ires in 1991 (see Section 3, Ocean Dumping for more information). Each of the nine users are on a negotiated phase-out schedule to be completed by December 1987. Westchester began using the 106 mile site for all its dumping in March 1986; Nassau moved 100 percent of its dumping in June, and New York City and New Jersey are on a stepped schedule. There have been no new requests for permits with the exception of Boston, which had its application returned as incomplete. Subsequently Boston has dec ided not to resubmit its application. Boston's original application was for three years--1988 to 1991. The municipality is planning a new secondary treatment plant to be completed in 1996, but USEPA is not aware of any specific reason for the delay in completing the application. Future Policy USEPA has notified all nine ocean dumpers that a permit is now required for use of the 106 mile site. The applicant must, as part of the submission, prove that no other acceptable disposal alternative exists. Should USEPA determine that another option is, in fact, feasible, it will deny the ocean dumping permit. This may force the present users to adopt other waste 41 management alternatives more quickly than anticipated. USEPA is conducting studies at the 106 mile site to monitor the environmental effects of disposal there. The agency has no firm policy as yet for redesignating the 106 mile site in 1991. Most likely, its evaluation will consider the results of the monitoring studies as well as the availability of alternative options to the present users. 184 incineration Present Situation All incinerators must comply with federal and state regulations designed to reduce the amount of emissions to the atmosphere. The potential for emissions from an incinerator varies widely, depending on such factors as the characteristics of the sludge, incinerator design, and operating procedures. Some test data is available which indicates that, on the average, stack gas es of uncontrolled sewage sludge incinerators contain about 45 pounds of particulates per ton of sludge burned. Gaseous pollutants that could be released into the atomsphere are sulfur dioxide (So ), nitrogen oxides (NO' ), carbon monoxide (CO),- and hydrochloric acid (HH). Sulfur content in xsludge is relatively low, less than one percent, and much of the sulfur may be in the form of sulfate which originated in the wastewater. Thus, sulfur dioxide is not expected to be a serious problem. Sludge incineration temperatures are generally less than 1500 0F which are too low to form nitrogen oxides of more than 200 parts per million (ppm). Carbon monoxide is not a problem if the incinerator is properly operated. Hydrochloric acid emissions depend principally on the amount of combustible plastics in the sludge. Conventional sewage treatment processes do not remove appreciable quantities of heavy metals or synthetic organics in sludge, although it can destroy most synthetic organics-with adequate- temperature and burning time. Toxic organic chemicals from pesticides or other organic compounds in the sludge may be released during incineration. Data reported by USEPA indicates that pesticides and organic compounds such as aldrin, dieldrin, chlordane, DDD, DDT and PCB were found in randomly selected raw municipal sludges. Federal Regulations USEPA New Source Performance Standards (NSPS), apply to incinerators built or modified after June 11, 1973. Any incinerator which burns wastes consisting of more than 10 percent dry sewage sludge, or sends more than 1000 kilograms (1.12 tons) of sludge to the incinerator per day, is subject to the standard. Existing facilities which are modified in any way that increases the amount of particulate matter emitted also become subject to the NSPS. A facility is considered to have commenced construction on the date that a continuous program of construction starts, or on the date that a contractual agreement, including economic penalties for cancellation, is signed. 185 A device must be installed to measure the amount of sludge sent into the incinerator to within five percent accuracy. Access must also be provided for taking grab samples of the sludge. No provision is made in the existing standard for monitoring either particulate emissions through periodic . stack testing, or stack opacity,(visual measure of particulate emissions from a stack). (See Appendix H and Appendix I for additional information). Federal standards for opacity and discharge of particulates. from new and modified municipal sludge incinerators are: (1) No more than 0.65 grams per kilogram dry sludge input (1.3 pounds per ton dry sludge input); and (2) less than 20 percent opacity are not subject to the opacity standards. The federal emission standard for mercury as a hazardous air pollutant resulting from sludge incineration was established in 1975. It limits mercury emission to a maximum of 0.29 pound per hour, (see Appendix J). State Regulations NYSDEC controls air contaminant emissions from sludge incineration through 6NYCRR Part 212, General Process Emission Sources, (Appendix K). Part 212 regulates contaminant emissions on the basis of an environmental rating which reflects the potential environmental effects of an emission point on its surroundings. The environmental rating A is assigned for toxic pol lutants for which the source emission must be controlled to more than 99 percent. The environmental ratings B or C are generally assigned for nontoxic particulates. The emission limit is 0.05 grains per dry standard cubic foot. 6NYCRR Part 219, Incinerators, or 6NYCRR Part 222, Incinerators - New York City, Nassau and Westchester Counties.must be observed for co- incineration of refuse and sludge in those locations (see Appendix L and Appendix M). Appendix N is the latest NYSDEC Municipal Solid Waste Incineration Revised Draft Operating Requirements dated June 20, 1986. These draft operating requirements would apply to the co-incineration of municipal solid waste and sludge. Emission Characterisitics of Combine,d Sludge and Municipal Refuse Incineration Very little data is available on the particulate emission characterist-ics of co-incineration facilities. On the basis of data which is available, no overall generalizations can be drawn as to the impact that combined burning has on emissions compared to incineration of the wastes separately- However, given the wide variability in both the types of technologies available for co-incineration and the control devices used with these technologies, as well as the differences in the types of wastes burned, it is doubtful that emissions will show similar charcteristics. This topic requires further investigation during the planning of a co-incineration facility. 186 Control Technologies Used While wet scrubbers are normally used on sewage sludge incinerators, a variety of different control systems are currently being used on refuse incinerators. Of the approximately 45 municipal refuse incinerators currently operating in the U.S., about 23 are equipped with electrostatic precipitators (ESP), 15 use wet scrubbers, baghouses are in use at two plants , and the rest are control devices. Each of the three co-incineration facilities expected to be operating in 1985 are equipped with ESPs. Emission Test Data Emissions tests were performed in 1077 on the multiple hearth sludge incinerator located at the Central Contra Costa Sewage Treatment Plant in Cal ifornia. The incinerator was modified to burn prepared municipal refuse and sewage sludge. Provisions were made to operate the unit in either an incineration or pyrolysis mode. Both the relative amounts of refuse derived fuel (RDF) and sewage sludge entering the furnace, as well as the location at which the wastes entered the furnace, were varied during the test program. Particulate emissions were measured at both the inlet and the outlet of the afterburner. Although the incinerator is equipped with a scrubber, no sampling was conducted on the scrubber inlet. The results of these tests are summarized in Table 47. The individual runs have been grouped according to the ratio of refuse to sludge burned during the test. There is no 'apparent difference in the uncontrolled emission rate of incineration as opposed to pyrolysis, although the emissions from pyrolysis are controlled somewhat bett 'er by the afterburner. This is most likely a function of the difference in the average size of the particles leaving the furnace, which were generally larger when it was operated in the pyrolysis mode. No emissions tests were performed on the furnace when it was incinerating sludge alone. Although particulate emissions appear to decline as the ratio of RDF to sludge declines, this trend could also be a function of how the sludge is charged into the incinerator. The uncontrolled rate of particulate release is generally higher when the sludge is charged separately into the top hearth (runs 8C, 8D, 19 H, and 31 P). In the other runs the sludge was first blended with the RDF before it entered the top of the incinerator. Two sets of emission data were obtained for refuse incinerators co-incinerating sludge. The first set is from the Waterbury, Connecticut, fac ility. This incinerator is a batch-fed, mass burning refuse incinerator with a capacity of about 150 tons per day. The sludge was first flash evaporated and then burned in suspension in the secondary combustion chamber. The ratio of refuse to sludge was approximately 3.5:1. Emissions were controlled by a spray baffle scrubber. The Waterbury unit was not tested in accordance with USEPA procedures. 187 TABLE 47 WASTE FEED RATES AND METHOD DURING TESTS 014 CONTRA COSTA MULTIPLV-HEARTM INCINERATOR Waste Feed Point Waste Feed Rate (dry) Run a Top Third RDF Sludge Total Ratio Number Mode Hearth Hearth lb/hr 16/hr lb/h ROF/Sludge 5A I Blended 595 521 1116 1.1 8C I Sludge RDF 2282 213 2495 10.7 8D I Sludge ROF 2282 213 2495 10.7 11E I Blended 438 325 763 1.4 co 1IF I Blended 438 325 763 1.4 co 17G I Sludge/RDF RDF 2046 .295 2341 6.9 19H P Sludge RDF 2762 288 3050 9.6 191 P Sludge RDF 2762 288 3050 9.6 261 P Blended 2502 374 2B76 6.7 ?9N P B lended 1982 510 2492 3.9 31P P Sludge RDF 2563 438 3001 5.9 a I = Incineration; P Pyrolysis SOURCE: "Second Review of Standards of Performance for Sewage Sludge Incinerators". EPA-450/3-84-010, March 1984 A Consumat modular refuse incinerator was tested while coincinerating sewage sludge. The sludge was first dried in an indirect steam dryer to a 20 to 25 percent moisture content. The dried sludge was not mixed with the r efuse, but rather dumped into the hopper on top of the refuse. Approxmately equal portions of sludge and refuse were burned. The incinerator is not equipped with a scrubber. Afterburners are employed to control particulate and odorous emissions. The data from these two tests is displayed in Figures 34 and 35. For the Watebury facility, no difference can be discerned between the controlled particulate emissions when refuse is burned separately in contrast to combined incineration. There is ' however, a noticable increase in the emissions from the Consumat incinerator when dried sludge is burned, over that observed for refuse alone. Regulatory Issues As mentioned earlier, there is currently no New Source Performance Standard (NSPS) that applies explicity to co-incineration. In the few cases where new facilities subject to NSPS have been built, the emission limit has been determined on an ad hoc basis. Table 48 shows the procedure that has been employed in making these determinations. There are a number of inconsistencies in this procedure. First, there exists a discontinuity when an incinerator is burning 50 percent municipal waste and 50 percent sludge. Also, the separate standards are not expressed in the same units; the conversion from a concentration-based to a mass-based standard is not always straightforward. Additional gaps in the coverage of existing regulations are also apparent. For e.xample, neither federal regulations Subpart E nor Subpart 0 addresses ,the applicability of the standard when an incinerator is operated in a pyrolysis mode. In at least one instance, a planned solid waste pyrolysis project was exempted from the NSPS on this basis. The fact that the existing NSPS for refuse incinerators has a minimum size cutoff (50 tons per day), while no cutoff is given for sludge furnaces, raises a number of questions in terms of the equity of the current procedure for applying the Subparts. For example, a large 250 tons per day refuse incinerator burning 75 tons per day of sludge would have to meet a less stringent standard than 45 tons per day incinerator buring five tons per day sludge. F inally, in some instances, it is not clear whether the present contribution of sludge to the total incinerator charge rate is to be calculated on a wet or dry basis. Because of the lack of sufficient emission data, the difference between alternative co-incineration techniques, and the difference between the two standards, it is not possible to resolve these issues in this study. 189 IWOlYsis Mule (uncontrolle(j) Afterbiorner Outlet Wo 4P V AD .9 so Oc 80 1911 191 17G 26L 31P 11F SA 29H lip. Run Himber Summary of Emissions Tests on the Contra Costa Multiple-hearth Incinerator SOURCE: "Second Review of Standards of Performance for Sewaage Incinerators',' EPA-450/3-84-010, March 1984 12.11 ftefisse dnd Sludip 10.0 Q 8.0- > 6.0- V1 .9 to 4.0- U CL 2.0- 2 3 4 5 6 2 3 4 5 6 Waterbury Incinerator Constnuat Incinerator C@ Summary of Particulate Emissions from Two Municipal -Refuse Incinerators. or Sewage SOURCE: "Second Review of Standards of Performance fch 1984 Slu dge Incinerations", EPA-450/3-84-010, Mar TABLE 48 CURRENT BASIS FOR DETERMINING THE APPLICABILITY OF THE NSPS TO INCINERATORS Municipal Incinerator a) Sewage Sludge Refuse Charging Rate Applicable (Percent) (Percent) (tons/day) Subpart 100 0 any rate Subpar-It, 0 51 - 100 0 - 49 > 50 total waste Prorated, O/E b) 0 - 50 50 -.100 > 50 total waste Subpart E 0 100 <50 municipal refuse None I - 99 1 - 99 <50 total wastes, Subpart 0 >1.1 sewage sludge 11 - 99 1 - 89 <50 total wastes, Subpart 0 sewage sludge 0 - 10 90 - 100 <50 total wastes, None 1.1.1 sewage sludge a) Subpart 0: 1.3 lb particulate/dry ton sludge input; Subpart E: 0.08 grains/dry standard cubic foot flue gas b) OSSE determination (E-7), May 17, 1976, allows a prorated standard based on the percentage of each waste consumed. SOURCE: "Second Review of Standards of Performance for Sewage Sludge Incinerators", EPA-450/3-84-010, March 1984 192 NSPS Applied to Former, Existing, and Planned Co-incineration Facilities Various determinations have been made in the past as to which NSPS should apply to co-incineration. Of'the facilities that were formerly co-incinerating, only the Holyoke, Massachusetts, and Duluth, Minnesota inc inerators were subject to the NSPS. In both instances, the incinerators were required to meet either the most stringent applicable NSPS (Subpart 0), or to meet an emission limited based on a proration of the two applicable subparts in a manner acceptable to USEPA. Each of the three co-incineration projects expected to be operating over the next five years will be required to meet different emission limits. The planned co-incineration facility in Harrisburg, Pennsylvania, is considered an existing facility, and will not be subject to the NSPS. The incinerator will remain subject only to the state emission limit for existing municipal incinerators. An emissions test will be performed, however, once the incinerator begins to burn sludge. Although the incinerators in Stamford, Connecticut, were built in'1975, and therefore are subject to the NSPS, the emission limit currently applied to the facility is the state emission limit for existing sources of 0.4 pounds particulate per 1,000 pounds flue gas. Emissions tests are currently being planned, however, to determine which subpart of the NSPS applies to the incinerator. Subpart E was applied to the Glen Cove, New York co-incineration facility. A test program is currently underway and a final determination will be made at the conclusion of these tests. Future Policy NYSDEC's main. concern is concentrations of heavy metals in the sludge. A significant controversy between NYSDEC and the developer of the Glen Cove, Long Island co-disposal plant over heavy metals concentrations delayed the permit process by over a year. The New York State Department of Health, with NYSDEC's support, is presently developing risk assessments for heavy metals concentrations. The complexities involved in operating a co-incineration facility makes prediction of emission characteristics difficult because of the potential for inconsistent burning conditions. In view of this, obtaining a NYSDEC permi.t may be an arduous and expensive process which may not result in a permit at the end. According to NYSDEC officials, local governments that want to co-incinerate sludge and refuse, prefer to get the refuse incinerator on line first and then use it for co-disposal. 