[Federal Register Volume 64, Number 112 (Friday, June 11, 1999)]
[Notices]
[Pages 31576-31583]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-14770]


-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

[FRL-6357-9]


Voluntary Guide for Industrial Waste Management

AGENCY: Environmental Protection Agency (EPA).

ACTION: Release of draft guidance for public comment.

-----------------------------------------------------------------------

SUMMARY: The EPA, with assistance from State representatives, who serve 
as members of a Task Force from the Association of State and 
Territorial Solid Waste Management Officials (ASTSWMO), industry, and 
public interest stakeholders, has developed a draft voluntary Guide for 
Industrial Waste Management. The purpose of the Guide is to assist 
facility managers, State and Tribal environmental managers, and the 
public in evaluating and choosing protective practices for managing 
non-hazardous industrial waste in new landfills, waste piles, surface 
impoundments, and land application units. The Guide recommends best 
management practices and key factors to take into account in siting, 
operating, designing, monitoring, and performing corrective action and 
closure and post closure care. The Guide is available in both paper 
copy and CD-ROM. The CD-ROM version of the guidance incorporates user-
friendly ground-water and air models to evaluate potential risks and 
choose appropriate facility designs. The Guide is designed to 
complement, not supersede, state and tribal industrial non-hazardous 
waste management programs.
    This guidance reflects four underlying principles: Adopt a multi-
media approach to protect human health and the environment; Tailor 
management practices to risks posed by the waste and the location of 
the unit; Affirm State and Tribal leadership; and Foster a partnership 
among the public, facility managers and regulatory agencies.

DATES: Information and comments must be received on or before December 
13, 1999.

ADDRESSES: Commenters must send an original and two copies of their 
comments referencing docket number F-1999-IDWA-FFFFF to: RCRA Docket

[[Page 31577]]

Information Center, Office of Solid Waste (5305G), U.S. Environmental 
Protection Agency (EPA, HQ), 401 M Street, SW, Washington, DC 20460. 
Hand delivery of comments should be made to the Arlington, VA, address 
below. Comments may also be submitted electronically through the 
Internet to: [email protected]. Comments in electronic format should 
also be identified by the docket number F-1999-IDWA-FFFFF. All 
electronic comments must be submitted as an ASCII file without the use 
of special characters and any form of encryption.
    Commenters should not submit electronically any confidential 
business information (CBI). An original and two copies of CBI must be 
submitted under separate cover to: RCRA CBI Document Control Officer, 
Office of Solid Waste (5305W), US EPA, 401 M Street, SW, Washington, DC 
20460.
    Public comments and supporting materials are available for viewing 
in the RCRA Information Center (RIC), located at Crystal Gateway I, 
First Floor, 1235 Jefferson Davis Highway, Arlington, VA. The RIC is 
open from 9 a.m. to 4 p.m., Monday through Friday, excluding Federal 
holidays. To review docket materials, it is recommended that the public 
make an appointment by calling 703-603-9230. The public may copy a 
maximum of 100 pages from any regulatory docket at no charge. 
Additional copies cost $0.15 per page. The index and some supporting 
material are available electronically.
    The Guide is available on the Internet. Follow these instructions 
to access the information electronically.

WWW: http://www.epa.gov/industrialwaste
FTP: ftp.epa.gov
Login: anonymous
Password: your Internet address
Files are located in pub/epaoswer.

    The official record for this action will be kept in paper form. 
Accordingly, EPA will transfer all comments received electronically 
into paper form and place them in the official record, which will also 
include all comments submitted directly in writing.
    EPA responses to comments, whether the comments are written or 
electronic, will be developed during the development of the final 
Guide. EPA will not immediately reply to commenters electronically 
other than to seek clarification of electronic comments that may be 
garbled during transmission or during conversion to paper form, as 
discussed above.

FOR FURTHER INFORMATION CONTACT: For general information and copies of 
the Guide and CD-ROM, contact the RCRA Hotline at 800-424-9346 or TDD 
800-553-7672 (hearing impaired). In Washington, D.C., metropolitan 
area, call 703-412-9810 or TDD 703-412-3323. A limited number of paper 
copies of the Guide and supporting documents (i.e., ground-water and 
air software technical background documents and user manuals) are 
available for distribution. These are available on a first-come first-
serve basis.
    Questions regarding any aspect of the Industrial Waste Guide or the 
CD-ROM may be left on the following voice mail number (703-605-0755.) 
This voice mail box will be checked frequently and answers will be 
provided in a timely manner.
    Questions of a technical or policy nature regarding the Guide or 
CD-ROM may also be directed to the following individuals:

Paul Cassidy (703-308-7281) for questions on siting, protecting surface 
water, designing and installing liners systems, operating, monitoring 
performance, closure and post-closure care and CD-ROM;
John Sager (703-308-7256) for questions on waste characterization, 
protecting groundwater, corrective action and CD-ROM;
Pat Cohn (703-308-8675) for questions on building partnerships, 
integrating pollution prevention, and designing a land application 
program;
Mark Schuknecht (703-308-7494) for questions on designing a land 
application program only; and
Dwight Hlustick (703-308-8647) for questions on protecting air quality 
only.

    Technical questions or information regarding the ground-water 
software and supporting materials may be directed to Virginia Colten-
Bradley (703-308-8613).
    Technical questions or information regarding the air software and 
supporting materials may be directed to Charlotte Bertrand (703-308-
9053).
    Questions for these individuals can also be e-mailed to their e-
mail address:

[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected]
[email protected].

