[Federal Register Volume 59, Number 175 (Monday, September 12, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-22133]


[[Page Unknown]]

[Federal Register: September 12, 1994]


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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 60

[AD-FRL-5068-3]
RIN 2060-AE94

 

Standards of Performance for New Stationary Sources: Volatile 
Organic Compound (VOC) Emissions From the Synthetic Organic Chemical 
Manufacturing Industry (SOCMI) Wastewater

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule and notice of public hearing.

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SUMMARY: This action proposes standards of performance for wastewater 
sources in the Synthetic Organic Chemical Manufacturing Industry 
(SOCMI). These standards implement section 111 of the Clean Air Act 
(the ACT) and are based on the Administrator's determination that VOC 
emissions from SOCMI cause, or contribute significantly to, air 
pollution that may reasonably be anticipated to endanger public health 
or welfare. The intended effect of these standards is to require all 
new, modified, and reconstructed SOCMI process units to control 
wastewater emissions to the level achievable by the best demonstrated 
system of continuous emission reduction, considering costs, nonair 
quality health, environmental, and energy impacts, not just with end-
of-pipe and add-on controls, but also by eliminating or reducing the 
formation of these pollutants. The proposed regulation would achieve an 
estimated reduction of 16,200 megagrams (Mg) of VOC in the fifth year 
following promulgation.

DATES: Comments. The EPA will accept comments on the proposed rule 
until November 14, 1994.
    Public Hearing. If requested, the EPA will hold a public hearing 
concerning the proposed rule beginning at 10 a.m. on October 12, 1994. 
Persons interested in presenting oral testimony to the EPA at a public 
hearing must contact the person listed below (see FOR FURTHER 
INFORMATION CONTACT) no later than September 27, 1994. Persons 
interested in attending the hearing should call the person listed below 
(see FOR FURTHER INFORMATION CONTACT) to verify that a hearing will be 
held.

ADDRESSES: Comments. Interested parties may submit written comments 
regarding the proposed rule (in duplicate, if possible) to Docket No. 
A-94-32 at the following address: U.S. Environmental Protection, Air 
Docket Section (6102), 401 M Street, SW, Washington, DC 20460. The EPA 
requests that a separate copy of the comments also be sent to the 
contact person listed below (see FOR FURTHER INFORMATION CONTACT).
    Public Hearing. The public hearing will be held at the EPA Office 
of Administration Auditorium, Research Triangle Park, North Carolina.
    Docket. Docket No. A-94-32 contains supporting information used in 
developing the proposed standards. The docket is located at the above 
address in Room M-1500, Waterside Mall (ground floor), and may be 
inspected from 8:30 a.m. to noon, and 1 to 3 p.m., Monday through 
Friday. The proposed regulatory text, Background Information Document, 
and other materials related to this document are available for review 
in the docket. Copies of this information may be obtained by request 
from the Air Docket by calling (202) 260-7548. A reasonable fee may be 
charged for copying docket materials.

FOR FURTHER INFORMATION CONTACT: Mr. Robert Lucas, Office of Air 
Quality Planning and Standards, Chemicals and Petroleum Branch (MD-13), 
U.S. Environmental Protection Agency, Research Triangle Park, North 
Carolina, 27711, telephone (919) 541-0884.

SUPPLEMENTARY INFORMATION: Additional Detailed Information. The 
proposed regulatory text and the Background Information Document are 
not included in this Federal Register document, but are available in 
Docket No. A-94-32 or by request from the Air Docket (see ADDRESSES). 
This notice, the proposed regulatory text, and the background 
information document are also available on the Technology Transfer 
Network (TTN), one of the EPA's electronic bulletin boards. The TTN 
provides information and technology exchange in various areas of air 
pollution control. The service is free, except for the cost of a 
telephone call. Dial (919) 541-5742 for up to a 14,400 bauds per second 
modem. If more information on TTN is needed, call the HELP line at 
(919) 541-5384. A diskette containing the preamble, regulation, and 
background information document will be supplied by faxing the request 
to (919) 540-3470 with name, address, and phone number.
    The following outline is provided to aid in reading the preamble 
for the proposed standards.