193 SECTION 5. SITING SLUDGE MANAGEMENT FACILITIES Acquiring Land Land may be needed to implement regional or inter-county sludge management s o I u t i o n s .If public land is not available, a parcel or parcels will have to be acquired. Availability of public land should be invest .igated before looking at private lands to save the extensive costs and time involved with acquisition. Should it be necessary to purchase private land, the most cost effective means of doing so is through negotiation based on current fair market value established by two or more independent appraisers. A reasonable time, perhaps one year, should be allowed for land negotiation and acquisition. In the event that negotiation fails, the land may be acquired through condemnation pursuant to the Eminent Domain Procedure Law. The power of eminent domain is specifically reserved to a level of government only within the jurisdiction of that level of government, i.e. a county can condemn land only within the county. If a multi-county authority were to operate a regional facility, it would need acquisition capability in its statute. A s ummary of the procedure for condemnation of land is provided in Appendix 0. Cost of Acquiring Land Acquisition costs include land, appraisals, legal counsel (condemnation will increase this cost substantially), filing fees and costs of notices and hearings. Facility Siting Criteria General criteria for the siting and design of a proposed sludge management facility are provided in state solid waste regulations (6NYCRR Part 360) which detail construction, design and closure requirements applicable to any landfill. NYSDEC regulations contain requirements applicable to sludge incinerators. All these regulatory measures contain constraints that preclude locating a sludge management facility in areas considered to be unique or sensitive. Adherence to the provisions of these regulations and other pertinent criteria should ensure that the sludge management facility is not a source of environmental pollution. Some constraints listed in Table 50 exclude particular areas from consideration, significantly reducing the number of potential locations that may be considered. 194 TABLE 49 SLUDGE MANAGEMENT FACILITY SITING CONSTRAINTS Applicable only to Landfill and Thermal Reduction Siting Consideration Constraint Basis Hydrogeologic Zones Not over a principal aquifer NYSDEC Policy Floodplains Prohibited 6NYCRR Part 360 Freshwater Wetlands Prohibited 6NYCRR Part 360 Agricultural Soils Prohibited 6NYCRR Part 360 (Class 1 and 2 Soils) Depth to Groundwater More than five feet 6NYCRR Part 360 Airports Not within 5,000 feet for 6NYCRR Part 360 piston-powered aircraft only. Not within 10,000 ft. for turbojets Endangered Species Damage to species or 6NYCRR Part 360 critical habitats prohibited Coastal Areas Must be consistent with NYSDOS* Coastal existing use Management Program Wild, Scenic and Development generally Environmental Recreational prohibited Conservation Law River Corridors New York State Department of State Other constraints may be considered at the local level, such as establishing minimum distances from parks, schools, hospitals or nursing homes; locating on a federal or state superfund site; siting so as to avoid damage to archaeological or historic sites or significant habitats, and use of land already developed or dedicated for specific purposes. Size of Sludge Facilities The size of the sludge management facil-ity is of primary importance in both the siting and impact analysis of the proposed facility. Each facility should be planned for a 20 year operating life. 195 The size of a landfill for sludge depends on several factors including which counties, towns, and cities will use it and the projected waste stream quantities for the next 20 years for each participant. Due to the large number of factors that may affect the amount of sludge received at a proposed facility, no single projection of required site acreage could be developed for this study. This kind of evaluation would have to be done, when specific disposal locations are contemplated. Site Selection Process Site selection proceeds by progressively applying siting constraints and criteria in stages (screens) to methodically determine the most suitable potential sites. This screening procedure is designed so that at each stage only areas not eliminated in the previous stage are considered further. To make the process as efficient as possible, each subsequent screen requires a more detailed evaluation than the preceding one. Screen One In the first phase, analysis maps are used. Siting constraints are overlain on the maps. Areas which are excluded from further consideration due to regulatory and technical considerations can then be identified. Screen Two At this stage, the eligibility.of a potential site depends on a number of criteria including environmental health, technical, institutional, social and cultural concerns. Both the size and extent of impacts, as well as the ease of development wil 1 be determined by these features. one convenient way to directly apply these, criteria to potential sites is through the use of an evaluation matrix as contained in Figure 36. The matrix compares the relative strengths and weaknesses of different sites. To use the matrix, each environmental feature is rated based on the extent to which it contributes to or facilitates site development. A relative weight is assigned to each siting consideration. The percentage of weight for each siting factor is then assigned, with each siting consideration category totalling 100 percent. The entries in the matrix, then, are the rating values, usually on a scale of I (poor) to 3 (good). Such an evaluation matrix provides a convenient overview of the strong and weak features of each potential sludge management facility site. The ratings for each category are totalled in an attempt to eliminate the poorer sites from further consideration and to identify Sites that appear to be favorable. 196 SLUDCE MANAGEMENT FACILITY SITE EVALUATION MATRIX. Rating: Site Name: .I- Closely conforms to desirable site conditions. 2- Site has problems conforming to desirable site conditions. Site Location: 3- Site is undesirable. of Siting Rating Siting Sum of Siting Siting Siting Criteria Consideration is 29 Criteria Criteria Consideration Consideration Consideration Weight or 3 Scores Scores Weight Score Population Population within 0.5 Dens' miles of the site Ity boundary The projected popula- tion and the rate of growth for the-area within 0.5 miles of the site boundary during the 20 year period following initial site operation laR!!1alion Population for areas Adjacent to within 0.5 miles of Transport anticipated transporta- Route tion routes. The projected population and the rate of growth for areas within 0.5 miles of the 131 transport routes during the 20 period following initial site operation a% :i:tin S 0 f Crit egis C=rite r is Scor: Scor es@ e r SITE EVALUATION MTRIX %-o i@ I @tii n g@2 1@a t i -ng Siting --Eu-z of- Siting Siting Siting Criteria Consideration 1, 2, Criteria Criteria Consideration Consi derat ion Consideration Weight or 3 Scores Scores Weight Score Contamination Ground and surface of Ground and water aspects @urface Waters Runoff Hydrogeological characteristics Water Supply Relationship to water Sources supply sources Air Quality Atmiospheric stability Prevailing wind direction OD Wind speed Areas of Risk of subsidence Mineral Exploitation Treservation Developmental and .of Endangered, operational impacts on Threatened and endangered, threatened Indigenous and indigenous species Species or critical habitat fonservation Proximity to historical of Historic or cultural resources and Cultural Resources % of Sitin __iat -ing Sit ing SLun of Siting Si L ing Siting Criteria Consideration I , 2* Criteria Criteria Consideration Consideration Consideration Weight or 3 Scores Scores Weight Score Noise 2uality Prevailing Wind Direction Wind Speed construction Impacts Operational Impacts Leachate Proximity to Large Body Control of Water Treatment Proximity to Stream Impact of Off-Site Treatment Topography of Flat Terrain Site . Hilly Terrain Depressed Terrain Proximity to Greater than 251 Groundwater 20 to 251 10 to 201 5 to 101 ,ng e Consid _rat ion Sc or ej AIL SITE EVALUATION MATRIX a -S I Siting % o Siting Rating Siting SWn of Siting -ing Consideration Criteria Consideration 1, 2, Criteria Criteria Consideration Consideration - Weight__ or 3 Scores Scores Weight Score- Open Space Proximity to open space Recreational and recreational and Visual resources Impacts Relationship to scenic views or vistas Degree to which proposed facilities are readily noticeable to passersby ProximiLy to Proximity of site to Sources of Towns with greatest Waste waste generation Generation 0 Consider only Towns C) which will use Regional site Land Ownership Present Zoning Land Use and Zonin Future Zoning Public owner Private Owners Size of Site Greater than 400 acres 200-4CO acres 100-200 acres 50-100 acres Less than 50 acres % of Siting Rating Siting Sun of Sit -ing Siting Siting Criteria Cons i deraL ion I , 2, Gri ter i aCriteria Consideration Consideration Consideration Weight or 3 - Scores Scores Weight Score Transportation Mode,of transportation Assessment Accident rate to trans- port route Structures within 0.5 miles of the transporta- tion route Transportation restric- tions Nature and volume of waste being trans- ported Rroximity to Proximity to airports Incompatible Structures Proximity to other incompatible structures Utility Lines Proximity to major utility lines Municipal Consistency with the Effects intent of master land use plan ,Consistency with local laws, ordinances , rules and regulations Public expense/revenue tradeoffs Ah Siting a Landfill for7the Ash-Residual.from Incineration Unless a landfill is already available within the region for disposal of the ash residue from incinerating sludge or sludge and municipal solid waste, one will have to be constructed, or the ash will have to be hauled outside the region. Some communities are hauling ash to distant landfills at considerable expense. This option may not be available for long, however, as many of these landfills are deciding to retain space for the needs of their surrounding communities. If an ash landfill (ashfill) must be constructed, the following items should be considered. Construction 1. If the ashf ill is to be located in an area near a sole-source aquifer, double liners are required, each of a different chemical composition ( synthetic , or clay liner) with two feet of thickness and synthetic liner separations. 2. A leachate collection system is needed, one system for each liner. A leachate treatment and disposal system is also required. 3. Surface.drainage must be provided: to prevent any uncontrolled ash from reaching surface waters to prevent erosion of landfill surface 0 to minimize surface ponding and infiltration of rain watet into the various sections of the ashfill. 4. Dust control measures must be instituted to prevent ash from drying and dispersing during transporting or landfilling, and becoming a nuisance or a health hazard. 5. Adequate separation of the facility from any natural surface waters must be maintained. Monitoring 1. Groundwater monitoring wells should be installed on site. 2. Baseline (existing water quality) conditions for both surface and groundwater at the site should be established. through testing prior to operation of the ashfill. 3. Water monitoring should be done periodically. 202 Operation I . Cover and compaction needs, including daily, 30 day, and final cover requirements must be planned. 2. Soil cover integrity must be maintained and grass or ground cover established within four months of closure of a waste cell. Additionally, plans for closing the ashfill must provide for: a. a closed facility which minimizes surface ponding and infiltration into the ashfill cells, and protects the environment from leachate contamination of ground and surface waters b. post-closure groundwater and surface water monitoring, maintenance and, if necessary, remediation for five years after closure. Financial Requirements 1. The owner or operator must post financial guarantees such as pollution liability insurance or performance bonds as security against the cost of remediation and developing alternative water supplies in case of contamination. 2. Financial guarantees must also be provided so that sufficient funds exist to ensure proper operation and maintenance of the leachate collection and treatment system after the ashfill is closed. This is not an all inclusive list. The costs of implementing these design considerations will vary depending on the actual site selected. They should be reviewed as part of the plans for the recommended site. 203 Host Community Incentives Any plan for a new regional , inter-county or intra-county management fac ility should consider incentives for the community in which the facility will be located (the "host community"). These incentives might be direct payments to the community or might be in the form of improvements and services not otherwise affordable by the host community.z Incentives are usually negotiated between the host community and the developer of the facility. With either a regional solution, or one involving several counties, all parties would contribute to the incentives. Any incentives are specific to the type of facility being developed, the nee ds of the host community and the developer's and participants' available financial resources. Possible incentives include: 1. An annual payment in lieu of taxes based on the unimproved value of the site at the time of acquisition. A further incentive would be to have the evaluation based on the highest and best use of the land. 2. Additional revenue in the form of a royalty per ton accepted at the facility could be imposed and returned to the host community for either specified purposes (access roads, utilities) or unspecified purposes (parks, redevelopment, new local services). These payments could be adjusted periodically. 3. A post-closure fund could be established for which dedicated monies may be used by the host municipality, if necessary, to make repairs to the closed facility. Post closure is required by NYSDEC regulations for some t ypes of facilities. 4. Infrastructure rehabilitation required as part of the facility's development could be guaranteed by the developer or operator. 5. The host community could be guaranteed future participation in the preparation of all contract documents and agreements related to the planning, design, construction and operation of a regional facility. 6. The host community could be guaranteed participation in any board, committee or legal structure relating to the facility. 7. Property owners within a given radius could be guaranteed fair market value for their property, based'on a valuation made prior to thedevelopment of the facility, plus an inflation factor based on local real estate values. This offer would be good for a predetermined period from the start of construction. Alternatively, property owners could be compensated for any losses in property values attributable to the facility. 204 Potential Sites The sites shown on the maps on the following pages were developed from draft and final planning documents furnished by the seven counties. As the objective of this study was not specific site selection, this siting information is for illustrative purposes only. The siting criteria used for the sites shown here may not necessarily be the same as the criteria required for sludge management facilities. Therefore, these sites may or may not meet all the appropriate siting criteria for sludge management s i t e s .The selection of a final site, or sites, depends on the type of facility to be constructed and the quantity and quality of wastes to be managed. 205 POTENT I'A L S I T ES ULSTER Site C -site A hudson s i t e river SITE A - Clay pit sites near Kingston. SITE B - A land area in the northeastern part of the Town of Gardiner. SITE C - Land areas adjacent to the existing landfills in the Towns of Kingston Shawangunk and Saugerties. Source: Solid Waste Management Study for Ulster County, February 1985, by Barton & Loguidice, P.C. 206 POTENTIAL SITES 14ESTCHESTEIR"@\\ hudson ri v 'r no sites over %\% 100 acres % Source: Report on 201 Facilities Planning for Sludge Treatment and Disposal, June 1978, by Greeley and Hansen. 