SUPPLEMENTARY INFORMATION:

Customer Service

    How can I influence the development of the final Guide? In 
developing the draft Guide and CD-ROM, we have tried to address issues 
that are of interest to stakeholders. Your comments will improve this 
Guide and CD-ROM. We invite you to provide different views, new 
approaches, new data, or other relevant information on any aspect of 
the draft Guide or draft CD-ROM. We have developed specific questions 
(See Section II. Request for Comments: Questions and Issues) that are 
included in this Supplementary Information Section. Your comments will 
be most effective if you follow the suggestions below:

Explain your views as clearly as possible and why you feel that way;
Provide solid technical data to support your views;
Tell us which parts you support, as well as those you disagree with;
Provide specific examples to illustrate your concerns;
Offer specific alternatives; and
Refer your comments to specific sections of the Guide, e.g., page 12 of 
Chapter 5, or to specific screen numbers of the CD-ROM, e.g., CA__010.

Outline

I. Background and Overview
    A. Setting the context
    B. The Scope
    C. Underlying principles
    D. Using the guidance
    E. Next steps
II. Request for comments: questions and issues.
    A. Overview
    B. Getting Started
    Chapter 1. Building Partnerships
    Chapter 3. Integrating Pollution Prevention
    Chapter 4. Considering the Site
    C. Protecting Air Quality
    Chapter 5 Protecting Air Quality
    D. Protecting Ground-Water
    Chapter 7a. Assessing Ground-Water Risks
    Chapter 7b. Designing and Installing Liners
    Chapter 7c. Designing a Land Application Program
    E. Ensuring Long Term Protection
    Chapter 9. Monitoring Performance
    Chapter 11. Performing Closure and Post Closure

I. Background and Overview

A. Setting the Context

    About 7.6 billion tons of industrial waste are generated and 
managed on-site at manufacturing facilities each year. Of this, almost 
97 percent is waste water managed in surface impoundments, with the 
remaining more concentrated solids being managed in landfills, waste 
piles, and land application units. These wastes come from the broad 
spectrum of

[[Page 31578]]

American industries and are neither municipal wastes nor hazardous 
wastes under federal or state laws. State and tribal governments have 
regulatory responsibility for ensuring proper management of these 
wastes in on-site units, and their programs vary considerably.
    EPA and 12 state representatives selected from the membership of 
the Association of State and Territorial Solid Waste Management 
Officials (ASTSWMO) began development of this guidance in 1996 with the 
formation of a State/EPA Steering Committee. The goals of the Steering 
Committee were threefold: first, to define a baseline of protective 
management practices; second, to complement existing state and tribal 
regulatory programs; and third to produce an effective and user 
friendly Guide that all stakeholders will use. The Steering Committee 
is co-chaired by one EPA and one state member. At the same time, the 
Steering Committee had the benefit of a Focus Group of industry and 
public interest stakeholders, chartered under the Federal Advisory 
Committee Act, to provide advice throughout development of the 
guidance. Steering Committee and Focus Group members are listed in 
Appendix I at the end of this notice.
    The draft Guide reflects the results of this productive 
consultative process. Focus Group members provided extensive comment 
and commitment of their time throughout. Their thoughtful input helped 
to make the draft guidance a better and more effective product, 
although the final decisions are those of the Steering Committee.
    All material that was part of the development of this draft Guide 
is contained in the public docket and is available for viewing. This 
material includes previous drafts of issue papers, meeting notes, and 
materials submitted by the Steering Committee and the Focus Group.

B. The Scope

    This guidance is useful for a broad array of industrial process 
wastes, especially those that are managed at the facilities where they 
are generated. We did not consider certain extractive wastes, such as 
those from mining or oil and gas production, and recommendations may 
not be suitable for these wastes. Furthermore, any facilities that 
receive municipal solid waste, as well as industrial waste, are subject 
to municipal landfill criteria, 40 CFR part 258, and state or tribal 
municipal landfill regulations. They are not addressed by this 
guidance.
    The guidance focuses, in particular, on the design of new units. 
Liner design and siting concerns are clearly directed at new units. 
However, other management recommendations, such as for ground-water 
monitoring, operating practices, and closure and post-closure care, may 
be helpful in making management decisions for currently-operating units 
as well.

C. Underlying Principles

    This guidance reflects four underlying principles:
    Protect human health and the environment. This is the focal point. 
The guidance is multi-media, emphasizing surface water, ground water, 
and air protection, with a comprehensive framework of technologies and 
practices that make up a sound waste management system.
    Tailor management practices to risks. There is enormous diversity 
in the nature of industrial wastes and the environmental settings where 
they are managed. The guidance provides conservative national 
management recommendations and user-friendly modeling tools to make 
location-specific adjustments. It also identifies complex analytic 
tools to conduct comprehensive site-specific analyses.
    Affirm State and Tribal leadership. States, tribes, and some local 
governments have primary responsibility for adopting and implementing 
programs to ensure proper management of industrial waste. It is 
important to note that individual states or tribes may have more 
stringent or extensive regulatory requirements based on local or 
regional conditions or policy considerations. This Guide complements, 
but does not supersede regulatory programs. It can help you make 
decisions on meeting requirements and filling potential gaps. Facility 
managers and the public using this Guide should consult with your 
regulatory agency throughout the process to understand its regulations 
and how the agency wants you to use the Guide.
    Foster a partnership. The public, facility managers and regulatory 
agencies share a common interest in preserving quality neighborhoods, 
protecting the environment and public health, and enhancing the 
economic well-being of the community. This Guide provides a common 
technical framework to facilitate discussion. Stakeholders are 
encouraged to stay involved and work together to achieve meaningful 
environmental results.