I. Introduction
    A. New Source Performance Standards--General
    B. NSPS Decision Scheme
II. Summary of the Proposed NSPS
    A. Source Category to be Regulated
    B. Pollutants to be Regulated
    C. Best Demonstrated Technology
    D. Affected Facility
    E. Emission Points to be Regulated
    F. Format for the Standards
    G. Proposed Standards
    H. Modification and Reconstruction
    I. Compliance Testing
    J. Monitoring Requirements
    K. Reporting and Recordkeeping
III. Impacts of the Proposed NSPS
    A. Environmental Impacts
    B. Cost Impacts
    C. Economic Impacts
IV. Rationale for Proposed Standards
    A. Selection of Source Category
    B. Selection of Emission Sources
    C. Pollutants To Be Regulated
    D. Selection of Affected Facility
    E. Selection of Best Demonstrated Technology
    F. Selection of Format of Proposed Standard
    G. Selection of Standards
    H. Modification and Reconstruction Considerations
    I. Monitoring Requirements
    J. Performance Test Methods
    K. Reporting and Recordkeeping Requirements
    L. Solicitation of Comments
V. Administrative Requirements
    A. Public Hearing
    B. Administrative Designation and Regulatory Analysis
    C. Compliance With Regulatory Flexibility Act
    D. Paperwork Reduction Act

I. Introduction

A. New Source Performance Standards--General

    New source performance standards (NSPS) implement section 111 of 
the Act. The NSPS are issued for categories of sources that cause, or 
contribute significantly to, air pollution that may reasonably be 
anticipated to endanger public health or welfare. They apply to new 
stationary sources of emissions, i.e., sources whose construction, 
reconstruction, or modification begins after a standard for them is 
proposed.
    An NSPS requires these sources to control emissions to the level 
achievable by ``best demonstrated technology,'' or ``BDT.''

B. NSPS Decision Scheme

    An NSPS is the product of a series of decisions made during 
development of the regulation. Elements in this ``decision scheme'' 
include the following:
    1. Source category to be regulated: usually an entire industry, but 
can be a process or group of processes within an industry.
    2. Pollutant(s) to be regulated: the particular substance(s) 
emitted by the source that the standard will control.
    3. Best demonstrated technology: the technology on which the Agency 
will base the standards, as defined in section 111(a)(1) of the Act.
    4. Affected facility: the pieces or groups of equipment that 
comprise the sources to which the standards will apply.
    5. Emission points to be regulated: within the affected facility, 
the specific physical location emitting pollutants (e.g., vents, 
equipment leaks, and wastewater streams).
    6. Format for the standards: the form in which the standards are 
expressed, i.e., as a percent reduction in emissions, as pollutant 
concentration, or as equipment standards.
    7. Standards: based on what BDT can achieve, the maximum 
permissible emissions, or design, equipment, work practice, or 
operational requirements if emission limits are infeasible.
    8. Other considerations: in addition, NSPS usually include 
modification/reconstruction considerations, monitoring requirements, 
performance test methods, and reporting and recordkeeping requirements.