207 POTENTIAL SITES ORANGE site D site E s it.e F site C 7 i site H %46. site G siteB si te A SITE A - A 750-acre area located northeast of the intersection of NYS R oute 42 and Peenpeck Road in the Town of Deerpark. SITE B - A 790-acre site located southwest of the intersection of County Route 22 and Toad Pasture Road in the Town of Minisink. SITE C - A 650-acre site in the Town of Goshen, bounded by Maple Avenue, Houston Road, NYS Route 17A, County Route 6 and Cross Road. SITE D - A 590-acre site, south of County Route 66 and west of Johnson Road in the Towns of Goshen and Chester. SITE E - A 400-acre site east of Tuthill Road and south of NYS Route 208 in the Town of Blooming Grove. SITE F - A 500-acre site west of East Searsville and Mills Road, and south of Beamer Road in the Town of Montgomery. SITE G - Existing landfill best site accessibility, lowest haul cost and % development cost. SITE If Stewart Airport former Monteco Site. Source: Draft Alternative Action Study, Orange 6ounty Landfill Expansion, August 19951@ hv O'B-rien & rm-re Inc. 208 POTENTIAL SITES site B site A si '-e @- e C W [email protected] Joke folk PUTM M . ...... .... .'-e-okooo@- site siie D h ud son river SITE A - A site on Ludingtonville Road, in Kent, adjacent to Interstate 84 at Exit 17. "r SITE B A site in Kent on Ludingtonville Road, to the north of the New York State Department of Transportation Facility. SITE C A site in Patterson northeast of Interstate 84 at Exit 18 on the south side of Route 311. SITE D - A site in Southeast on the south side of Route 312, northeast of Interstate 84 at Exit 19. SITE E - A site in Southeast on the southeast corner of the intersection of Routes 312 and 6. Source: Central Fransfer Station Site Evaluation, Phase II Study, May 1985, by Velzy Associates. A 209 POTENTIAL SITES hud s-o n r i v e r site C IROC s i t e A site B SITE A - Vacant parcel east side of railroad tracks on Rockland County Sewer District No. 1, Orangetown, New York. SITE B - Vacant parcel adjacent to Ciba Geigy plant in Village of Suffern, Town of Ramapo. SITE C - Vacant parcel on Tilicon Quarry property north of Long Clove Road, Clarkstown, New York. Source: Rockland County Sewer District No. 1, Sludge Management Facility Plan Amendment Report, April 1986, by Metcalf & Eddy, Inc. e, @Fj ]<LAN 210 POTENT I A-L S I TES SULLIUAN site A - ---------- cle I awa e river SITE A - Monticello Landfill Site. No current source of siting information. 211 POTENTIAL SITES Ll CHESSI huds 0 river @n-s"i @e s o v e r a c ip e s No current source of siting information. D 212 SECTION 6. DEVELOPING, FINANCING AND IMPLEMENTING SLUDGE MANAGEMENT PROJECTS Introduction This section presents important considerations for planning sludge projects, exclusive of engineering design. It describes the following: � procuring services such as design, construction, operation and maintenance and total service contracts � institutional mechanisms such as local authorities and agencies, state agencies, county districts, intermunicipal agreements, privatization and host community incentives * financing options � revenue sources and grants Procuring Services for Sludge Management Projects In the development of any project, one of the more difficult tasks is the actual procurement of services. Such services include design, construction, operation and maintenance and total service contracts. This section describes the available mechanisms for procurement which are presented in Table 50. Procurement Guidelines Generally three approaches are used to procure professional and technical services for projects: 1. the conventional approach with separate engineering and construction contracts, 2. a turnkey contract where the facility is designed and built by the contractor and turned over to the owner for operation, 3. full service contract by the developer for the design, construction, and operation of the facility. Bidding Procedures Competitive selection is the basic requirement for public procurement. A variety of procurement procedures are used by state and local governments: 1. Competitive Sealed Bidding or Formal Advertising. An invitation for vendor bids is issued which contains detailed specifications. In evaluating vendor responses, the municipality may use only objective factors to determine that the item or service being offered satisfies the requirements of the notice. Award is made on an objective basis to the lowest responsible bidder. 213 2. Competitive Negotiations. These are generally used for a specific service. Extensive discussions are held with potential contractors to determine the fairness and reasonableness of the negotiations. A competitive sealed proposal is requested through a request for proposal (RFP) procedure. Proposals are then evaluated for compliance with the requirements of the request for proposal and from the standpoint of costs. Often some changes in proposals may be needed to arrive at the final offer. However, all procedures must be in accordance with state and local laws. 3. Two Step Formal Advertising. This is used by the federal government where the complexity of the system or service desired precludes the preparation of detailed specifications. In step one, the RFP is issued and unpriced technical proposals are submitted. Discussions are conducted separately with all proposed bidders to ensure mutual understanding which will allow the submission of more responsive answers to the formal request for proposal. In the second step, the notice for the actual project is submitted through an invitation for bids similarto the compeLitive sealed bidding procedure. 4. Sole Source Negotiation. This involves no competition and is used where a particular project is so narrowly described that only one responsible bidder can be anticipated. There are limitations imposed by law in New York State on all of these procedures. These must be followed to afford the best competitive advantage to the municipality. Procurement Alternatives Table 50 summarizes the procedures available to various government entities. A 214 TABLE 50 SUMMARY OF PROCUREMENT PROCEDURES Permitted Procurement Statutory Authority Procuring Body Procedure(s) to Use Procedure Municipality Competitive Seale d Bidding General Municipal Law 103, 120-w Request for Proposals General Municipal Law, 120-w Local Authority Competitive Sealed Bidding, General Municipal Law, Request for Proposals, 120-w, Special Special Procedures Legislation Industrial Develop- All options available to the Article 18-A of General ment Authority private sector--essentially, Municipal Law no limitations County Competitive Sealed Bidding, General Municipal Law Request for Proposals 103, 120-w New York Power Competitive Sealed Bidding, Unconsolidated Laws 7178 Authority Competitive Negotiation, Two-Step Formal Advertising, Sole Source Negotiation New York State Competitive Sealed Bidding, State Finance Law 135, Environmental Requests for Proposals 139-f; Public Author- Facilities ites Law 1287; General Corporation Municipal Law 120-w New York Power Competitive Sealed Bidding, Permitted, but not Authority Competitive Negotiation, required by State Two-Step Formal Advertising, Finance Law 135 Sole Source Negotiation New York State Urban Competitive Sealed Bidding State Finance Law 135, Development Corpora- UDC Act 6261 tion New York State Energy Competitive Sealed Bidding, Public Authorities Law, Research and Develop- Competitive Negotiation, Section 1850 ment Authority Two-Step Formal Advertising, Sole Source Negotiation 215 Institutional Mechanisms for Sludge Management Projects Introduction A number of alternative institutional mechanisms are available for local government to build, design, finance and operate sludge management facilities. Individual towns or villages may construct and operate individual systems. At the county level, a facility may be built by the county itself, by a county district, or by a local authority. At the state level there are a number of public authorities or public benefit corporations which can assist in the planning, design, construction, operation, maintenance, and financing of such a facility. In addition, private companies are now developing local projects in the waste management field either on their own or for municipalities (privatization). Available Mechanisms Table 51 at the end of this section indicates various state and local mechanisms that can be used for the development of a specific sludge management project. The county may decide to assume the project under its power and as a function of county government under county law. If only a part of the county is involved, a county district can be formed which may include noncontiguous. areas. The specific service area is thus delineated and fees apportioned appropriately. Another local development mechanism is an intermunicipal agreement. In this, one municipality may take the lead and share the costs and responsibilities in accordance with the terms and conditions of the intermunicipal agreement. A final local mechanism for project development is the establishment of a local authority. This would be a public benefit corpor 'ation chartered under the State Public Authorities Law and established pursuant to an act of the State Legislature in accordance with the State Constitution. The specific powers of a local authority to develop a project are legally delineated and an appropriate blend of public/private responsibilities can be used. State authorities also have a wide range of powers to assist municipalities in the development of projects. Up to five authorities can do these projects if they are for solid waste. The Port Authority of New York and New Jersey and the New York Power Authority build their own projects in acc ordance with their legislative mandates or charters. The New York State Energy Research and Development Authority handles projects which are resource recovery facilities specifically in connection with utilities. The Urban Development Corporation (UDC) and the Environmental Facilities Corportion (EFC) have a variety of mechanisms available under their respective statutes to assist municipalities in the planning, design, and construction of a facility. UDC has had limited experience in solid waste whereas EFC is specifically authorized by law to engage in solid waste management projects. Each of these mechanisms, local and state, are described further in the accompanying table. 216 Because the capital costs for many municipal environmental projects are high and the systems complicated, private vendors are now offering to own and operate local liquid and solid waste projects. This is known as privatization. These vendors find it is in their interest to control the process through their own operation. This concept facilitates the financing, offers a fixed service cost to the municipality which may be lower than the municipality's cost, and provides tax advantages for the private owner. These tax advantages include investment tax credits, accelerated depreciation, and interest and rental deductions. The current federal tax proposals could have a serious impact on financing through a private owner. The proposed federal legislation would repeal investment tax credits and institute new depreciation schedules. Further, this proposal would also change the allocation rules for the sales of industrial revenue bonds in the state. These developments must be followed closely until the final federal changes are adopted and a new analysis made for the optimal financial and ownership structure of a project. The alternatives presented in Table 51 should be- studied so that once local needs are defined, they can be addressed by the appropriate vehicle. It may be that complete local control and ownership is required or, if that is not an important consideration, the authorities ass-isting at the state level can own, operate and finance the facility. Early planning and selection of the developmental mechanism to be used is essential. Most mechanisms that co uld be employed are legally complex and, in many instances, require input and contribution not only from the general public in areas to be served, but from institutions such as banking and industry and developers of specific projects. To begin the preliminary planning, it is best to initially examine all factors involved in the development of a project. Technology, financing, revenue, grants, and public/private mechanisms all are factors which must be considered and weighed before a municipality can decide the best course to follow. However, use of an existing state authority or establishment by the legislature of a multi-municipal authority with special powers will provide the best management base and greatest flexibility. 217 TABLE 51 INSTITUTIONAL MECHANISMS FOR SLUDGE MANAGEMENT PROJECTS MECHANISM DESCRIPTION DISCUSSION FUNCTION Local Mechanisms County The legislative body of the county may The county can provide recycling centers, To implement a county sludge appropriate and expend monies for the transfer stations, hauling facilities rail management project. management of sludge. May acquire, or barge haul facilities, processing ;ystems, construct, operate and maintain the and other solid waste reduction, treatment, necessary facilities for such manage- disposal, or conversion systems. Construc- ment. (Reference: County Law 226-b.) tion requires compliance with the New York State General Municipal Law and Municipal Finance Law. The county may enter into nec- essary contracts for development directly or with a public authority. co Local An LA is a special public authority The local authority may be granted the To implement, develop and Authority established by an Act of the State powers to collect, transport, process, and finance a county or local sludge (LA) Legislature pursuant to Article IV, dispose of sludge and septage, design, con- management project through revenue Section 5 of the State Constitution. struct, and operate a sludge management bonds. The act identifies the purposes and facility; sell any byproducts; contract for powers given to the local authority. loans or grants with other municipalities, (Reference: State Constitution, public corporations or persons; contract for Article IV, Section 5.) the design, construction, operation, main- tenance, and financing of a sludge management facility. County The county may appoint, establish or Powers include collecting data on the To compile information related to Agency designate an existing administrative problems of collection, conveyance, treat- the development of a county sludge body or public authority to act as its ment and disposal of solid waste and sludge management project. agent to assemble data on sludge manage- within the county. May employ engineering, ment. (Reference: County Law 5A.) legal, and other professional advice as necessary and budgeted. Where available, it may render technical assistance to local municipalities. Oil a TABLE 51 INSTITUTIONAL MECHANISMS FOR SLUDGE MANAGEMENT PROJECTS MECHANISM DESCRIPTION DISCUSSION FUNCTION County A county may establish a district The district, as an agent of the county, To implement a sludge manage- District under Article 5A of the NYS county would designate the service area of the ment project. law for collecting and disposing proposed project and carry out the functions of garbage, sludge and septage. delegated to it by the county. Such dis- It may consist of two or more non- tricts require the approval of the State contiguous areas within the county. Comptroller. When designated by the county, it can act as the county agency to plan and develop a sludge management project. (Reference: County Law 5A.) N Intermunicipal Agreement between two or more munici- The agreement can provide for allocating To act as the joint venture Agreement palities for contractual cooperation costs and revenues, and for contracting, and mechanism for a common sludge to perform joint enterprises which acquisition and sale of property. it can management project. they are entitled to perform individ- make claims for grants on behalf of the ually under law. (Reference: General individual participants, and perform the Municipal Law 5-G.) tasks of the individual municipalities on a joint basis. State Agencies New York State A public authority with broad powers to EFC is empowered to perform any of the To assist the counties, villages, Environmental plan, design, construct, operate, main- actions that a municipality is authorized cities or towns via a county Facilities tain, finance (or combinations of all) to do under applicable state and local laws. contract, intermunicipal agree- Corporation solid waste management facilities in addition, it has special powers to sub- ment or serie's of one or more (EFC) including sludge management projects. contract work and to allow a prime contractor contracts with municipalities to (Reference: Public Authorities Law to act as the coordinator of all construction. develop a sludge management 1290.) project. TABLE 51 INSTITUTIONAL HECHANISNS FOR SLUDGE NANAGENENT PROJECTS MECHANISM DESCRIPTION DISCUSSION FUNCTION New York State A public authority engaged in energy NYSERDA can finance local projects for pri- To finance a private developer of Energy Research research and development projects. vate utilities. Its special powers include a resource recovery plant. Total and Development Like.EFC, it has tax exempt pollution financing energy recovery systems for utility development assistance and pro- Authority control financing with