D. Using the Guidance

    There are a few key steps to follow:
    Understand and comply with all existing Federal, State or Tribal 
regulations, permits and operating agreements that apply to a waste 
management unit. The guidance is designed to complement existing 
requirements, not to take their place.
    Thoroughly characterize constituents and concentrations in the 
waste. Waste characterization is the foundation for choosing and 
implementing tailored, protective management practices. To assess 
potential ground-water risks, the guidance provides drinking water 
maximum contaminant levels (MCLs), when they exist, and health-based 
reference levels for 191 constituents. To assess potential air risks, 
the guidance provides inhalation health-based reference levels for 95 
volatile and semi-volatile constituents.
    Take advantage of pollution prevention, recycling and treatment 
opportunities. Pollution prevention, recycling, and treatment can 
minimize reliance on waste disposal, reduce disposal costs and reduce 
future costs and liabilities for closure and post-closure care and 
corrective action. Pollution prevention and recycling also conserve raw 
materials.
    Build a partnership between all stakeholders who have an interest 
in waste management decisions. Keep stakeholders informed and involved 
on an ongoing basis.
    Tailor management practices to the wastes and the environmental 
setting of the unit. The Guide covers all the components of a sound 
waste management system. It recommends best management practices and 
the key factors to take into account in siting, operation, design, 
monitoring, corrective action, closure and post closure care. The 
guidance also directs you to a wide variety of useful tools and 
resources, and includes a number of these tools in appendices. In 
particular, the guidance recommends risk-based approaches and 
incorporates models to choose liner systems and waste application rates 
for ground-water protection and to evaluate the need to control 
volatile organic air emissions.
    Here is an example of how the risk-based evaluation would work for 
choosing a liner system design. For ground water, the approach is 
three-tiered, relying on modeling fate and transport of constituents 
through subsurface soils to ground water. Successive tiers in the 
analysis incorporate more site-specific data to tailor protective 
management practices to your particular circumstances. The CD-ROM 
version of the guidance contains ground-water software for Tier 1 and 2 
analyses.
    Tier 1--National Evaluation: Once you know the concentrations of

[[Page 31579]]

constituents in the waste leachate, the Guide provides generic 
recommendations on appropriate liner design. If leachate from wastes 
going into a unit contains several constituents, choose the most 
protective liner design indicated for any of the constituents.
    Tier 2--Location Adjusted Evaluation: To obtain a recommendation 
that more closely reflects your site, use location-specific data for up 
to seven of the most sensitive waste-and site-specific variables to 
assess whether a particular liner design will be protective.
    Tier 3--Comprehensive Site Assessment: This tier relies on a 
comprehensive analysis of specific waste and site characteristics to 
assess whether a particular liner design will be protective. The 
guidance identifies a number of models for this detailed analysis.

E. What Comes Next?

    The draft guidance is available in a paper copy, on a CD-ROM, and 
through the Internet at www.epa.gov/industrialwaste. EPA and the state 
participants from ASTSWMO welcome your comments on all aspects of this 
draft including the substantive recommendations and the practicality 
and user friendliness of the risk-based modeling tools. Section II of 
this notice frames a number of questions and issues. Based on your 
comments, we will make revisions and release a final version of this 
draft Guide.
    EPA and state representatives participating in this effort believe 
that the recommendations in the final Guide will help to improve 
management of industrial waste at facilities across the country. EPA 
and ASTSWMO will widely disseminate the final Guide and explain the 
rationale behind the recommendations to regulators, industries and the 
public to foster understanding and to encourage stakeholders to 
integrate final recommendations in future industrial non-hazardous 
waste planning throughout the country.
    The Guide is designed for users with different levels of technical 
knowledge and experience in environmental fields. Because many of the 
recommendations address complex and highly technical practices and 
engineered systems, we urge users to seek out technical experts and 
resources to assist in detailed planning, design and implementation.
    We recognize that facility managers, regulatory agency staff and 
the public all have a different role in ensuring protective waste 
management. Building an effective partnership between all stakeholders 
can facilitate sound decisions that protect human health and the 
environment and make common sense for individual facilities.
    Facility managers: The Guide can help you make the decisions 
necessary to ensure environmentally responsible unit siting, design, 
and operation in partnership with State and tribal regulators and the 
public.
    State and tribal regulators: The Guide provides a handy 
implementation reference that complements your program.
    The public: The Guide can help you be an informed and knowledgeable 
partner in addressing industrial waste management issues in your 
community.

II. Request for Comments: Questions and Issues

A. Overview

    Our objectives throughout development of this draft Guide have been 
to provide protective, substantive recommendations, informative 
discussion of each topic, and references and tools that help users 
proceed to a more in-depth study and review of each topic. We have 
attempted to make the guidance easy-to-use, accessible and meaningful 
to users with a wide range of experience and different levels of 
technical knowledge. However, we recognize that individual topics are 
addressed at varying levels of detail. We have developed a series of 
questions for most chapters of the Guide. We have also highlighted some 
general questions regarding the Guide and CD-ROM. We invite comments on 
all aspects of the Guide and CD-ROM, including the following questions.