II. Summary of the Proposed NSPS

A. Source Category To Be Regulated

    Volatile organic compound emissions from SOCMI wastewater (also 
referred to as ``secondary sources'') are being regulated under section 
111 of the Act. The proposed standards would regulate VOC emissions 
from wastewater generated by SOCMI process units and are limited to 
emission points in the associated process unit's wastewater collection 
and treatment systems. Specific emission points are discussed in 
section II.E.
    Wastewater is water that comes in contact with process fluids 
during manufacturing, processing, or maintenance operations within a 
process unit at a SOCMI facility. Most wastewaters contain relatively 
low concentrations of contaminants (e.g., less than 2 percent or 20,000 
parts per million (ppm)) and are managed in wastewater collection and 
treatment systems. Wastewater collection and treatment systems 
typically include individual drain systems, oil- water separators, air 
flotation units, equalization tanks, and biological treatments units. 
Volatile organic compounds are emitted from the wastewater during 
collection and treatment.
    Regulations targeting emissions from SOCMI wastewater have been 
developed previously. National emission standards for hazardous air 
pollutants (NESHAP) for benzene waste operations (40 CFR part 61, 
subpart FF) regulate benzene emissions from SOCMI waste streams that 
contain benzene at concentrations of 10 parts per million by weight 
(ppmw) or more at facilities that handle at least 10 Mg/yr of benzene 
in certain wastes. A second regulation, the hazardous organic NESHAP 
(``the HON'') in subpart G of 40 CFR part 63, is broader in scope, 
regulating emissions of many organic hazardous air pollutants (HAP) 
from SOCMI wastewater. The HON imposes standards on SOCMI process 
wastewater streams from process units that produce any of a selected 
group of products at facilities that are major sources under the Act. 
The rule covers individual waste streams that contain one or more of 
the HAP identified in section 112(b) of the Act at concentrations above 
specified levels. Generally, a SOCMI source subject to the benzene 
waste NESHAP would also be subject to the HON.
    A third regulation that may affect the chemical industry is the 
Resource Conservation and Recovery Act (RCRA) air emission standards 
for hazardous waste treatment, storage, and disposal facilities. That 
rule will establish standards for controlling emissions from wastes 
that are identified as hazardous under RCRA at facilities subject to 
subtitle C permitting requirements. Under that rule, hazardous wastes 
would have to be managed in controlled units until the waste is treated 
to remove or destroy certain hazardous components. The rule only 
applies to units and facilities that are permitted under RCRA subtitle 
C. However, under RCRA, wastewater treatment units are not subject to 
subtitle C hazardous waste management standards provided the unit is 
part of a wastewater treatment facility that is subject to regulation 
under either section 402 or 307(b) of the Clean Water Act. Thus, 
hazardous waste tank systems that are used to store or treat wastewater 
that is managed at an on-site wastewater treatment facility with a 
National Pollution Discharge Elimination System permit or that 
discharges to a publicly- owned treatment works would generally be 
exempt from the RCRA regulations.
    In addition to the HON, the benzene waste NESHAP, and the RCRA air 
standards, section 182(b)(2) of the Act requires that State 
implementation plans (SIP's) for certain ozone nonattainment areas be 
revised to require the implementation of reasonably available control 
technology (RACT) for control of VOC emissions. The EPA has defined 
RACT generally as the lowest emission limitation that a particular 
source is capable of meeting by the application of control technology 
that is reasonably available, considering technological and economic 
feasibility. In some cases, the EPA has, or will, issue guidance 
relative to RACT in the form of a control techniques guidelines (CTG) 
document. A draft of the Industrial Wastewater (IWW) CTG was released 
for public comment on December 29, 1993. The SOCMI is a subset of the 
industry group which is covered by the IWW CTG. The CTG is intended to 
provide State and local air pollution authorities with an information 
base for proceeding with their own analysis of RACT to meet statutory 
requirements. Due to time and budget constraints, the IWW CTG has not 
been finalized. An alternative control technology (ACT) document has 
been prepared and provided to the States as interim guidance to aid in 
development of rules in the absence of the final IWW CTG.
    In spite of the guidance and the three separate rules to regulate 
emissions from wastewater streams at SOCMI facilities, there are 
substantial gaps in the extent to which these rules control emissions 
from SOCMI wastewater streams with the potential to emit VOC. The HON 
applies to only a segment of the industry that produces a specified set 
of products, which does not include all SOCMI installations. In 
addition, the HON only regulates streams that contain HAP at 
concentrations above a trigger level. Consequently, the HON does not 
regulate wastewater streams that emit VOC that are not HAP. The benzene 
waste NESHAP applies to all SOCMI installations but is very limited in 
scope regarding the waste streams regulated, i.e., only those streams 
that contain benzene are subject to the rule. Many of the wastewater 
streams at SOCMI plants do not contain benzene but do contain other VOC 
that are emitted to the atmosphere if left uncontrolled. The RCRA air 
standards for hazardous waste toxic storage and disposal facilities are 
not expected to impact a significant number of wastewater streams at 
SOCMI plants because of the wastewater exemption under RCRA that was 
discussed above.
    The EPA analysis of SOCMI wastewater data submitted by industry 
shows a significant number of wastewater streams generated by SOCMI 
process units will not be regulated by the HON or other wastewater 
related rules. This is in large part a result of the fact that the 
source category coverage for the SOCMI Wastewater NSPS is considerably 
broader than that of the HON. For example, the chemical list defining 
the affected SOCMI process units is nearly twice as large for the NSPS 
as for the HON. For many of the SOCMI industries, VOC-containing 
wastewater streams do not contain HAP and therefore controlling only 
HAP-containing streams, as is required under the HON, would not 
substantially reduce VOC emissions. It is estimated that 68 percent of 
all new SOCMI chemical production process units will have wastewater 
streams that would require control under the proposed NSPS but will not 
require control under the HON.
    This NSPS for SOCMI wastewater sources is needed to fill the gaps 
in the coverage of VOC emissions from wastewater streams left uncovered 
by other regulations. In addition, the benzene waste NESHAP and the 
RCRA air standards are risk-based standards. Risk-based standards are 
designed to reduce emissions to a level that will protect human health 
and the environment with an ample margin of safety. The goal of an 
NSPS, on the other hand, is to improve ambient air quality over time by 
application of best demonstrated technology (BDT) on all new, modified, 
or reconstructed sources. The goal of the CTG is to provide guidance to 
States in revising their SIP's and to help bring their nonattainment 
areas into compliance with the National Ambient Air Quality Standards. 
The SIP rules do not apply at facilities that are in ozone attainment 
areas. Furthermore, NSPS require installation of BDT rather than RACT, 
which in some cases may achieve a higher level of emission reduction. 
The NSPS would impose consistent, nationwide regulatory requirements, 
which would ensure that waste streams and wastewater streams at all 
new, modified, and reconstructed SOCMI process units are controlled in 
a consistent manner using the best emission controls.
    In summary, although a portion of waste streams and wastewater 
streams at SOCMI sites are already controlled as a result of existing 
and planned regulations, none of these regulations cover all SOCMI 
waste streams with the potential to emit VOC. These other regulations 
are limited in scope and leave some wastewater streams uncontrolled for 
air emissions. These uncontrolled wastewater streams are the subject of 
the NSPS for SOCMI wastewater sources.
    It is possible that there may be some overlap among those 
regulations affecting wastes and wastewater at SOCMI facilities, 
leading to possibly duplicative requirements. In order to avoid the 
burden of such duplication, the EPA is proposing in the SOCMI NSPS that 
the owner or operator of waste management units, treatment processes, 
or control devices affected by the proposed rule may comply with the 
control requirements of the proposed rule by demonstrating compliance 
with the benzene waste operations NESHAP, the HON, or the RCRA air 
emission standards for hazardous waste treatment, storage, and disposal 
facilities. The owner or operator would also be required to maintain 
records documenting which regulation is being used to demonstrate 
compliance with the proposed NSPS. An owner or operator who chooses to 
demonstrate compliance in this manner would be exempted from the 
inspection, monitoring, reporting, and recordkeeping requirements of 
the proposed rule that relate to the affected waste management unit, 
treatment process, or control device. The Agency is soliciting comments 
on the proposed approach to reducing the regulatory burden for these 
sources. In addition, the Agency is interested in receiving information 
on the level of burden that would be imposed by the possible 
duplication of requirements.