special powers companies. ject management is not available. (KYSERDA) for energy related systems. (Reference: Public Authorities Law 185800.) New York Power HYPA has wide authority to develop NYPA has proposed developing resource To finance, develop and operate Authority projects for generating electricity in recovery projects in local areas which they its own projects. (NYPA) New York. It builds, operates, would operate. Sludge management could be maintains, and finances its own a part of such disposal efforts. An analysis projects. (Reference: Public of the loss of local control of these projects Authorities Law 1010.) should be made before making final decisions. Port Authority PANYNJ is a bi-state agency established PANYNJ has proposed a variety of resource To finance and develop total of New York by interstate compact to develop the recovery projects in the New York City area industrial park projects. and New Jersey Port of New York. It has broad con- that could include sludge disposal. (PANYNJ) tracting powers that include develop- ment of industrial parks. (Reference: Unconsolidated Laws 7173.) Urban UDC, a pub lic benefit corporation, UDC can use its broad powers to finance and To access financial markets use- Development engages in a wide range of development construct its development projects. UDC ful for project development. Corporation projects. (Reference: Urban does not appear to be developing specialized (UDC) Development Corporation Act.) sludge management projects. Private Vendor A private company would take the A private company could offer total To develop a total package (Privatization) initiative in development and provide service, including ownership, operation, for a municipality. a total sludge management service to and a fixed service fee to a local munici- a municipality. pality and group of such local units. Financing Sludge Manageuent-Projects @Financing is integral to any solid waste or sludge management project. Many financing options are available through the public and private sectors or through combinations of both. The final mechanism chosen is generally quite specific to the project. A careful analysis and comparison must be made of all alternatives during the early stages of project planning and development. Table 52 at the end of this section describes each option with attendant advantages and disadvantages. Public Mechanisms A financing package for sludge management should offer a municipality the lowest possible cost with a minimum of financial risk. The appropriate method of financing is generally based on risk and reward considerations and cost effectiveness. The project is usually financed using tax-exempt municipal bonds, general obligation bonds or revenue bonds. General obligation bonds require a municipality to pledge its taxing power to ensure timely repayment of the debt and, therefore, provide a wider base from which to collect revenue. With general obligation bonds the payment of annual debt service is secured by the full faith and credit of the state or local government. Revenue financing, another alternative, is project-specific and the municipality is not liable for the debt service. Instead bonds are secured primarily by a guarantee of fees from the facility which must be applied to retire the debt service. Federal tax law includes restrictions on the issuance of tax-exempt bonds. The Tax Reform Act of 1986 creates a unified volume cap for' Industrial Development Bonds (IDB), including for small issues, of $75 per capita or $250 million through 1986 and 1987. In 1988, the cap drops to $50 per capita or $150 million. IDBs generally are either revenue or general obligation bonds used directly or indirectly to finance a trade or business. Under the new tax law, revenue bonds issued for certain government -owned airports, docks, wharves, and solid waste facilities are not subject to state volume caps but are subject to the minimum tax if more than ten percent of the proceeds of the bond issue is used for a non-governmental purpose. The Tax Reform Act also repeals the investment tax credit for assets placed in service on or after January 1, 1986 (with certain transition rules). The law provides that real property financed with the proceeds of small issue bonds must be depreciated over 40 years using the straight line method. Equipment financed from bond proceeds must be depreciated on a straight line basis over the asset depreciation range mid-point life of the particular equipment. 221 Private Mechanisms The best financing solution for a municipality is to minimize the debt dir ectly incurred while providing sufficient incentives and benefits to the private developer for the construction, operation, and financing of the sl udge management facility. These incentives may involve tax-free interest on bonds, tax deductions for interest or rental payments, accelerated depreciation and private sector bonding, if available. Although a number of government agencies have authorization for specific financing programs, actual assistance is extremely limited due to present national administration policies of minimizing federal involvement in matters that are considered to be local problems and responsibilities. Federal Small Business Adminis'tration assistance programs have been virtually eliminated. Public/Private Mechanisms While six New York State public benefit corporations can assist in financing resource recovery projects, not all can provide assistance for sludge-only projects. Those that do are: New York State Environmental Facilities Corporation, New York State Energy Research and Development Authority, New York Power Authority, Port Authority of New York and New Jersey, the Urban Development Corporation, and the Job Development Authority. Of these six authorities, the Power Authority finances only its own energy projects. The Job Development Authority has had a cap placed on its pollution control financing and would be of little financial assistance to municipalities. The Energy Research and Development Authority has largely confined its private financing activities to those for public utilities, and the Urban Development Corporation's reports describe only one related project, a resource recovery plant, which was part of a general redevelopment project. The Environmental Facilities Corporation has very broad powers to assist municipalities and private entities in all phases of project development and financing. It may assist private industry through its industrial pollution control financing program or other financing programs. Each public benefit corporation is tailored to the specific purposes of its enabling legislation. Powers vary widely and each must be evaluated in terms of the specific project. Certain bonds issued by state and local governments may be tax exempt. A local authority authorized by a special act of the State Legislature can provide either public or private ownership and financing or combinations of both. For example, a local authority could do the revenue financing for a private developer. A sludge management facility might be owned by a private developer with financing available only through the local authority's revenue bond structure. In Dutchess County, for example, a local authority was constituted by legislative act to finance a resource recovery plant. The County will own the facility when completed, while a Pennsylvania engineering corporation will design, construct, and operate the plant. 222 Local Industrial Development Authorities (IDA) have been used for project development for solid waste and resource recovery. Under these arrangements, the IDA owns the project until the bonds are paid. Resource recovery projects in Peekskill, Westchester County and Glen Cove, Long Island used IDA financing. A local development corporation can provide technical and financial assistance. While it may develop and operate commercial facilities, it does not do financing. 223 TABLE 52 FINANCING NECHAVISMS FOR SLUDGE MANAGEMENT PROJECTS MECHANISM DESCRIPTION ADVANTAGES DISADVANTAGES Public Mechanism General A financial obligation of debt Referendum approval indicates sup- Use of these issues for solid waste projects Obligation secured with the full faith and port for project. Full faith and which approach the goverment unit's bonding Bonds credit of the issuing entity. Debt credit backing generally enhances limit may displace or prevent the use of service is paid from the general the marketability of the bonds. bonds for other local capital projects. fund of the.issuing source. Typically, General obligation bonds of state Issues are subject to voter approval. In the bond issue is subject to a public authorities may be backed by the times of austerity, bond issues may be un- referendum. "moral obligation" of the state. popular. Approval of state moral obligation the credit rating of the issuers issues is virtually impossible. The credit determines the financing cost and rating would be that of the municipality. 41 not the technical merit of the pro- ject. interest-on bonds is generally tax-exempt. Special A financial obligation of debt which Revenue bonds are issued for a The 1987 federal tax law severely limits or Revenue is secured by the anticipated stream specific project, and do not eliminates tax exempt status for certain Financing of revenue generated by the project. interfere with other capital pro- of these issuers. Revenue projections State and local issues for solid waste ject general obligation financing. must be analyzed against varying marketing disposal may be exempt from tax on the Issues are generally tax-exempt. conditions for-the recovery projects. the interest. Financing by certain Revenues from a project are used state authorities require Public to meet debt service obligations. Authorities Control Board approval. Revenue bonds are not subject to constitutional debt and bonding limits. 1 ilk 16 TABLE 52 FINANCING MECHANISMS FOR SLUDGE MANAGEMENT PROJECTS MECHANISM DESCRIPTION ADVANTAGES DISADVANTAGES Leveraged A financial package that combines Lower interest rate achieved by This type of financing is relatively new, Lease several financing mechanisms to pro- lessee through private ownership by and extremely complex. At the end of the Financing vide participants with either tax lessor which can obtain tax advan- lease the facility is owned by the lessor. benefits or lower financing costs. tages a government cannot. The If the implementing agency (lessor) can It generally involves 2 major parti- municipality can arrange to buy the achieve the same tax benefits, there is no cipants: a financial intermediary project at the end of the lease at benefit to the lessor. Financing charges (lessor) and an implementing agency fair market value or renew the are subject to lessor's ability to obtain (lessee). Lower long term capital lease. Private industry can supply good rates. May not be a real alternative and interest benefits accrue to the capital at effectively lower rates. since the non-related third party which is implementing agency if a lessor is This enables a municipality to necessary may only be interested in tax interposed between the long-term *avoid raising capital in the mar- benefits. This option is not favorable ource of capital and the agency. ket. Service company can own and under new federal legislation. The private company lessor receives reserve rights to sale for tax the tax advantages of ownership and purposes to a third party. the agency, in turni receives benefit from lower charges from the inter- mediary. Iadirect Several tax benefits have been Private owner receives indirect Under 1986 tax law, these benefits are Federal available in the past for private assistance not available to public reduced considerably. Assistance ownership. ownership. TABLE 52 FINANCING MECHANISMS FOR SLUDGE MANAGEMENT PROJECTS MECHANISM DESCRIPTION ADVANTAGES DISADVANTAGES 1. Investment Until Tax Reform Act of 1986 owners N/A N/A Tax Credits of a facility could claim a direct deduction of a 10 percent investment tax credit. The new tax law repeals the investment tax credit with respect to property placed in service after December 31, 1985. The only exception to this applies to property that meets a transition rule for depreciation. In this instance the credit amount (for transition property) is reduced by 35 percent for taxable years beginning after June 30, 1987 with a phase- in for earlier taxable years. A tax- payer is required to reduce the basis of its transition property for depre- ciation by the full amount of the credit after the 35 percent adjustment. TABLE 52 FINANCING MECHANISMS FOR SLUDGE MANAGEMENT PROJECTS MECHANISM DESCRIPTION ADVANTAGES DISADVANTAGES 2. Accelerated Accelerated depreciation allows a Faster write-offs encourage capi- HR3838 (Tax Reform Act of 1986) modifies Depreciation faster write-off mechanism for capi- Lal investments. the Accelerated Cost Recovery System by tal investments. adding four additional classes into which property may be categorized and by providing for more accelerated depreciation. The cost of real property will be recovered on a straight line basis. The tax law also provides an Alternative Depreciation System (ADS) for certain categories of property including property financed with the proceeds of tax exempt obligations. The cost of ADS property must be recovered on a straight line basis over its class life, Asset Depreciation Range midpoint life. Real property must be recovered over 40 years. The cost of solid waste disposal facilities must be recovered over its class life (generally 10 years for waste reduction and resource recovery projects). TABLE 52 FINANCING MECHANISMS FOR SLUDGE MANAGEMENT PROJECTS MECHANISM DESCRIPTION ADVANTAGES DISADVANTAGES 3. Interest or interest on bonds of state and Interest deductions and rentals Tax Reform Act of 1986 provided a more Rental local governments exempt from reduce net income, tax liability restrictive concept of private activity Charges taxation. Rental charges on leased and enhance profit margin. bonds (any bond that satisfies a private property are operating expenses (interest for state deduction is business use or private security test). and deducted from revenues before still intact.) Interest on private activity bonds will be -income is determined for the private taxable unless the obligations are company. characterized as qualified bonds. Private Various investment tools are available financing -to the private sector which are not OD available to government units. 1. Equity An arrangement where one or more Private capital is put at risk and Requires availability of investors. Investment firms invest capital in expectation thus obligation of municipal re- Competition may exist from high interest of returns greater than can be returned sources is reduced. alternatives elsewhere. from interest investments. 2. Debt one or more firms may issue corporate Private capital is put at risk and Subject to availability of markets for Financing debt in conjunction with the equity thus obligation of municipal re- corporate issues. investment. sources is reduced. 