     Are the recommendations appropriate, realistic, and 
protective?
     Does the Guide meet the needs of small businesses?
     Does the Guide meet the needs of the interested public?
     Does the coverage for each topic provide the right 
level of detail? What could be added, subtracted or handled 
differently to make each topic more useful?
     Is the Guide organized to provide quick access to the 
information you are seeking?
     Are there other references and sources of information 
that should be cited in the guidance or included on the CD-ROM?
     For the CD-ROM, does the software work well? Do the 
interactive portions of the CD-ROM present useful information? Is 
the CD-ROM organized well?
     For the ground-water and air models, do the individual 
models work well? Are the models easy to use and understandable? 
(See sections below for further discussion of issues associated with 
each model.)

B. Getting Started

    Chapter 1. Building Partnerships: We recognize that the process of 
building successful partnerships between regulators, industry, and the 
public can be contentious.

     Would it be helpful in the final guidance to provide 
case studies of successful partnerships? If so, can you provide 
examples of partnerships that have been successful in solving 
problems and addressing specific waste management issues?

    Chapter 3. Integrating Pollution Prevention: The Guide addresses 
pollution prevention, recycling and treatment in abbreviated fashion. 
Because the primary focus of the Guide is waste management, we chose to 
defer to the many excellent resources and materials devoted entirely to 
waste reduction, pollution prevention and treatment rather than attempt 
to cover them comprehensively. In addressing pollution prevention, our 
objectives for this guidance have been two. First, the guidance 
attempts to clearly identify the many linkages between making and 
implementing sound waste management decisions and pollution prevention, 
recycling and treatment options that can reduce waste management costs 
and long term liabilities. Second, we have tried to identify and 
include references that will give you a jump start to the wealth of 
resources that are available.

     Are there other references that will provide users with 
the best points of entry and assistance to address pollution 
prevention, waste reduction, recycling and treatment?
     Recognizing that the primary focus of the guidance is 
waste management, are there additional pollution prevention topics 
that the Guide should cover in more detail, such as, recycled 
product procurement guidelines, beneficial use or reuse of 
materials, or specific pollution prevention activities that overlap 
with waste management activities? Provide us with specific 
information and examples if you can on areas that you believe should 
be included.

    Chapter 4. Considering the Site: This chapter recommends a wide 
variety of data sources to provide information on the geologic and 
hydrologic characteristics of a site.

     Can the existing information systems that integrate a 
wide variety of hydro-geologic information be easily used to make a 
site-specific determination that a planned unit will be sited in an 
acceptable location? If not, would it be helpful for users to be 
able to access one hub that could connect to a variety of data 
sources to evaluate a planned site?
     Alternatively, are determinations relating to wetlands, 
floodplains, fault areas, karst terrain, etc. so site-specific that 
national data bases will not provide sufficiently detailed 
information to help in the evaluation of an individual site?

    As part of EPA's effort to address the siting of industrial waste 
management

[[Page 31580]]

units, the Agency is investigating the potential to develop a tool that 
would allow a user to quickly get an initial determination as to 
whether the unit is located in or close to an undesirable location. The 
EPA is investigating the use of available data from the U.S. Fish and 
Wildlife Services regarding wetlands, the Federal Emergency Management 
Agency regarding floodplains, and the U.S. Geological Survey regarding 
karst and seismic areas and making this information part of the 
Agency's EnviroMapper application. The EnviroMapper application 
provides users with interactive Geographic Information System (GIS) 
functionality using EPA spatial data. EnviroMapper allows users to view 
spatial data at the national, state, and county levels, as well as 
utilize GIS functionality, such as displaying multiple spatial layers, 
zooming, panning, identifying features, and querying single EnviroFacts 
points. EPA is considering the initial development of a GIS protocol 
for one State that would map the location of floodplains, wetlands, and 
seismic and karst locations within the State using the EnviroMapper 
application. We are interested in receiving comments on the utility of 
such a protocol. The Agency is also considering the potential addition 
of cultural (e.g., demographics), administrative (e.g., parks), and 
physical (e.g., pipelines) information to this planned GIS protocol. 
Questions concerning the initial development of the GIS protocol can be 
directed to John Sager whose number was previously listed in an earlier 
part of today's preamble.

C. Protecting Air Quality

    Chapter 5. Protecting Air Quality: The guidance recommends 
assessing human health risks posed by volatile and semi-volatile 
compounds released from waste management units and taking appropriate 
measures to reduce significant risks. Measures to reduce risks include 
implementing pollution prevention or treatment to reduce or eliminate 
VOC concentrations in the waste and implementing controls to reduce 
emissions from the unit.
    1. Assessing Air Risks: The Guide suggests two approaches to 
assessing risk. The first is a limited site-specific air assessment 
using the Industrial Waste Air Model (IWAIR) included in the CD ROM 
version of the guidance. This air model assesses direct risks through 
inhalation of volatile and semi-volatile compounds. The second approach 
is a comprehensive risk assessment that relies on detailed analysis of 
waste-and site-specific data and the use of models designed to assess 
multi-pathway exposures to airborne contaminants. The guidance 
identifies several models for such a detailed analysis.
    IWAIR contains three modeling components. The first is an emissions 
model that estimates emissions of specific constituents from the unit 
into the atmosphere. The second component of the model estimates 
atmospheric dispersion of constituents and ambient air concentrations 
at a specific receptor point. The third component combines constituent 
concentrations at the specified receptor point with receptor exposure 
factors and toxicity benchmarks to estimate risk.
    Emissions: IWAIR incorporates the emissions model CHEMDAT8. Once a 
user enters data to characterize the unit and the waste, CHEMDAT8 
calculates the emission rate. CHEMDAT8 was developed by EPA and has 
undergone extensive review. IWAIR allows a user to enter site-specific 
data for unit and waste characteristics or to rely on default data to 
calculate emissions.
    Dispersion: The dispersion model used in IWAIR is EPA's model 
Industrial Source Complex Short Term Version 3 (ISCST3). ISCST3 is a 
complex model and running it to develop a new dispersion factor for 
each site and waste management unit requires extensive meteorological 
data and technical expertise. In order to create an easily accessible 
and user-friendly modeling tool to evaluate the dispersion of air 
emissions, ISCST3 was previously run to generate a database of 
dispersion factors. The dispersion factors are included in IWAIR and 
have been calculated for many separate scenarios designed to cover a 
broad range of unit characteristics. There is a dispersion factor for 
each combination of:

--29 meteorological stations, chosen to represent the nine general 
climate regions of the continental U.S.;
--4 unit types;
--14 surface area sizes for landfills, land application units and 
surface impoundments, and seven surface area sizes and 2 heights for 
waste piles;
--6 receptor distances downwind from the unit out to a maximum of 1000 
meters; and
--16 directions in relation to the center point of the unit.

    The default dispersion factors were derived by modeling each of 
these scenarios. When IWAIR is run, the maximum dispersion factor, at a 
distance selected by the user for a specific waste management unit 
size, is used for the computations.
    The advantage of this approach to dispersion modeling is that IWAIR 
provides you with a quick, easy-to-use method to calculate dispersion. 
Relying directly on ISCST3 requires significant technical expertise, 
access to a very complex and resource-intensive model, and substantial 
amounts of data. On the other hand, a limitation of the IWAIR model is 
the fact that it does not reflect the exact conditions of a specific 
location.
    Risk model: This component of IWAIR combines the constituent-
specific emission rate with the dispersion factor to calculate a VOC's 
concentration in the air at a specified receptor location. IWAIR 
calculates adult-worker or resident exposures based on inhalation, body 
weight, exposure duration and frequency, and ambient concentrations of 
constituents at a specific receptor location. Default values for these 
parameters are based on EPA's Exposure Factors Handbook. IWAIR relies 
on standard health benchmarks (cancer slope factors for carcinogens and 
reference concentrations for non-carcinogens) to calculate risk or 
acceptable waste constituent concentrations.
    IWAIR can be used two ways. Forward calculation uses known 
constituent concentrations in a waste to calculate risk to receptors at 
specified locations. Backward calculation starts with a target risk 
level at a specified receptor location. The model then calculates the 
concentration levels in a waste that can be protectively managed in a 
unit without exceeding a pre-selected target risk level.
    The Air Model User's Manual and Background Document contain 
detailed discussion on all components of the model. We invite comments 
on all aspects of the model, the values and data sources used to 
characterize specific parameters, and the modeling approach, including 
the following questions.

     Is the modeling approach that relies on matching 
limited site specific information to previously calculated 
dispersion factors a reasonable method to estimate dispersion of 
constituents from a unit? Are there refinements to this approach 
that could improve site-specific calculations and still be 
incorporated into a similar user-friendly and accessible model?
     Are the assumptions built into various components of 
the model reflective of the range of unit characteristics and 
conditions encountered in real situations?

    We are also obtaining peer review of IWAIR by a group of technical 
experts who have been commissioned to provide an independent analysis 
of the model and the way it is used in the

[[Page 31581]]

guidance. The results of the peer review will be noticed in the Federal 
Register, as soon as they are available, so that interested parties may 
obtain copies for review.
    2. Controls:
     Are there other control techniques or technologies that 
are effective in minimizing the release of particulates or VOCs from 
waste management units besides those discussed in Chapter 5 of the 
Guide? (While the Guide addresses VOC's through modeling, best 
management practices are identified as appropriate activities for 
addressing particulates from these units.)

D. Protecting Ground Water

    Chapter 7. Protecting Ground Water: The guidance recommends 
tailoring protective liner systems to the wastes that are managed in a 
unit and evaluating whether land application of a waste is appropriate 
using a three-tiered approach to ground-water modeling and risk 
assessment. The type of assessment you choose depends, in part, on the 
complexity of a site and the characteristics of the waste. All three 
rely on ground-water modeling to evaluate the potential for ground-
water contamination. Each successive tier incorporates more site-
specific data to tailor recommendations to your circumstances.
    The modeling tool for Tiers 1 and 2 is the EPA Industrial Waste 
Evaluation Model (IWEM) incorporated into the CD ROM version of this 
guidance. This is a stand-alone, simple-to-use model that does not 
require previous modeling experience. Tier 1 tables are also in the 
paper-copy version of the guidance.
    Tier 1--National Evaluation: Once you know the expected leachate 
concentrations of constituents in a waste, generic design 
recommendations (e.g., liner system or whether land application is 
appropriate) are provided. This tier of analysis uses a summary of site 
conditions that exist across the country.
    Tier 2--Location-Adjusted Evaluation: You can enter data for up to 
seven of the most sensitive waste-and site-specific variables to assess 
whether an alternative design will be protective.
    Tier 3--Comprehensive Risk Assessment: This tier relies on a 
comprehensive analysis of all waste and site characteristics to assess 
whether an alternative design will be protective.
    Chapter 7a. Assessing Risk: IWEM analyzes different liner scenarios 
over a 10,000 year time frame. Tier 1 and 2 risk evaluations work as 
follows. IWEM can evaluate 191 constituents with toxicity reference 
levels that are either drinking water maximum contaminant levels (MCLs) 
set under the Safe Drinking Water Act or health-based numbers (HBNs) 
derived from several sources. In addition, the model allows a user to 
add additional chemicals for analysis and to adjust MCLs and HBNs to 
reflect state-specified or other values.
    First, IWEM identifies a benchmark concentration (MCL or HBN) for 
each constituent in a receptor well associated with a waste management 
unit. The goal is not to exceed the benchmark concentrations in the 
receptor well (defined as a monitoring well). The model starts from 
this benchmark concentration in the receptor well and uses the effects 
of dilution and attenuation and leakage rate from a unit to determine 
the leachate concentration threshold values for wastes that can be 
protectively managed in a particular unit design. In a similar fashion, 
the model determines leachate concentration threshold values for wastes 
that are being considered for land application.
    Leachate concentration threshold values for constituents are based 
on toxicity reference levels, with two exceptions. First, the 39 
hazardous waste toxicity characteristic (TC) constituents are capped at 
their TC levels, because concentrations above those levels would cause 
the waste to be regulated as a hazardous waste and thus outside the 
scope of this Guide. Second, the model caps each leachate concentration 
threshold value at 1000 mg/l, because we do not expect constituent 
concentrations in leachates exceeding 1000 mg/l to be released from 
industrial waste management units.
    The IWEM Technical Background Document accompanying the model 
thoroughly explains the model, including the parameters that have the 
greatest effect on modeling results. The parameters that a user can 
input are:

     Infiltration rate from the unit;
     Surface area of the waste management unit;
     Depth to water table;
     Distance to the well;
     Thickness of the aquifer;
     Retardation rate; and
     Degradation rate.

    One of the most sensitive parameters is the infiltration rate or 
the rate at which leachate is released from a unit and moves into 
subsurface soils. The infiltration rate is influenced by a number of 
factors, including the amount of precipitation, the level of liquid in 
the unit (head), and the hydraulic conductivity of the liner material. 
For synthetic liners, the occurrence of tears, rips or holes also 
influences the infiltration rate.
    Units that rely only on natural soils underlying the unit, 
including units for direct land application of waste, generally have 
higher leakage rates. A single clay or synthetic liner can reduce the 
leakage rate to some extent. However, composite and double liners that 
combine two or more layers of liner material with leachate collection 
and leak detection (for double liners) significantly increase the 
effectiveness of the containment system in minimizing leakage to the 
subsurface during the period when the leachate collection system is 
actively managed.
    For a landfill that no longer receives waste and for surface 
impoundments and waste piles where waste remains in place at closure, 
the cap that is placed over the unit becomes an important component of 
the final containment system. One key purpose of the final cap is to 
minimize the infiltration of precipitation into a closed unit. 
Precipitation generates leachate that may eventually migrate into 
subsurface soils and to ground water. The liner system in the short 
term, and the cap and the liner system together in the long term, to a 
large extent determine the infiltration rate from the unit. The 
infiltration rate that is associated with various unit designs is one 
of the most sensitive variables in evaluating the degree of 
protectiveness provided by a particular liner system.
    The Guide recommends a comprehensive approach to design, 
construction, operation and long term care of a waste management unit 
to minimize the potential for problems affecting liner performance . 
This includes:

     Recommending a liner design, taking into account the 
characteristics of the waste managed in the unit;
     Emphasizing construction quality assurance and control;
     Emphasizing compatibility between the liner and the 
waste;
     Continuing operation and maintenance practices to 
protect liner performance;
     Ground-water monitoring, to assess liner performance, 
as an integral component of a protective management system;
     Closing the unit with a cap that meets or exceeds the 
design of the liner (infiltration through the cap equal to or less 
than leakage through the liner); and
     Post-closure care and monitoring to maintain the cap 
for the time period necessary to ensure the waste no longer poses a 
risk to human health.

    Assumptions concerning liner performance have a significant impact 
on the modeling results. A brief summary of the modeling scenarios for 
each liner type follows (the model currently assumes that performance

[[Page 31582]]

levels remain constant for the 10,000 year time frame of the modeling 
effort).
    No liner: This is a waste management unit that sits in direct 
contact with native soil. Monte Carlo analysis of a range of 
infiltration rates is based on water balance and native soil type for 
97 meteorological stations. In Tier 2, the model can provide a regional 
infiltration rate based on a user-specified location.
    Single liner: This consists of three feet of compacted clay with a 
hydraulic conductivity of 10-7 cm/sec. Monte Carlo analysis 
of a range of infiltration rates is based on water balance for 97 
meteorological stations. In Tier 2, the model can provide users with a 
regional infiltration rate based on a user-specified location.
    Composite liner: This is an engineered system that consists of 
three feet of compacted clay and a synthetic liner. The system is 
assumed to include a leachate collection system that maintains a 
hydraulic head of no more than 12 inches for landfills and waste piles. 
The leakage rate is a single value calculated using an equation, 
developed by Giroud and Bonaparte, based on one 0.005 in.2 
hole per acre. For landfills, the calculated leakage rate is 0.1 
gallon/acre/day and for surface impoundments the calculated leakage 
rate is 0.9 gallon/acre/day. This would represent a high performing 
liner. The assumptions regarding the composite liner leakage rate are 
discussed in the IWEM Technical Background Document.
    In general, we have learned much over the past 20 years about the 
performance of liner systems and caps, and there have been many 
improvements in construction, installation, and quality assurance and 
control procedures. However, we recognize that there is still 
uncertainty associated with liner performance, both in the near term as 
well as in the long term. While some studies indicate that engineering 
properties of liners may last for many (perhaps several hundred) years, 
there are a variety of factors that may influence longevity and 
performance, such as poor construction, installation or facility 
operation, or geologic movement below the liner that can cause holes, 
tears or larger failures. Some defects are likely to have little to 
moderate effect on the leakage rate. Other defects may have a 
significant effect and may even necessitate corrective action.
    We have conducted some preliminary sensitivity analyses to compare 
infiltration rates from a variety of theoretical composite liner 
scenarios. Scenarios varied the size of holes and tears; the number per 
acre; contact between the geomembrane and the clay layer; the 
conductivity of the underlying clay layer, and the head of liquid on 
top of the geomembrane. Results of these preliminary analyses provided 
a range of infiltration rates ranging from well below to well above the 
infiltration rate of 3.3E-05 meters/year used in the Tier 1 analysis 
for landfills. These results indicate several key areas in which EPA, 
the Steering Committee, and the Focus Group could conduct additional 
evaluations to evaluate liner effectiveness more thoroughly:

     What empirical data are available concerning liner 
defects at the time of installation and over time to serve as a 
basis for identifying reasonable performance scenarios?
     What are reasonable methods for estimating leakage? 
Some estimation methods may be reasonable within specific bounds or 
time frames for various performance scenarios, but may not work for 
a wide range of performance scenarios or time frames.
     If we were to conduct a Monte Carlo analysis of leakage 
rates for composite liners, what is a reasonable range to include in 
the analysis?
     How should we account for degradation of the liner 
system over time? (A more thorough discussion of the sensitivity 
analyses is in the IWEM Technical Background Document.)

    Another area of uncertainty is the fate of constituents within a 
unit. Over time, a number of degradation processes may be under way 
that reduce the hazards associated with some constituents. On the other 
hand, a landfill with an intact cover may be reasonably dry, reducing 
leachate generation, but also slowing down degradation. Other toxic 
constituents, such as heavy metals, can not degrade.
    Covers present continuing engineering challenges over time, because 
they are more susceptible to factors such as freezing and thawing, 
wetting and drying, temperature fluctuations, root infiltration, and 
subsidence. Covers are, however, not subject to chemical attack from 
waste constituents, nor are they subject to the same stresses from 
waste placement as a bottom liner. Also, final covers are simpler to 
repair, which would help control the risk of infiltration into the 
landfill, assuming there is an active program to monitor or 
periodically replace the cover. Unless the final cover is regularly 
repaired or replaced, the bottom liner could outlast the cover. While 
covers containing a synthetic membrane are likely to prevent 
precipitation from entering a closed unit during the period that they 
are performing as designed and assuming there are no failures, 
uncorrected failure of a cover would allow precipitation to enter the 
unit. After leachate removal is discontinued, this could lead to a 
``bathtub effect,'' where the unit has increasing leachate volumes and 
hydraulic head that could lead to increased leakage rates or overflow.
    We invite comments on all aspects of the model, the values, and 
data sources used for specific parameters, and the modeling scenarios 
for liner performance, including the following questions.

     Is the cap of 1000 mg/l concentration for constituents 
in leachate from a non-hazardous industrial waste management unit 
realistic? If not, please provide data on which waste units may 
generate leachate that contains constituents at higher concentration 
levels and what those levels and constituents are likely to be.
     What performance assumptions, modeling approaches and 
design scenarios are reasonable to address the question of the 
changing effectiveness of liners and caps over time?
     Can you provide data on the occurrence of defects in 
liners at the time of installation and on changes in leakage rates 
or indicators of possible changes in liner defects that occur over 
time?
     The hazardous waste program deals with uncertainties 
associated with liner and cap performance by requiring treatment 
prior to disposal. How should such uncertainties be dealt with for 
non-hazardous industrial wastes? One possibility is to rely on 
quality assurance and quality control, long-term ground-water 
monitoring, and corrective action to address non-hazardous waste 
management units. Where uncertainties are too great, EPA could elect 
to rely on the hazardous waste program to list such wastes as 
hazardous and require treatment. A second approach could be to rely 
on treatment of certain non-hazardous wastes. What other approaches 
are available? Please provide any expressions of support for or 
concerns about any of these approaches.
     Should the composite liner scenario use a different 
infiltration rate, or Monte Carlo analysis to reflect a range of 
performance levels, rather than the single value currently used in 
our Tier 1 analysis? What values should be used, and what is the 
basis for using them? The IWEM Technical Background Document 
presents the range of infiltration rates used in the Tier 2 analysis 
and discusses the limitations of the Tier 2 modeling results if one 
were to use infiltration rates outside the modeled range of 
infiltration rates.

    We are also obtaining peer review of the ground-water model by a 
group of technical experts who have been commissioned to provide an 
independent analysis of the model and the way it is used in the 
guidance. The results of the peer review will be noticed in the Federal 
Register as soon as they are available so that interested parties may 
obtain copies for review.
    In Chapter 7a of the Guide, EPA makes reference to an alternative 
Tier 2

[[Page 31583]]

model developed by the American Petroleum Institute (API). API's 
Graphical Approach for Determining Site-Specific Dilution-Attenuation 
Factors (DAFs) was presented to the Steering Committee and the Focus 
Group during the development of this Guide. API developed this approach 
to simplify calculation of facility-specific DAFs. A copy of API's User 
Manual for this graphical approach has been included on the CD-ROM. EPA 
solicits comment on API's request that this model be incorporated in 
the Guide as an alternative Tier 2 assessment tool.
    Chapter 7b. Designing and Installing Liners and Caps: Construction 
and installation quality assurance and quality control are critical to 
ensuring liner and cap performance. The guidance is intended to reflect 
up-to-date installation practices and techniques and the appropriate 
materials and techniques for installing a liner system and a final cap.