B. Pollutants To Be Regulated

    The air pollutant to be regulated by these standards is VOC. The 
primary air pollutant from SOCMI wastewater facilities is VOC, which is 
a precursor to the formation of ozone and oxygenated organic aerosols.

C. Best Demonstrated Technology

    Section 111 of the Act states that NSPS ``shall reflect the degree 
of emission limitation and the percentage reduction achievable through 
application of the best technological system of continuous emission 
reduction which (taking into consideration the cost of achieving such 
emission reduction, any nonair quality health and environmental impact 
and energy requirements) the Administrator determines has been 
adequately demonstrated.'' The technology basis for NSPS that meets 
these criteria is referred to as ``best demonstrated technology 
(BDT).'' In the standards development process for NSPS, BDT should be 
identified, the performance of BDT established, and a regulatory 
alternative selected that will require the use of BDT or an equivalent 
technology.
    Volatile organic compound emissions from wastewater can be 
effectively reduced with the following control approach: (1) Identify 
wastewater streams with significant VOC emission potential; (2) recycle 
or treat those wastewater streams to remove their potential for 
emissions; (3) prior to treatment or recycling, manage those waste 
streams in units equipped with air emission controls; (4) recycle any 
treatment residuals or treat any residuals to destroy the VOC; and (5) 
control air emissions generated by treatment processes.
    The treatment technology that is the basis for the proposed 
standards for wastewater is steam stripping, a proven treatment 
technology for wastewaters generated within the targeted industry. It 
is generally applicable to wastewater streams with the potential to 
emit VOC and, in general, achieves the highest VOC emission reduction 
among demonstrated VOC control technologies. Facilities can comply by 
installing the design steam stripper or by installing a stripper or 
other treatment device that achieves an equivalent VOC emission 
reduction. Control of air emissions from the stripper and from 
treatment residuals is also required. Although standards for wastewater 
are based on the performance of steam stripping, other treatment 
technologies such as biodegradation have also been demonstrated to be 
effective. To be considered equivalent to steam stripping, a properly 
operated biological treatment unit must achieve a 95-percent VOC 
reduction or meet the required mass removal while controlling air 
emissions. Biodegradation may also be used as one of a series of 
treatment processes (e.g., a steam stripper followed by a biological 
treatment unit) where the combination achieves a reduction of 99 
percent or more in volatile organic concentration. Alternative 
treatment technologies other than biodegradation are permitted if their 
performance equals or exceeds that of steam stripping, i.e., a 99-
percent VOC reduction.