3. Industrial Interest on obligations of the bond interest is excluded from gross in- Must be for an eligible item under Section Revenue sale by the political subdivision come of bond holder. Developer's 103 of the Internal Revenue Code. Federal Financing is excludable from the gross income credit backs the issue. legislation has placed a "cap" on each of the bond holder, provided bonds state's financing entities based on a per are for an eligible activity and capita limit of $75/person. Per capita are paid for by revenues from the limit of $50/person is scheduled for project. January 1, 1988. Pollution control issues are eliminated under Tax Reform Act 1986. All TABLE 52 FINANCING MECHANISMS FOR SLUDGE MANAGEMENT PROJECTS MECHANISM DESCRIPTION ADVANTAGES DISADVANTAGES Private Business Federal Assistance 1. Small SBA's purpose is to aid, counsel, Guarantees of@financing give small Because eligibility is limited to Business assist and protect the interests companies access to money markets small business, capital requirements Administra- of small business by various means at better rates than might other- for larger-scale resource recovery tion including loans to small business wise be possible. Useful for small Projects would probably preclude use (SBA) concerns and small investment con- contractors who may be involved of SBA. SBA will back loans only cerns, and to guarantee surety in resource recovery construc- after all other private banking bonds for small contractors. It tion or investments. "Minority attempts have been exhausted. The provides guaranteed, direct or business" assistance would be use-, future of SBA is extremely doubtful. immediate participation loans to ful in government assistance pro- assist firms in meeting air or jects. Some grants are available water pollution standards through for equipment needed by minority 1OOZ backing of loans, leases, or contractors. other contracts. It can also pro- vide management assistance and minority business advice. Economic Does not offer applicable financing; Development grants.only. Administra- tion (EDA) 3. Urban Does not offer applicable financing; Development grants only. Assistance Grants (UDA) TABLE 52 FINANCING MECHANISMS FOR SLUDGE MANAGEMENT PROJECTS MECHANISM DESCRIPTION ADVANTAGES DISADVANTAGES 4. United Does not offer applicable financing; Grant would reduce capital costs. Funds are limited and projects States grants only. must score high on state priority Environmental list. Protection Agency (USEPA) State Financing -Progress 1. New York A public benefit corporation with Bonds can be either special obli- Present state directive limits the types State power to assist municipalities in gation or revenue issues. EFC of municipal projects in which EFC can Envi.ron- the planning, design, construction, can act as agent for all or part engage. Level debt (equal annual payments) mental operation, maintenance, and financing of a project for a municipality or financing for municipal projects is legally Facilities of environmental projects including state agency. EFC is designed to possible. The Tax Reform Act of 1986 Corporation solid waste and sludge management develop a wide variety of environ- eliminates tax-exempt status of pollution (EFC) facilities. In addition, EFC can mental projects. Can provide control financing, and places qualifications finance pollution control and other technical assistance to both public on bonds used for solid waste management projects for private companies. and private clients. Either the facilities. Corporation or the municipality can own the project. EFC has power of eminent domain. TABLE 52 FINANCING NECHANISMS FOR SLUDGE MANAGEMENT PROJECTS MECHANISM DESCRIPTION ADVANTAGES DISADVANTAGES 2. New York A public benefit corporation whose Pollution control financing is tax No grants available except for research or state purpose includes development and exempt per Section 103 of Internal unique demonstration projects. Projects Energy and advancement of new energy technologies Revenue-Code. Has same benefits must be energy related. Pollution control Research and conservation methods. Programs as a local IDA. issues could lose tax exempt status under Development include research, development, and pending federal tax proposals. Authority demonstration of new energy tech- (KYSERDA) nologies, renewable and indigenous energy resources and fossil fuel and electrical systems. NYSERDA also has pollution control facilities finan- cing and special energy programs. W Financing programs enable utilities and other private enterprises to obtain tax-exempt financing. 3. New York HYPA is authorized to maintain an Has wide procurement powers. Can NYPA's interest may be in large projects Power adequate and reliable supply of elec- finance plants throughout the state only. Will finance only those projects Authority tricity throughout the state. NYPA which generate electricity. NYPA which they own, build and operate and are (NYPA) can issue its own general obligation is not subject to Public Authorities energy producers. or special revenue bonds secured by Control Board approvals on financing. assets of, or revenues from, a Can perform construction. special project. 4. Port PANYNJ is a bi-state agency charged Has wide authority to engage in The PANYNJ projects and financing are Authority with developing the Port of New different methods of procurement, limited to the New York City area. of New York York. Created by compact between the including sealed bids, competitive and 2 states. Its master plan includes or sole source negotiations or New Jersey industrial parks with resource re- two-step advertising. The Authority (PANYNJ) covery projects as a means of pro- is not bound to New York State muni- viding low cost energy to industrial cipal laws and can issue either con- clients. solidated or project revenue bonds. TABLE @2 FINANCING MECHANISMS FOR SLUDGE MANAGEMENT PROJECTS MECHANISM DESCRIPTION ADVANTAGES DISADVANTAGES 5. Urban A public benefit corporation which Having both government obligation Must generally comply with municipal bidding Development assists in developing a wide range and revenue financing capability procedures. Only one solid waste project has Corporation of projects including industrial provides great flexibility. Vast been implemented to date. (UDC) and commercial. It is empowered to scope of projects. Experience issue general obligation bonds as with financing. Special powers well as project revenue bonds. to sponsor or organize subcorpora- tions. Can perform construction. 6. Job A public benefit corporation or- Has power to finance job develop- Pollution authorization remaining is Development ganized to improve employment oppor- ment-related projects of private essentially non-existant. Has no present Authority tunities. It assists with financing companies at below market rate. pollution control program. ODA) the construction activities of in- dustries by guaranteeing the loans made by non-profit institutions. Can also loan money to local non-profit development corporations for the cost of machinery and equipment by se- curing an interest in the project and guaranteeing the loans. Can assist in financing projects of businesses in rural areas through the Rural Development Loan Fund. TABLE 52 FINANCING MECHANISMS FOR SLUDGE MANAGEMENT PROJECTS MECHANISM DESCRIPTION ADVANTAGES DISADVANTAGES Local Financing 1. Local A local economic development agency Interest is currently tax exempt. Sludge projects must compete with other Industrial authorized to finance the development Local agency may be in best position uses. Legislation pending in'Congress Financing of local industrial facilities. It to evaluate best local uses of finan- could seriously impair tax advantages. Agency may be a county, town, or local muni- cing. Financing is relatively IDA does not engage in construction as (IDA) cipal agency which may issue indus- flexible. At the end of bond period, do many state authorities. IDAs are trial development bonds for specific the developer has an option to buy subject to state cap limitations. projects. The bonds are revenue the project at a nominal cost, bonds backed by the faith and credit normally one dollar. of the private developer. Interest on the bonds is tax exempt. Tax abatement programs are possible. In the case of developing a facility, the developer requests financing, but title of land and facility rest with the IDA until the bonds are paid off. The facility is leased back to the developer. Short term loans are also available for equipment. 2. Local A local agency created and controlled LDC provides financial and techni- Activities are limited to resources available Development by community organizations to act as cal assistance for construction or through SBA and JDA programs and are thus Corporation a vehicle for commercial development. improvement of industrial facili- subject to uneven or minimal funding. LDCs, (LDC) The LDC must have a minimum of 25 ties. Can also develop, operate unlike IDAs, do not do financing. LDCs are members with 75% of ownership and con- or maintain commercial and recrea- corporations and must function in conformance trol held by local business operators. tional facilities. with New York State corporation law. Federal SBA funds under its Section 502 programs are "passed through" SBA to local merchants. LDCs may acquire, lease, or mortgage both real and personal property. Revenue Sources and Grants Introd uction This section presents the major revenue alternatives available to offset the inherent costs of new and improved sludge management projects. While some of the alternatives are the least desirable (total taxation), others can be used to reduce the consumer's share of costs. Other revenue alternatives such as tipping fees and product sales offer the possibility of reducing user costs. However, many of the revenue mechanisms, because they might involve byproducts, must await the operation or even long term use of the facility. Therefore, initial development costs may still have to be borne by the municipal constituency. The possibilities for grants from various state and federal sources are also reviewed in this section. Grants reduce the net cost to the municipality and are particularly beneficial where the expenditure of large capital costs are anticipated. Revenue Sources Various sources of revenue as well as their major advantages and disadvantages are shown in Table 53. Possible'sources include "charge back" items such as taxation, tipping fees, and byproducts. The various powers of a municipality to raise revenue by taxes are quite broad and could ensure the necessary revenue base for financing a project. They could also provide some of the initial development costs which are subsequently capitalized through long term debt. Byproduct sales play an important role in reducing costs. But they, as with tipping fees, cannot produce revenue until the facility is in use. The table is furnished so the . total project may be developed in conjunction with technology and financing. From a review of sludge and solid waste technology, it is clear that the sale of byproducts can provide a key revenue source. For example, compost can be packaged and sold and land-applied sludge can benefit both the generator and user. The rev;nues derived from byproduct-sales must be evaluated against the cost of producing any byproduct. It is imperative, therefore, to develop a marketing plan and identify potential customers during the project planning to evaluate the precise cost benefits from the capital expenditures required to produce those revenues. Grants New York has been the only state to offer municipalities major grant assistance in reducing the capital costs of solid waste disposal projects. This was established through the Environmental Quality Bond Act (EQBA) of 1972. However, the portion of the act reserved for sludge projects is essentially depleted and very little chance exists for reallotment of funds for projects which have been slow in developing. A new bond act will be presented to New York State voters in November 1986 which may provide new monies for sludge management projects. Federal and state grant funds are 234 virtually non-existent. While most federal programs are still authorized, they are either not being funded or being funded at such low levels as not to be beneficial. These programs must be monitored annually in the event policy changes occur at the state and federal levels which will result in increased availability or new programs. Table 54 shows possible sources of grants. 235 TABLE 53 REVENUE SOURCES MECHANISM DESCRIPTION ADVANTAGES DISADVANTAGES Taxation Procedure used by various levels of Can produce a solid base for Taxes are difficult to levy due to general government whereby a levy is placed assured legal revenue. The more taxpayer opposition. Certain taxes are on the individuals and concerns general taxes provide a wider limited to specific purposes, e.g. revenue within that political jurisdiction. base while special levies can be charges for services used to retire revenue The purpose is to produce revenue used for specific items or ser- bonds can be used only for that purpose. to carry out the various functions vices. User fees in various forms of the jurisdiction. It can take can be developed for a specific the form of income tax, sales Lax, purpose, e.g. water rents, as property taxes, service charges, opposed to ad valorem levies. user charges, special, and ad valorem tax. Tipping Fees A charge levied on all wastes brought User fee charges based on actual Cannot collect until facility is in use (User Charges) to a waste processing facility. costs and made by an established (user fee). Equity of rates must be care- Charges can be made on a volume or rate schedule. Can also be ad- fully calculated to avoid unfair distribu- weight basis with special charges. justed to reflect decreases or tion of charges. May require close regula- Charges can cover capital, operation increases in cost. Rate schedules tion, particularly for private developer or and maintenance costs. provide a flexible revenue-producing operator. High user fees may redirect wastes mechanism. Can be used by either to other facilities that are less environ- a private or public developer or mentally sound. operator. Methane Decomposing organic material produces Methane gas can be sold if a Must await possible long term Recovery carbon dioxide, methane and other gases sufficient amount is available development of the gas in the by reason of its mutual degradation, and markets are available. fill. May not be of sufficient even when buried. Gas wells are used quality to sell without further to tap and process the methane com- processing equipment. Very market ponent. sensitive. Composting Product produced by the degradation Recyclable product can be sold Limited markets and competition of organic material. to offset processing costs. with other soil supplement products or virgin products (for recyclables). TABLE 54 SOURCES OF GRANTS MECHANISM DESCRIPTION ADVANTAGES DISADVANTAGES Granting Agency 1. United RCRA* and 201** grants to municipal- Hatching grant programs up to RCRA grants not funded. 201 grants limited States ities or other eligible local govern- 85% of eligible costs of con- to construction plus a percentage of costs Environ- ment bodies. Combined with state struction. Higher amounts for planning and design.*** Projects must mental monies. available for innovative score sufficiently high on priority ranking Protection alternatives (75% Federal, which favors water pollution projects. Agency 15% State). 2. United Grant and loan guarantee programs Research monies exist. Municipal programs are not being funded. States for private and public energy-related Programs must be energy related. Department programs. of Energy 3. New York Environmental Quality Bond Act (EQBA) 25% grants from EQBA for EQBA bond money fully committed. New State grant program for local government- landfills only. bond act may provide funds. Must be Department owned projects. approved by voters. of Environ- mental Conservation 4. New York Research grants can apply to public Matching grant programs. Funds limited to research and new energy State Energy and private projects. related projects. Research and Development Authority Resource Conservation and Recovery Act. Section 201 of Federal Clean Water Act. 14.5% for projects of $100,000 or less to 5% for projects up to $200 million, calculated on a downward sliding scale. TABLE 54 SOURCES OF GRANTS MECHANISM DESCRIPTION ADVANTAGES DISADVANTAGES 5. United Has Small Cities and Urban Develop- Solid waste projects are eligible Funds limited, very competitive. Generally States ment Assistant Grants. Grants are for grants. project must be done in conjunction with Department made to municipalities for private other redevelopment projects. of Housing development of local projects. and Urban Development 6. United Farmers Home Administration loan and Loans available for rural portions Eligibility limited to rural projects. States grant programs for rural areas made of a county project. Other sub- Department to local government units. divisions may be eligible for loans W co of in areas with less than 10,000 Agriculture population. 7. United Grants ranging from 50 to 80% of Direct grants to publicly-owned Grants based on job creation. Generally States costs through Economic Development facilities. Grants based on total small projects, $400,000 to $1 million. Department Administration (EDA) to municipali- project costs. No solid waste projects to date. Limited of Commerce ties for public projects. to publicly owned projects. SECTION 7. RECOHMENDATIONS Long Term Recommendations for Regionwide Sludge and Septage Management Septage Send All Septage to Designated Sewage Treatment Plants (STPs) 1. Select sewage treatment plants (STPs) to receive septage based on: a. transportation distance b. existing sludge holding capacity C. size of facility d. disposal option used at facility and cost of disposal e. sludge quality at the designated STP. (Sludge must be of acceptable quality. Septage can not be mixed with contaminated sludges.) 2. Provide separate process train for septage at designated STPs consisting of: a. influent structure (mechanical bar screen and grit removal) b. flocculating clarifier or dissolved air flotation C. storage or digestion, depending on disposal alternative. d. utilize disposal options available at the designated STP Sludge* 1. "A" sludges should be land applied whenever possible. 2. For "C" sludges: investigate upgrading sludge quality by: an industrial pretreatment program source reduction of contaminents 3. For "D" sludges: land apply at dedicated site (best alternative) - incinerate - landfill Sludge Quality Evaluation Criteria are contained in Figure 1. 