     Are there additional practices and techniques that 
should be reflected in the guidance?
     For those with experience installing liners and 
operating lined units, how do you measure liner performance and what 
are your experiences over time when monitoring and addressing liner 
performance?

    Chapter 7c. Designing a Land Application Program: The Guide 
recommends an evaluation framework for a number of waste and soil 
parameters, in addition to the constituents in Tier 1, that are 
important in designing an effective land application program. The Guide 
discusses the waste and soil parameters and their relationship to the 
establishment of an appropriate application rate as part of an 
effective land application program at a unit.

     Are there models or other tools available to simplify 
design and evaluation of a land application program?

E. Ensuring Long Term Protection

    Chapter 9. Monitoring Performance: The Guide urges a multi-media 
approach to protective waste management. While the Monitoring 
Performance chapter briefly addresses monitoring other environmental 
media such as air, soil, and surface water, the chapter is devoted 
primarily to ground-water monitoring.
    Should the guidance expand discussion and recommendations 
concerning monitoring other environmental media, and if so, how?
    Chapter 11. Performing Closure and Post Closure Care: As discussed 
above under Protecting Ground Water: Assessing Risk, proper closure and 
post closure care are critical elements of a program that ensures long 
term protection.

     Please comment on factors that should be taken into 
account in determining the time frame for post-closure care and in 
determining when it is appropriate to end post-closure care.
     What experience can you report regarding materials and 
construction techniques for final caps that work particularly well 
or that may pose problems?

    The draft Guide represents a substantial amount of time and effort 
on the part of the Steering Committee and Focus Group representatives. 
EPA believes that the Guide has the potential to be widely used by 
States, industry, and the environmental community based on the 
voluntary nature of the guidance, the multi-media aspects of the Guide, 
and, in EPA's opinion, the quality of the work that will continue 
through the development of the final Guide. EPA looks forward to 
receiving comments on this Guide and working with the Steering 
Committee and the Focus Group as we develop a final Guide for 
industrial non-hazardous solid waste management.

    Dated: May 14, 1999.
Elizabeth Cotsworth,
Acting Director, Office of Solid Waste.

Appendix 1--Current and Past Steering Committee Representatives

James Warner, Minnesota Pollution Control Agency
Anne Dobbs, Texas Natural Resource Conservation Commission
Cyndi Darling, Maine Department of Environmental Protection
Jon Dilliard, Montana Department of Environmental Quality
Richard Hammond, New York State Department of Environmental 
Conservation
Elizabeth Haven, California State Water Resource Control Board
Jim Hull, Missouri Department of Natural Resources
Jim Knudson, Washington State Department of Ecology
Marc Crooks, Washington State Department of Ecology
Chris McGuire, Florida Department of Environmental Protection
Gene Mitchell, Wisconsin Department of Natural Resources
William Pounds, Pennsylvania Department of Environmental Protection
Bijan Sharafkhani, Louisiana Department of Environmental Quality
Kerry Callahan, Association of State and Territorial Solid Waste 
Management Officials
Paula Clark, Maine Department of Environmental Protection
Norm Gumenik, Arizona Department of Environmental Quality
Steve Jenkins, Alabama Department of Environmental Management
Jim North, Arizona Department of Environmental Quality
Robert Dellinger, EPA
Richard Kinch, EPA
Paul Cassidy, EPA
John Sager, EPA
Pat Cohn, EPA
Dwight Hlustick, EPA
Virginia Colten-Bradley, EPA
Charlotte Bertrand, EPA
Mark Schuknecht, EPA

Current and Past Focus Group Representatives

Paul Bork, The Dow Chemical Company
Walter Carey, Nestle, USA, Inc. and New Milford Farms
Rama Chaturvedi, Bethlehem Steel Corporation
H.C. Clark, Rice University
Barbara Dodds, League of Women Voters
Chuck Feerick, Exxon Company, USA
Robert Giraud, Dupont Company
Jonathan Greenberg, Browning-Ferris Industries
John Harney, Citizens Round Table/PURE
Richard Jarman, National Food Processors Association
James Meiers, Indianapolis Power and Light Company
Andrew Miles, The Dexter Corporation
Scott Murto, General Motors and American Foundry Society
James Roewer, Edison Electric Institute
Edward Repa, Environmental Industry Association
Tim Saylor, International Paper
Amy Schaffer, American Forest and Paper Association
Ed Skernolis, WMX Technologies, Inc.
Michael Wach, Western Environmental Law Center
David Wells, University of South Alabama Medical Center
Pat Gwin, Observer from the Cherokee Nation of Oklahoma
Dorris Cellarius, Sierra Club
Brian Forrestal, Laidlaw Waste Systems
Michael Gregory, Arizona Toxics Information and Sierra Club
Gary Robbins, Exxon Company
Kevin Sall, National Paint and Coatings Association
Bruce Steiner, American Iron and Steel
Lisa Williams, Aluminum Association

[FR Doc. 99-14770 Filed 6-10-99; 8:45 am]
BILLING CODE 6560-50-P