D. Affected Facility

    For the SOCMI wastewater NSPS, the affected facility will be each 
new process unit (and the wastewater streams it generates) at a SOCMI 
plant. A SOCMI process unit will be defined as one producing one or 
more of the chemicals listed in the regulation. A process unit at a 
SOCMI plant will be considered to be new if construction, modification, 
or reconstruction of the unit commences after the date the NSPS is 
proposed in the Federal Register.

E. Emission Points to be Regulated

    The air emission points selected for the proposed regulations 
include all significant points in SOCMI process unit wastewater 
collection and treatment systems that manage process or maintenance 
wastewater streams or residuals generated from SOCMI process units that 
produce any of the listed chemicals. The air emission release points in 
the process unit wastewater collection and treatment system include 
individual drain systems, which are comprised of equipment such as open 
trenches, drains, manholes, junction boxes, lift stations, and weirs; 
surface impoundments; wastewater storage and treatment tanks; oil-water 
separators; containers; clarifiers; and biological treatment units. At 
these release points, VOC can be transferred from the process unit 
wastewater stream to the air.

F. Format for the Standards

    As authorized under section 111 of the Act, the proposed standards 
consist of a combination of emission standards and equipment, design, 
and work practice standards. Emission standards are used whenever 
feasible; however, such standards are not feasible in all 
circumstances. In some cases, alternative emission standards are also 
proposed. Separate standards for tanks, surface impoundments, 
containers, individual drain systems, oil-water separators, treatment 
processes, and control devices are proposed.