239 Integrated Site one centralized site could be used to implement four options: land application, landfill (for sludge and ash residue), composting, and incineration. The site could be developed on a modular scale to allow ease of expansion, flexibility of operation, and centralized management. A minimum of 200 acres would be required for any of these options. a. Landfill Construct a landfill to handle incinerator ash and as a backup for composting, land application, and incineration shutdowns when and if necessary. b. Incineration Two modular 20 tons per day (TPD) facilities could be constructed initially, capable of expansion. For example, Westchester County's sludge could be sent to this incinerator should ocean disposal be discontinued in the future. C. Composting A ten to 30 dry tons per day aerated static pile composting facility could be constructed if appropriate after on site pilot projects. d. Land Application Sludge could either be applied on site if the site is large enough, or to cropland in the surrounding area. The concept of central site management could be particularly effective because: 1. A central staff could locate and contract for cropland and schedule sludge and compost applications in the seven county area. 2. A staff or contracted agronomist could be available for both land application and composting programs. 3. Central computer data management could be provided. 4. The application of sludge or hauling of sludge and compost could be contracted or done by staff. Ideally, the centralized site should be located close to a wastewater treatment plant. If sufficient land is not available to contain all four opt ions, one or more options might be located away from the main site. For example, farmland for land application might be a short distance away, as might a landfill. 240 General Recommendations by Alternative Land Application Land application is recommended as the preferred alternative as it is the least costly, the simplest, and uses the recycle value of sludge and septage to the maximum. The amount of sludge which may be land applied in the region is limited by its quality and whether it is stabilized in accordance with NYSDEC regulations. As a first step in developing a land application program, sludge and septage quality must be defined to a degree not now available. Section 2 of this report provides a brief discussion of the need for further analysis of sludge quality. With good data on sludge quality, a county or regional management plan could be developed, using private farms on a rotational basis. Table 26 in Section 2 indicates that a significant quantity of sludge and septage (28,000 tons) could be land applied in the region using only about f-ive percent of the region's available cropland. On an individual county bas is, only Westchester and Rockland counties have insufficient land to use this option for a major portion of their sludge and septage wastestreams. Specific Recommendations - Land Application 1. Ini tiate a six month sampling and analysis program, in accordance with NYSDEC guidelines, to adequately characterize sludge quality at sites where such data is currently licking or inconclusive. 2. Discuss with NYSDEC officials the advisability of conducting a sampling and analysis program for domestic septage. 3. Develop appropriate siting criteria and evaluate specific sites within the region to implement a sound management approach for a land application p r o j e c t .Municipalities should be actively involved during the criteria development stage. 4. Where sludge is determined to be "contaminated", an evaluation should be made of the causes. The cost efficiency of addressing the contamination problem at the source versus treating a contaminated sludge should also be investigated. 5. Develop a detailed cost estimate for each generation and disposal site considered for development. 6. Consider canvassing the region for potential "dedicated" sites that could be used for disposal of "D"-rated sludges. 241 Landf ill As discussed in Section 3, landfilling of sludge and septage should be limited to interim measures or cases where no other option is available. The availability of landfill space in a neighboring county is severely restricted by non-importation laws which nearly every county has. Landfilling sludge fails to use the energy and nutrient values of sludge, wastes landfill capacity, and generates a substantial amount of leachate due to the high moisture content (approximately 80 percent). Long term reliance on landfilling should be limited to the following: 1. Sma 11 plants which are located too far from another disposal option to make transportation economical. 2. STPs which produce a "C" or "D"-rated sludge ("contaminated" or "semi-contaminated", respectively) if ocean disposal or incineration options are not available. 3. As a backup for other disposal options, for example when insufficient winter storage is available for sludge which is usually land applied or when an incinerator is out of service and storage capacity is exhausted. Where landfilling of sludge is contemplated, facilities for dewatering to a minimum of 20 percent solids and a stabilization process to significantly reduce pathogens (PSRP) must be available. Composting Composting is not a disposal process, per se, but only a conditioning process to provide an enhanced disposal opportunity for sludge. The principal nutrient in sludge, nitrogen, is reduced by approximately 50 percent during the composting process. The production of compost from sewage sludge and septage is costly. The lack of long term experience with composting operations in the U.S. makes cost estimates for composting imp ossible without completing detailed site and sludge analyses. The major difficulties in developing accurate cost estimates are: - cost and availability of bulking agents - transportation costs for sludge and finished compost - availability of markets for compost and the market value of compost. Despite these disadvantages, EFC encourages the seven counties to implement a c omposting program at least on a pilot scale. Composting can augment any sludge management program, especially on a regional basis, and provide an opportunity to expand a small scale facility should the economics of composting appear favorable. This approach is particularly attractive considering the uncertain future of ocean disposal and EFC's recommendation to discourage landfilling as a sludge disposal option'. 242 Expansion of a composting facility could be phased in together with the pha sing out of either a landfill or ocean disposal. In addition, uncertain future regulatory constraints regarding incineration (especially air pollution control and ash disposal considera tions) as well as the cost of this option make composting worth the investment on a small scale. EFC recommends: 1. Develop an aerated static pile pilot project on a site with adequate buffer and expansion area. 2. Mon itor closely the success of new in-vessel composting systems in the east (including in Schenectady, Plattsburgh, and Endicott in New York State and Cape May, New Jersey) for application to the seven county region. Five small-scale composting facilities, some privately operated, currently exist d% in the region. These should be investigated for their potential to be upgraded for county or regionwide participation. Ocean Disposal Although sludge and septage is disposed of in the ocean directly from only one STP (Yonkers) septage haulers and other STPs in the region use the ocean,. mostly for indirect disposal of septage. While the quantities of septage contributed from outside Westchester County are not significant (approximately 1,500 dry tons per year), the elimination of ocean disposal as an alternative would have a significant effect on the indirect users of ocean disposal. Given the uncertain future of ocean disposal beyond 1991, it would be irresponsible to recommend that this option be considered by communities not now employing it. Based on a favorable bid by a private contractor, Westchester County has, understandably, elected to continue ocean dispQsing of sludge until such time as this practice is prohibited by the USEPA. The potential for upstate counties to take advantage of ocean disposal was considered at meetings with county technical representatives and is addressed in Section 3 of this report. The constraints of time and cost did not permit EFC to do a detailed evaluation of the expansion or construction of suitable docking facilities and the necessary appurtenances required to implement an ocean disposal program for facilities north of Westchester County. However, USEPA officials indicated in discussions with EFC that they would be receptive to an application for interim permission to ocean dispose of sludge from upstate sources, either alone or in concert with Westchester County. As discussed in Section 3, Ocean Disposal, such a permit application would be costly to prepare and implement and, perhaps, be only a short term option. However, owing to the low overall disposal cost to Westchester ($109 per dry ton), this option may be a viable alternative to other options based on cost and availability. 243. Incineration Incineration is the recommended alternative: I for the disposal of "C" contaminated sludges, since these sludges may not be composted or land applied 2. for the disposal of "D" (semi-contaminated) sludges where a dedicated disposal site is not available for land disposal or landfill options. Incineration processes should only be considered by STPs larger than five mil lion gallons per day, and at locations where landfill or ocean disposal of sludges is limited or prohibited by regulatory agencies. The existing incinerators in. the counties should upgrade dewatering facilities and combustion control equipment to provide more cost effective operation and increased capacity. A modular incinerator should be incorporated in EFC's' recommended integrated regional facility. This will allow the flexibility of treating contaminated sludges and will provide a backup alternative for treatment of land disposed, uncontaminated sludges during winter months. The modular concept will allow for expansion of the incinerator facilities should the results of the recommended further analysis of sludges, indicate a larger amount of "C" sludges, or should sludge quality deteriorate at any treatment plant, in the future. If a regional integrated site is developed and the incinerator alternative is incorporated as recommended, the participating counties must also site a secure ash landfill to dispose of residual ash from the incineration process. The site selection process and evaluation criteria should be developed in accordance with Section 5 (Siting) of this report.. 244 Recommendations for Each County DUTCHESS COUNTY At the time of this writing, the Dutchess County Resource Recovery Facility is approxmately 50 percent complete. The County expects to accept the fac ility from thedeveloper in March of 1987. The opening of this facility should coincide with the closure of virtually all landfills in the county. This situation will create a crisis in sludge and septage management if alternate disposal plans are not prepared. With the exception of approximately 2,300 dry tons of sludge and septage which are composted at one site , nearly all sludge and incinertor ash is ultimately landfilled in the county. With a future of limited landfill capacity available in the county, other sludge and septage disposal options should be considered. A land application program for all sludge and septage generated in the county would require approximately five percent of the cropland available in Dutchess. The availability of two sludge incinerators at Arlington and Beacon, provide the potential to dispose of sludges in the county which do not meet land application and composting standards. Recommendations 1. -Dutchess has the unique opportunity to explore the potential of composting-on a full scale basis due to the existence of a 2,300 tons per year facility in Poughkeepsie. The success of this operation should be monitored by the County or a regional authority, and the potential for expansion to a county-or region-wide program can be explored. 2. EFC recommends a land application program be developed to land apply all sludge and septage meeting NYSDEC quality guidelines. EFC believes that this option is particularly important.in Dutchess because: a. The resource recovery facility will provide an opportunity to phase out all but one landfill in the county for ash and non-recyclables. Thus, no refuse will be available for sludge mixture requirements and landfill space will be particularly valuable. b. The availability of an operating composting facility could provide an opportunity for a "dual utilization" program: composting of sludge during winter months and applying to land when climatic conditions permit. 3. Upgrade the dewatering capabilities and combustion control equipment at the Arlington and Beacon sludge incinerators to provide for more cost effective operation and excess capacity. This excess capacity should then be reserved for "contaminated" sludges which cannot be land applied or composted or to provide a backup for land application and composting programs. 245 ORANGE COUNTY The major sludge disposal option available to Orange County is landfilling at the Orange County Landfill (OCLF). Several small landfills are currently operating on a limited basis and their closure appears to be imminent. In addition to landfilling, several small lagoons and land application operations exist in the county. It is believed that the existing lagoon and land application programs cannot qualify for a permit under NYSDEC regulations and will also be closed in the near future. Orange County presently has no access to ocean disposal, incineration, or composting alternatives in the county. NYSDEC has determined that the OCLF is located above a primary aquifer, and has refused to allow lateral development or expansion of the existing site. A 1986 study by O'Brien and Gere (see "Review of County Reports", Section 3) recommended that retrofitting a liner and leachate collection system would be adequate for protection of the aquifer. Currently, an environmental impact statement is being prepared on the landfill expansion and public hearings are anticipated. NYSDEC denial of permission to expand the OCLF may result in a disposal crisis for all wastes generated in Orange County. Septage management programs at three major treatment plants in the county: Newburgh, Orange County Sewer District No. 1, and New Windsor, are progressing well and it is anticipated that most septage in the county will eventually be handled in this manner. This procedure for managing septage at STPs is consistent with EFCs recommendations. The ultimate disposal of this septage is also at the OCLF. Recommendations 1. Orange County currently relies on the OCLF for 80 percent of its sludge and septage disposal. Tfiis quantity could approach 100 percent in the future when operations which do not qualify for a permit are curtailed by NYSDEC. With this in mind, the County should move to implement alternative sludge and septage disposal options on a county or regional bas is. This approach would be particularly important if plans for the OCLF expansion were denied or limited. 2. Due to the almost total reliance on the OCLF and the uncertain future of that site, Orange County should be especially supportive of the "integrated site" concept discussed in Long Term Recommendations. The integrated site could conceivably provide incineration, composting, and land application options to supplement or replace sole reliance on the OCLF. 246 3. In addition to the integrated site approach, Orange County could consider the following possibilities to reduce its reliance on the OCLF: a.. Land application on a county basis would require 3.2 percent of available cropland for all sludge and septage generated in the county meeting UYSDEC regulations. b. Incineration could be considered at a larger STP to receive sludge not acceptable for land application or composting and as backup capacity for those options. The Newburgh incinerator could be retrofitted with a belt press and combustion control equipment. C. Ocean disposal as a short term option could be discussed with Rockland and Westchester counties As mentioned in Recommendation No. 5 for Rockland County. d. Composting of sludge and refuse (co-composting) was recommended for Orange Co unty in an engineering report reviewed during the course of this study (see Section 3). While EFC does not recommend co-composting at this time, Orange County should consider composting at the OCLF or other appropriate site on a pilot scale should a regional sludge-management approach or an integrated site appear not to be implementable in the near future. 