G. Proposed Standards

    Under the proposed standards, SOCMI process unit wastewater streams 
with a volatile organic concentration (measured using Reference Method 
25D, 40 CFR part 60, appendix A) greater than or equal to 500 ppmw and 
flow rates greater than or equal to 1.0 liter per minute (Lpm) are 
required to be controlled. In addition, any wastewater stream with a 
volatile organic concentration greater than 10,000 ppmw would be 
controlled under the regulation, regardless of flow rate. Process units 
that generate wastewater with a total annual volatile organic mass of 
less than 1 Mg are exempt from the wastewater control requirements of 
the proposed rule.
    The proposed wastewater treatment standard involves the application 
of a controlled collection and treatment system to individual 
wastewater streams that fail the cut off criteria. The treatment 
requirements are designed to reduce the VOC content in the wastewater 
prior to placement in units without air emission controls. The proposal 
includes a variety of compliance options in order to meet the treatment 
process standard. These include a recycling option involving recycling 
of the wastewater to a process unit, an equipment design and operation 
standard, a numerical emission standard formatted as an effluent 
concentration limit, and a numerical emission standard format in terms 
a mass removal requirement.
    Prior to treatment, the wastewater must be managed in units 
equipped with air emission controls, and wastewater collection and 
treatment systems must be designed and operated without leaks, as 
defined in the standards. Following is a summary of the specific 
standards for each of the individual types of SOCMI wastewater units.
1. Standards for Tanks
    Under the proposed standards, owners and operators would be 
required, with two exceptions, to place wastewater streams in one of 
the following types of tanks depending on the tank capacity and vapor 
pressure of the stored material: (1) A tank equipped with a cover 
(e.g., a fixed roof) and a closed vent system and control device that 
meets certain design, inspection, and measurement specifications 
specified in the rules; (2) a tank equipped with a fixed roof and 
internal floating roof that meets the design requirements specified 
under the existing volatile organic liquid (VOL) storage NSPS (40 CFR 
part 60, subpart Kb); (3) a tank equipped with an external floating 
roof that meets the design, inspection, and measurement requirements 
specified under the existing VOL storage NSPS; or (4) a pressure tank 
that is designed and operated with no pressure releases during normal 
operations including waste loading and unloading.
    The proposed rules would provide two exceptions to the tank control 
requirements described above. First, when an affected stream (i.e., one 
in which the wastewater has a mass-weighted average volatile organic 
concentration equal to or greater than 500 ppmw) is managed in certain 
size tanks and possesses certain vapor pressure characteristics, an 
owner or operator would be allowed to place the waste in a tank 
equipped with a fixed roof. Second, when the waste is placed in a 
biological treatment tank that meets the biological organic degradation 
performance requirements (i.e., 95-percent destruction efficiency), no 
additional air emission controls would be required.
    Each cover opening not vented to a control device would be required 
to be maintained in a closed, sealed position except at those times 
when a specific opening is used to add, remove, inspect, or sample the 
waste in the tank or to inspect, maintain, repair, or replace equipment 
located underneath the cover. Safety devices that vent directly to the 
atmosphere could be used on the cover or closedvent system with control 
device provided that the safety device is not used for planned or 
routine venting of organic vapors and the safety device remains in a 
closed, sealed position at all times except when an unplanned event 
requires the opening of the device.
2. Standards for Surface Impoundments
    The owner or operator of an affected surface impoundment is 
required to install and use emission control equipment. The proposed 
rules would require owners or operators to place waste in a surface 
impoundment equipped with a cover (e.g., air-supported structure) and a 
closed- vent system with control device or, when applicable, a surface 
impoundment equipped with a floating membrane cover as the air emission 
control. If the surface impoundment is used for biological treatment 
that meets the same organic biodegradation performance requirements 
described above for tanks, no additional air emission controls would be 
required to be used on the surface impoundment. The proposed operating 
and venting requirements for surface impoundment air emission control 
equipment are consistent with the rule requirements for tanks.
3. Standards for Containers
    The proposed standards would not apply to a container that has a 
design capacity less than or equal to 0.1 cubic meter (m3) (26.4 
gallons (gal)). The owner or operator of an affected container would be 
required to place the waste material either into a container equipped 
with a cover that operates with no detectable organic emissions when 
all openings are secured in a closed, sealed position or to meet the 
alternative requirements discussed below.
    Alternative requirements under the proposed standards for a drum 
with a design capacity less than or equal to 0.42 m3 (110 gal) 
would allow an owner or operator to place the waste in a drum meeting 
the Department of Transportation (DOT) specifications and testing 
requirements under 49 CFR part 178. For a drum meeting these DOT 
regulations, neither Method 21 of 40 CFR part 60, appendix A, leak 
monitoring, nor recordkeeping of cover design documentation is required 
under the proposed standards.
    Another alternative for containers under the proposed standards 
would require the owner or operator of any container that attaches to 
or forms a part of any truck, trailer, or rail car to show that the 
container has been tested for organic vapor tightness within the 
preceding 12 months in accordance with the requirements of Method 27 of 
40 CFR part 60, appendix A. Method 27 is a pressure test procedure 
originally developed by the EPA for determining the vapor-leak 
tightness of a tank truck into which gasoline is placed. The EPA also 
considers the use of Method 27 to be appropriate for determining vapor-
leak tightness of trucks, trailers, and rail cars into which wastes 
containing volatile organics are placed. Neither Method 21, leak 
monitoring, nor recordkeeping of cover design documentation is required 
for trucks, trailers, or rail cars complying with this provision of the 
rules.
    If a waste is loaded into a container by pumping, the proposed 
standards would require submerged fill of waste only into those 
containers with a capacity equal to or greater than 0.42 m3 (110 
gal). Accordingly, drums with design capacities up to and including 
0.42 m3 (110 gal) are not required to be loaded by submerged fill.
    When it is necessary for a container to be open during certain 
treatment processes, the proposed standards would require the container 
to be located in an enclosure connected to a closed-vent system with 
control device. The enclosure would be required to be designed to 
operate with sufficient airflow into the structure to capture all 
organic vapors vented from the container and route the vapors through 
the closed-vent system to the control device. The enclosure could have 
permanent or temporary openings to allow worker access, passage of 
containers through the enclosure by conveyor or other mechanical means, 
or entry of permanent mechanical or electrical equipment, or to direct 
airflow into the enclosure.
4. Standards for Individual Drain Systems
    The proposed rule would require individual drain systems to meet 
one of two standards. In the first case, the owner or operator would 
comply by operating and maintaining on each opening in the individual 
drain system a cover and closed-vent system. The covers and all 
openings and the closed-vent system would meet the leak detection 
requirements, unless the system is operated and maintained under 
negative pressure. The cover and all openings would be maintained in a 
closed, sealed position at all times when affected wastewater or 
residual is in the system except when it is necessary to use the 
opening for sampling or removal, or for equipment inspection, 
maintenance, or repair. Each individual drain system would be subject 
to initial and semi-annual inspections for improper work practices and 
control equipment failures.
    Alternatively, individual drain system components would be required 
to comply with equipment standards. Each drain would be equipped with 
water seal controls or a tightly sealed cap or plug to eliminate air 
flow through the system. Each junction box would be equipped with a 
cover and emission controls. Each sewer line would be covered or 
enclosed in a manner so as to have no visible gaps or crack in joints, 
seals, or other emission interfaces. This equipment would be subject to 
regular inspection requirements.
5. Standards for Oil-Water Separators
    The proposed standards would require owners or operators to operate 
and maintain either a fixed roof and closed-vent system that routes the 
VOC vapors from the oil-water separator to a control device or a 
floating roof. The fixed roof and all openings and the closed-vent 
system would be maintained in accordance with the leak detection 
requirements of the proposed rule, unless the system is operated and 
maintained under negative pressure. As with standards for other waste 
management units, each opening would be maintained in a closed, sealed 
position except when it is necessary to use the opening for sampling or 
removal, or for equipment inspection, maintenance, or repair.
    Except in cases where it is impossible to operate a floating roof, 
such as over the weir mechanisms, the owner or operator would have the 
option of using a floating roof that meets the requirements of subpart 
QQQ of 40 CFR part 60. The owner or operator would measure primary and 
secondary seal gaps on a periodic basis as well as inspect the oil-
water separator for improper work practices and control equipment 
failures.
6. Standards for Treatment Processes
    The owner or operator would be required to treat each affected 
wastewater or residual stream by one of the following methods:
    (1) Recycle or return to a production process such that the 
wastewater stream or residual is not exposed to the atmosphere and 
ensure that intervening waste management units meet the applicable 
requirements of the standards;
    (2) Treat using a waste management unit that either is a design 
steam stripper, reduces by 99 percent or more the total volatile 
organic mass flow rate, reduces the average volatile organic 
concentration to less than 50 ppmw and reduces the total volatile 
organic mass by 95 percent, or achieves a required volatile organic 
mass removal rate for combined or mixed streams; or
    (3) Treat wastewater streams generated by an affected process unit 
with a biological treatment unit that achieves 95 percent total 
volatile organic mass removal.
    If the treatment process or waste management unit is a properly 
operated biological treatment unit that meets the mass removal (i.e., 
biodegradation) requirements, the biological treatment unit need not be 
covered and vented to a control device. However, the owner or operator 
of any other treatment process or waste management unit subject to the 
applicable standards (for example, if the treatment process is a steam 
stripper, air stripper, or thin-film evaporation unit) would be 
required to cover and vent the unit through a closed-vent system to a 
control device and meet the leak detection requirements, unless the 
cover and vent are operated and maintained under negative pressure. In 
addition, any openings must be kept closed at all times that an 
affected wastewater stream or treatment residual is in the process or 
unit, except during inspection and maintenance and unless the unit is a 
properly operated biological treatment unit as defined by the 
standards.
    Each treatment process or waste management unit used to comply with 
the treatment processes standards would be required to provide a design 
analysis and supporting documentation of the operating characteristics 
of the treatment process or waste management unit that is based on 
operation at a representative wastewater stream flow rate and volatile 
organic concentration under which it would be most difficult to 
demonstrate compliance (i.e., when air emissions are expected to be 
highest). Alternatively, the owner or operator may conduct performance 
tests using the test methods and procedures specified in the proposed 
rules to demonstrate compliance. In addition, all openings are subject 
to periodic inspection and repair schedules and monitoring 
requirements.
    The proposed rule provides several exceptions to the standards for 
treatment processes. The owner or operator is considered to be in 
compliance with the treatment requirements and is exempt from the 
demonstration that the treatment process achieves the required 
conditions if the treatment process is one of the following: (1) A 
hazardous waste incinerator for which the owner or operator has been 
issued a final permit under 40 CFR part 70 and 40 CFR part 264, subpart 
O, or (2) an industrial furnace or boiler burning hazardous waste for 
which the owner or operator has been issued a final permit under 40 CFR 
part 270 and 40 CFR part 266, subpart H or has certified compliance 
with the interim status requirements of 40 CFR part 266, subpart H. In 
addition, if the affected wastewater stream or residual is discharged 
to an underground injection well for which the owner or operator has 
been issued a final permit under 40 CFR part 270 and 40 CFR part 122, 
the owner is considered in compliance with the treatment provisions.
7. Standards for Control Devices
    The proposed standards would require that each control device 
achieve at least a 95-percent reduction in the total organic content of 
the vapor stream vented to the device or, in the case of an enclosed 
combustion device, a reduction of the total organic content of the 
vapor stream to a level less than or equal to 20 ppmw on a dry basis, 
corrected to 3 percent oxygen, or provide a minimum residence time and 
temperature as specified in the proposed standards. Flares would be 
required to comply with the requirements in 40 CFR part 60, subpart A. 
With certain exceptions (e.g., some boilers and process heaters and 
flares), compliance would either be demonstrated through a design 
analysis that addresses vent stream characteristics and control device 
operating parameters or performance tests would be conducted using the 
methods and procedures specified in the proposed rules. In addition, 
each control device is subject to the enhanced monitoring and continued 
compliance requirements of section 114(a) of the CAAA, as well as to 
periodic inspection and specified repair periods.
    The standards would not require the use of any specific type of 
equipment or add-on control device. An owner or operator would be 
allowed the flexibility of choosing the control device that can achieve 
the performance requirements and is best suited for a control 
application based on the types and characteristics of the particular 
organic vapor stream. Furthermore, the standards would not require that 
each affected waste management unit be vented to a separate control 
device dedicated to that particular unit. Vent streams from several 
units can be combined and discharged to a single control device that 
achieves the required level of performance.