247 PUTNAM COUNTY Putnam disposes of nearly all its sludge and septage out of the county. Three STPs in the county dispose of sludge on site. This practice is probably not permissible under NYSDEC regulations and will be discontinued in the future. Two other STPs dispose of sludge in Dutchess County. The future of this option is questionable when considering Dutchess County's sludge disposal problems. One STP disposes of sludge at the Phillipstown landfill. Phillipstown and Patterson are the only two landfills currently operating in the county. Discussions with technical representatives from Putnam indicate that both of these sites may be closed within a year. The remainder of all sludge and septage generated in Putnam is ocean disposed. Accurate quantities of sludge and septage generated in the county are impossible to determine without a site by site analysis because a large percentage of sludge and septage is being discharged out of the county. Recordkeeping is inadequate at the smaller facilities, and most septage is transported by haulers locate outside of the county. According to a Malcolm-Pirnie report in 1981 4.7 million gallons (588 dry tons at 3 percent solids) of septage are generated annually in the county. Information supplied by county technical representatives led EFC to estimate that approximately 300 tons per year of sludge are generated in addition to septage. As it is estimated that only 13 percent of the Putnam County population is sewered and little attempt is made to determine the origin of septage, the quantities of septage could be much greater than estimated. Putnam County technical representatives have indicated that the plan to modify the Carmel No. 2 STP to receive septage from a large portion of the county has been amended to accept septage from the Town of Carmel only. However, the town has taken no steps to modify the facility to include provision for septage treatment. The information furnished to@ EFC seems to indicate that, in the near future, Putnam will have no viable disposal sites within the county. In addition, EFC is aware of no contractual agreements between the county and other municipalities or private entities, or any impending negotiations in progress or planned, to provide viable disposal options for Putnam. 1 "Septage and Sludge Treatment and Disposal Study for Putnam County, New York", Malcolm-Pirnie, June 1981 248 Although Putnam County generates the least amount of sludge and septage in the region, it has the greatest need to develop a viable sludge and septage management program because: a. Data available on sludge and septage quantities and quality is mostly estimated and of questionable value. b. No acceptable disposal sites in Putnam County may be available beyond next year. C. No k'nown planning efforts are in progress to secure disposal sites in or out of the county. Recommendations 1. Putnam County should act immediately to appoint a waste management task force to stimulate and coordinate efforts within the county to provide for adequate disposal of wastes generated within the countIy. 2. Putnam County should actively support and foster future efforts toward a regional solution to sludge and septage management. 3. The plan to dispose of septage at STPs, as suggested in the Malcolm-Pirnie report, should be seriously considered on a countywide basis. In addition, sludge from smaller STPs lacking dewatering or stabilization processes should also be considered for disposal at the larger STPs. This approach will undoubtedly require expansion of solids handling facilities at most, if not all, facilities designated to receive this additional material. 4. For the short term, the County, by way of a waste management task force or other means, should immediately engage in negotiations with private entities and other municipalities such as, Westchester County, to secure disposatoptions beyond 1986. 249 ROCKLAND COUNTY Due to the lack of potential sites for sludge disposal facilities, Rockland fac es an imminent crisis in sludge management. This is a similar situation to that occurring in Westchester with the exception of Rockland's inability to ocean dispose of sludge. The quality of approximately 90 percent of the sludge generated in Rockland County (i.e. , "contaminated") limits the disposal options This quality restriction limits disposal options to three: ocean disposal, incineration or Vandfill. The landfill situation in the county is essentially limited to the Town of Haverstaw Landfill which will not accept sludge from outside the Town except on a very limited, emergency basis. Incineration is available at the Orangetown STP. Rockland County Sewer District No. I (RCSD#I) is presently hauling sludge to Orangetown and is comtemplating construction of its own incinerator. A delay in the siting and construction process could create a problem as new process units coming on line next year could generate sludge quantities beyond the capacity of the Orangetown incinerator. Ocean disposal facilities are presently not available to Rockland County. Recommendations 1. Sludge quality in Rockland County precludes land application and composting as viable sludge management alternatives. The sources of sludge contamination should be determined. The cost of reducing contaminants in the sludge should be evaluated against the limited availability of disposal alternatives if quality is not improved. 2. If improving sludge quality is not cost effective, RCSD#l should proceed with its plans to build a multiple-hearth incinerator in addition to the following considerations: a. Pursue an agreement with 'the Town of Haverstraw to accept the ash from RCSD#l and Orangetown at the Town landfill in exchange for providing incineration capacity at one or both incinerators for HaVerstraw's sludge. b. Orangetown should consider replacing existing vacuum filter equipment with dewatering equipment capable of producing at least 25 percent solids (belt press). This retrofit should prove to be cost effective and result in additional incinerator capacity. C. The Village of Suffern, which also produces a "contaminated" sludge, should consider joining the RCSD#l and Orangetown incineration plans. The Village's composting facility is operating without a NYSDEC permit and the potential uses of a "contaminated" compost are severely limited. 3. Recommendation 2c for Westcheter County should be implemented in Rockland. 250 4. If a regional integrated site is developed, Rockland County should be involved because: a. Upgraded sludge quality in the county could permit Rockland's participation in any land application or composting program. b. Landfill capacity could,be available for Rockland's incinerator ash as well as to provide a disposal option backup. 5. Roc kland County produces a large quantity of sludge which is precluded from land application or composting, and landfill capacity is severely limited. The discussions initiated by EFC with USEPA in regard to upstate counties participating in a short term ocean disposal program should be continued and expanded to include a joint Rockland-Westchester program. A delay in constructing an incinerator for RCSD#l could have severe consequences in light of the increased sludge generation expected. Plans for a short term ocean disposal program in cooperation with Westchester County could prove beneficial, providing USEPA approval can be obtained. 251 SULLIVAN COUNTY Sullivan relies principally on landfilling to dispose of nearly all sludge generated in the county. This is a problem for several small plants as they have no dewatering process to achieve the 20 percent solids concentration required for landfilling sludge. The closing of the Merion Blue Grass Sod Farm 'severely hampered sludge disposal opportunities for four of the plants lacking dewatering facilities. Sullivan County plans to take whatever steps may be necessary to upgrade the County landfill to comply with current NYSDEC solid waste regulations. This will require leachaLe collection, groundwater monitoring, and a liner system. EFC believes the county landfill has the capacity to mix all sludge generated in the county with refuse coming into the landfill on an annual basis. However, on a day-to-day basis, problems may be encountered in obtaining an adequate mixing ratio. This could be resolved by creating a stockpiling area for dewatered sludge at the landfill or by developing a schedule for receiving sludge at the landfill. Data characterizing sludge quantity and quality in Sullivan County is particularly poor. The total quantity of sludge generated in the county agrees with EFC's projected estimate. However, individual quantities appear to depart substantially from estimated quantities. Only three plants in the county have quality data; two of these three plants have poor quality sludge. Recommendations 1. Sul livan , along with Ulster County, has a high proportion of cropland to sludge and septage generated and appears to have the best opportunity in the region to implement a countywide land application program. As shown in Table 24, land application of all sludge and septage generated in Sullivan wou Id require only 2.6 percent of the cropland available in the county. To further investigate the feasibility of such a program, a concerted effort must be made to adequately characterize sludge quantity and quality in Sullivan County. 2. The County's plan to upgrade the landfill appears to be a good approach as no other opportunities may be available for refuse disposal. EFC recommends that sludge be applied to land and that landfill space be reserved for other, non-recyclable materials. If the landfill site is expandable, the Sullivan County landfill could provide landfill support for the "integrated site" concept discussed in Long Term Recommendations. 3. Smaller plants lacking dewatering and stabilization processes should truck their liquid sludge to the closest plant able to stabilize it for land application, and dewater it, if landfilling is unavoidable. 252 ULSTER COUNTY With the exception of two small composting operations, Ulster presently uses lagoons and STPs to dispose of septage and town landfills to dispose of sludge generated in the county. Plans are to construct a mass burn resource recovery facility for refuse over the next five years and to landfill sludge with the ash from that facility. At this time, sludge will.not to be incinerated with refuse at the Ulster facility. The trend in septage disposal in Ulster is to continue to increase the amount going to STPs until this is the sole method of septage management. This approach is consistent with EFC's recommendations for septage management. Recommendations 1. The County should closely examine its decision not to co-incinerate refuse and sludge. The apparently successful co-incineration program in Glen Cove, New York, is a case where this approach seems to be effective. Incineration of sludge will produce additional energy, will reduce the amount of material going to the ashfill, and will reduce the amount of leachate to be managed and treated at the ashfill. 2. The plan to landfill sludge with ash avoids many of the problems associated with land application and composting: health concerns, public perception, and multiple site management. However, sludge disposal via landfill fails to use the energy and nutrient value inherent in sludge. Ulster should, at least on a small scale, implement a land application or composting program or both so the landfill approach is not without backup. In formation provided by NYS Department of Agriculture and Markets indicates that -approximately 53,000 acres of'cropland are available in Ulster County. At a conservative land application rate of two dry tons per acre, only 1.6 percent of this cropland would be required to manage all "clean" sludge generated in the county. The Ulster County technical representative was reluctant to consider a land application program because: a. The available cropland figure may be greatly inflated. b. Cropland in Ulster County is rapidly being converted into residential property. C. Much of the cropland in Ulsteris used to grow food for direct human consumption; this would preclude sludge application on those crops. 253 3. Ulster anticipates that at least four of the existing town landfills will remain operable until the resource recovery facility and ashfill are operational. At the time of this writing, NYSDEC has not indicated its wil lingness to issue consent orders keeping the landfills open. The County should discuss this matter in greater detail with NYSDEC when information concerning the results of groundwater monitoring of the existing landfills are available. 254 WESTCHESTER COUNTY Westchester presently uses both the lowest level technofogy (ocean disposal) and the highest level (incineration) available for sludge d i s p o s a 1 .Approximately one-third of the sludge generated in the seven county region is barged to sea from the Yonkers sewage treatment plant. The New Rochelle and Ossining treatment plants incinerate sludge on-site. Recommendations 1. While ocean disposal fails to make adequate use of the inherent nutrient or energy value of sludge, this approach appears to offer the most cost effective option ($109/dry ton) as well as the simplest technological approach to sludge disposal--dumping undewatered, unstabilized sludge. As negative environmental effects of ocean disposal at th e 106 mile site have yet to be determined, the county should continue to use this option until prohibited by federal regulations. 2. Bec ause ocean disposal may be a relatively short term option (three to five years), several parallel aproaches to sludge disposal should be developed: a. Consider retrofitting the county's existing mass burn resource recovery facility at Peekskill to co-dispose of sludge. This should be done as a pilot project with facilities for dewatering sludge to at least 25 percent solids by belt press developed at either the Yonkers plant or the Peekskill facility. b. Treatment of the county's entire municipal waste stream, both refuse and sewage sludge, should be considered as part of any plan to expand mass burn facilites. Adequate technology is available to effectively burn sludge with refuse if such a system is properly designed and operated. C. USEPA studies demonstrate that treatment efficiencies in sludge incinerators can be increased by up to 93 percent by retrofitting existing incinerators with combustion control equipment and belt presses for enhanced sludge dewatering. This retrofit approach should be studied by all municipalities operating sludge incinerators in the county. 'Not only would operating costs be drastically reduced, but excess capacity would become available for use by other municipalities within the county or region. d. The county should foster and support any effort toward a regional disposal facility or facilities to have an option for the future should ocean disposal be eventually limited or prohibited. 255 SECTION 8. PUBLIC COMENTS A number of comments on the draft study were received and reviewed by EFC. ,Changes have been made directly to the text to accommodate editorial or strictly technical comments. Comments more conceptual in nature are reprinted here for the reader's information. Co-nters Hudson Valley Regional Council Orange County Ulster County Sullivan County Putnam County NYSDEC Central Office, Albany NYSDEC - Region 3 Henningson, Durham and Richardson COUNTY OF ULSTER BOX 1800 KINGSTON, NEW YORK 12401 N HEALTH DEPARTMENT . . . . . . DEAN N. PALEN, P.E. 300 Flatbush Avenue F Nil Director of Environmental Sanitation Peter D. Corsones, M.D. 914,338-8443 Commissioner of Health 11 E M 0 R A N D U M DATE: October 8, 1986 TO: Terence P. Curran, P.E.,.Executive Director New York State Environmental Facilities Corporation FROM: Dean N. Palen, P.E.. Director of Environmental Sanitation SUBJECT: Study of Sludge Management Alternatives for Seven Counties in the Hudson Valley (Draft 7/31/86) After reviewing the above referenced document, I offer the following comments: 1. That a permanent regi onal sludge management ,task force should be created. 2. That this task force should be a partnership between local government, state government, the State Legislature, the Governor's Office and the private sector. 3. That representation on the task force.should be extended to a wastewater treatment plant operator, d septage hauler, a policy making representative from the New York State . Department of Environmental Conservation, a State Legislative representative, a representative from the Governor's 6ffice and a representative from industry. 4. That better septage/sludge quality data is needed to select disposal methods that will be permitted by the State of New York. 5. That the prdsent regulations and regulatory trends, Section 4, should be updated quarterly. DNP:d cc: file 257 JAMESGORMAN CHAIRMAN co LEON SIEGEL VICE CHAIRMAN PAUL A. ROUIS, JR. COUNTY ADMINISTRATOR SULLIVAN COUNTY BOARD OF SUPERVISORS SULLIVAN COUNTY GOVERNMENT CENTER MONTICELLO, NEWYORK 12701 TEL. 914-794-3000 EXTENsiat4 200 September 30, 1986 Mr. Teron--e P. Curran, P.E. Executive Director New York State Environmental Facilities Corporation 50 Wolf Road Albany, NY 12205 Dear Mr. Curran: Sullivan County held a public hearing on the "Sludge Management Alternatives For the Seven Counties in the Hudson Valley" on September 3, 1986. The County wishes to commend the Environmental Facilities corporation for its work on this project. It is obvious that a great deal of research and time went into the completion of this report. I The County concurswith the New York State Environmental Facilities corporation and the majority of its findings. It is essential that counties determine the quality of sludge generated so that plans can be more narrowly focused as to how to dispose of this waste. Municipal and private sewage treatment plant operators should be strongly encouraged to undertake sludge quality testing programs. Municipalities should also be encouraged to make provisions to accept septage waste from private home systems. The concept of a centrally locat-ed integrated site is also favored by Sullivan County. Such a site can dispose of sludge through various means. Finally, Sullivan County believes it is important for the Department of Environmental Conservation (DEC) to clearly state its position in regard to the land spreading of sludge. It was recomffiended that.Sullivan-County land spread the majority of its sludge. This, however,' could be difficult for the County to undertake if the DEC has strict regulations against land spreading on steep slopes. SULLIVAN COUNTY IS AN EOUAL OPPORTUNITY AFFIRMATIVE ACTION EMPLOYER nco Mr. Terence P. Curran, P.E. September 30,1986 Page 2 I hope these comments are of assistance to you as you rewrite the draft study. Thank you for allowing Sullivan county to state its views regarding this study. Very truly yours, David a ma -Chairman Supervisors' Committee on Planning, Economic Development, Public Information and Publicity Diane V. Carlton Senior Land Use Analyst Department of Planning and Economic Development DK/DVC/mtg K uf n-r- 259 PUTNAM COUNTY EXECUTIVE Two County Center Carmel, New York 10512 DAVID D. BRUEN Tel. 914/ 225-3641 County Executive October 9, 1986 Mr. Terence P. Curran, P.E. Executive Director New York State Enviroru-nental Facilities Corporation 50 Wolf Road Albany, New York 12205 SUWECT: Draft Septage/Sludge Report Dear Mr. Curran: As a participating County in the development of the subject report, we have been pleased to cooperate in this attempt to f ind a regional solution to the septage and sludge disposal problem. Having reviewed the draft report, we have several comments; some of which are recomended changes which should be included as the draft is revised into a final report. 1. We concur with the management recommendations as set forth in the report. 2. We agree that, the first step in designing sludge handling facilities should be obtaining more accurate data on sludge quantity and quality, however, the below should be considered in this regard. a. Exact quantities will be difficult if not impossible to determine since the majority of sludge is disposed of as septage and sewage treatment plant sludge production records are not readily maintained. The time spent in attempting to gather such data can be better utilized in other areas. It is our opinion that quantity should be estimated based on population. b. Sludge quality should be obtained by sampling sludge at the larger sewage treatment facilities. A size cutoff should be set with all facilities above that* size sampled. Recognizing the difficulty in gaining cooperation on behalf of treatment plant owners, and the need for the analyses on a timely basis, it is suggested that the Counties pay the cost of the analyses. A meeting for all seven counties should be set up with the NYS Department of Environmental Conservation, Solid Waste Division to ascertain the exact sampling requirements, i.e., constituents to be measured and sampling protocols. 3. While we agree that retrofitting existing sewage treatment facilities to allow acceptance of sludge is an alternative we do not feel in reality that such a solution can be implemented due to the poliical complexities involved. We feel that a new regional site is more desirable, and practical. Please contact me if we can be of further assistance. A Very truly your ry truly your vid D. Bruen County Executive DDB:mk ),an Henningson, Durham Suite 212E Telephone: Solid Waste Management/ & Richardson 701 Westchester Avenue (9!4) 328-8505 Resource Recovery Architecture & Engineering, P.C. White Plains, New York Pulp & Paper in Association with 10604-3087 Utilitv & Enerov HDR Techserv. Inc. S_P'ntenber 30, 1986 Terence P. Curran, P.E., Executive Director New York State Environmental Facilities Corporation 50 Wolf Road Albany, New York 12205 Dear Mr. Curran: Our firm has been engaged by several of the counties in the Hudson Valley to assist them in the inplementation of waste-to-energy type resource recovery projects. At least two of these counties are giving serious consideration to coincineration or codisposal of sewage sludge with solid waste. We are therefore concerned that you Ir draft report entitled "Study of Sludge Management Alternative for Seven Counties in the Hudson Valley" seems to present an unduly negative assessment of the potential for coldisposal of sewage sludge with solid wastes. Our studies indicate that the main impediments to codisposal are institutional rather than technological and that from an economic point of view, there appears to be a potential for major savings for communities that are faced-with both a sludge and solid waste disposal problem. We are particularly concerned about your statement on page 204 of HDR your draft report that "NYSDBC is not encouraging applications for codisposal of sludge and, in facti, may not grant permits for codisposal at all in the future". Our discussions with NYSDE)C have led us to believe to the contrary that NYSDBC would be supportive of such applications, provided their legitimate concerns are addressed. Some of our other concems-are summarized in the attached comments. If you have aky questions regarding our concerns, we would be pleased to meet with you at your convenience and provide you with additional data. Sincerely yours, HENNINGSON, DURHM & RICHAMSON AIRCHITBCTURE & ENGINEERING, P.C. In Association with TECHSERVO, INC. o L. Rose, P.E. Assistant Vice President Attachment Y) hn jlr:srw 261 COMMENTS ON OF DRAFT REPCRT STWY OF SLMGE MANAGEMENT ALTERNATIVES The draft report entitled "Study of Sludge Management Alternatives for Seven Counties in the Hudson Valleyn prepared by the New York State Environmental Facilities Corporation and dated July 31j, 1986, contains a number of references to the potential for disposing of sludge together with solid wastes (coincineration or codisposal) which seem to present an unduly negative assessment of the state-of-the-art of the technology of coincineration. The discussion of coincineration as a technical alternative is properly part of the general discussion of thermal reduction processes for sludge disposal. The draft report is correct in stating that "planning and- implementation.... is often hanpered by institutional differences". However, the discussion of the technical approaches does not seem to address the state-of-the-art of codisposal. "Conventional refuse incinerators", which could have problems handling sludge, are not defined. Today's state-of-the--art waste-to-energy plants like the one now operating in Peekskill, Westchester County, can handle significant quantities of dewatered sludge without-significant adverse inpact on conbustion. The key lies in first dewater' the sludge using conventional sludge Ing dewatering techniques such as filter presses to produce a sludge cake with at least 25% dry solids,(less than 75% moisture), and then further drying the sludge before introducing it into the main coubustion chamber. Several systems for this drying process are available commercially, based on operating experience in European plants. Generally, using flue gases as a source of heat and recirculating partially dried sludge seem to have been most successful. As indicated in the report on page 99, "this method has been relatively successful". Corrosion in the dryers can be controlled, in part by the choice of the preliminary dewatering process. Odors can also be controlled by returning all gases that have been in contact with sludge to the main combustion chaniber. The listing of U.S. conincineration facilities in Table 28 is misleading and to some extent out of date. Many of the facilities listed were only pilot or demonstration plants and were never intended for permanent commercial operations. Some were shut down because of their inability to meet current emission standards and not for reasons related to coincineration. The discussion of economic and institutional considerations makes some valid points and some that seem less valid. Citing a 1976 study by Weston, the report states the coincineration had the lowest annualized cost of all combustion technologies, but then warns that the costs still could be prohibitive to many municipalities. This misses the point. If a municipality is contenplating building both a.refuse and a sludge disposal facility?' it is clear that a coincineration facility is more economic than separate facilities., Furthermore, if the costs of the nell 0 coincineration facility are so allocated to refuse and sludge that the refuse tipping fee is held constanto, the cost of sludge disposal is only a fraction of what it would be, if a separate sludge facility had been built. Other allocations are possible so that both the refuse and sludge disposal functions benefit from codisposal. 0 Discussing the institutional factorso, the report correctly concludes that these often serve to discourage combined disposal, particularly when refuse disposal is carried out by the private sector. Howeveri, the recent change in federal tax laws appears to be driving refuse disposal towards the public sector, and the possible availability of state and federal grants could provide a major economic incentive to coincineration. 0 The discussion of the characteristics of the ash residue fails to take into consideration the impact of acid gas emission control devises on residue and leachate composition. In general, such control devices will tend to make the residue and leachate more basic and will thus reduce the concentrations of metals in leachate. Also, USEPA is proposing new tests 0 to evaluate the toxicity of leachate. The tests may make it more difficult to dispose of incineration residues in sanitary landfills although the most recent data shows the actual leachate produced by residue from plants with acid gas controls is relatively benign. The discussion of future NYSDBC policy needs both expansion and 0 clarification. We do not believe that the statement that "NYSDEC is not encouraging applications for co-disposal of sludge andy in facto, may not grant permits for codisposal at all in the future" is a correct statement of current NYSDE)C policy. We are involved in several refuse incineration projects in the Hudson valley area and have discussed the potential for codisposal with NYSDEC for these projects. It is our impression that N!fSDEC would look favorably on permit applications for-codisposalo, provided that the application addresses those issues which are of concern to NYSDBC. It is therefore our opinion that coincineration or codisposal is a very real option for those counties in the Hudson Valley area which have both a sludge and a refuse disposal problem. 263 THE FOLLOWING COMMENTS ARE EXCERPTED FROM A NYSDEC MEMORANDUM TO EFC: Now York State Department of Environmental Conservation MEMORANDUM TOs Ken Malcolm, EFC FROUt Joseph Stockbridge, Residuals Management Sectionj SUBJECT; EFC Lower Hudson Valley Seven County Study DAM October 24, 1986 Integrated Site: One centralized site to implement 4 options: land application, landfill, composting and incinerator for 7 counties may not be cost-effectivedue to the likelyhood of high transportation costs. The concept of centralized or regional management is more important than that of-a single centralized site. General Recommendations by Alternatives Land Application: The number of samples to be taken in 6 month period depends upon the size of each STP. (Details are outlined in the Solid Waste Management Facility Guidelines Section 7.71.1(1)). This proposed sampling program combined with the existing NYSDEC database on sludge quality for Region 3 can provide a good estimate on the quality of sludge generated in this Region. In addition to.the sludge quality, the topographical conditions of the site, the availability of land and the opinion.of the public are among the important factors to ge considered and studied for each county in order to have a successful land application program. Composting: Implementing this option on a limited or pilot scale may not be necessary. Composting should be considered as viable a disposal option as other traditional disposal methods. Public acceptance)odor control and cost-effectiveness may be the most important factors when composting option is considered, not the availability of markets for compost or the market value of compost as suggested. Ocean Disposal: Ocean dumping is primarily chosen because it is a relatively low-cost disposal option. However, a result of the current and projected requirements related to hauling sludge to 106 mile site and permitting and site monitoring will substantially increase the cost of ocean disposal programs. These costs tend to make ocean disposal most feasible for large municipalities only. Incineration: A necessary alternative at this time. Recommended For Each County The recommendations for each county are generally non-specific. It is important to develop specific sludge disposal alternatives for the County's POTW's and Septage Haulers to iWpment. Dutchess County- Since the majority sewage sludges generated by the POTW's within the County are low in concentration of contaminatesbeneficial reuse alternatives should be primarily stressed. An evaluation of the logistics of where the sludge is generated verses where potential landspreading or composting sites are located and potential markets for compost is needed. What sludges are proposed to be dewatered and incinerated at the Arlington or Beacon Incinerators? After the sludge is incinerated where will the ash be disposed? Orange County- The quality of the sludges-generated within the County varies greatly. It is appropriate to diversify in the disposal or reuse alternatives evaluated to allow the maximum flexibility to acceptably handle these differing quality wastes. Since OCLF is looking at a relatively limited site life, it is appropriate at this time for the county to re-evaluate the dewatering and disposal options which may be implemented prior to the closure of the existing landfill. If the Newburgh incinerator is to be re-activated the disposal of the ash should be evaluated. Putnam County- It appears that septage and sludge disposal will not be viable within the county within the relatively near future. Specific alternatives for each of the POTW's and septage haulers needs to-be evaluated. Rockland County Recommendation.#1 is exceptionally appropriate. The POTW's within the-county have a significant problem regarding sludge quality which will constrict the viable alternatives. These alternatives will likely be only incineration and/or landfilling. Siting of these facilities to minimize hauling costs and maximize the countywide use of the facility should be undertaken. Sullivan County Development of specific recommendations for sludge or septage treatment at POTW's within the county is appropriate. The viability.of landapplication of sludge is not known due to a lack of sludge quality data. Until this is rectified landfilling will likely predominate. Ulster County Ditto Sullivan County. Westchester County Development of long-term sludge and septage disposal programs in advance of a disposal crisis is necessary. Since 71% of the County's sludge is presently disposed by Ocean dumping and the long-term viability of this method is uncertain, specific alternatives for disposal of these wastes should be investigated. Conclusion: In general terms, this report identifies several areas which have or will have a disposal site shortage. It also 0 265 identified a lack of substantiated quality and quantity information upon which to undertake alternatives analysis. The report was too generic to allow the counties to implement a specific course of action to resolve the disposal problem without additional facility planning investigations. It is appropriate to proceed to the next step, which would be the development of regional, county or facility recommendations to enable the "disposal crisis" to be resolved. NOTE: These comments are excerpted from a NYSDEC (Albany) Memorandum. 266 DATE GAYLORDINo. 2333 PRINTED IN U.S.A. Li .3 6668 14108 49 38