H. Modification and Reconstruction

    Provisions of the proposed standards would apply to existing 
facilities that are modified or reconstructed after the date of 
proposal. It is possible that at some facilities, feedstock, catalyst, 
or reactant substitutions; process equipment changes; or combinations 
of these two classes of changes above could trigger the part 60 General 
Provisions related to modification or reconstruction of facilities. 
Changes of this nature are likely to require both equipment and process 
changes as well as significant capital expenditures. See section IV.H 
for a more detailed discussion of these considerations.

I. Compliance Testing

    Test methods and procedures would be required to ensure compliance 
with the standards proposed for SOCMI wastewater sources. The proposed 
standards include requirements for demonstrating that an emission point 
or wastewater stream is being controlled in compliance with control 
requirements or would not be required to be controlled. Also included 
are provisions for an initial test for no detectable emissions (i.e., 
leaks as defined in the standards) from tanks, containers, surface 
impoundments, closed-vent systems, and process wastewater collection 
and treatment systems.
    Test methods are provided for use by the owner or operator in 
determining applicability of the standards to a given wastewater 
stream. The three variables of concern, annual wastewater quantity, 
average total volatile organic concentration, and annual average 
wastewater flow rate, may be determined using a variety of methods. For 
example, the proposed standards include provisions that would allow a 
SOCMI process unit owner or operator to use either direct measurement 
or knowledge of the wastewater to determine the volatile organic 
concentration of the wastewater. Direct measurements would be conducted 
in accordance with the requirements of Method 25D in appendix A of 40 
CFR part 60. Knowledge of the wastewater can be demonstrated by 
material balances, records of chemical purchases, process 
stoichiometry, or previous test results.
    A determination of the volatile organic concentration or average 
annual flow rate of a wastewater would be required by the proposed 
standards only when a wastewater subject to the standards is placed in 
a waste management unit that is not equipped with air emission controls 
in accordance with the rules. The SOCMI process unit owner or operator 
would not be required to determine the volatile organic concentration 
or average annual flow rate of wastewater streams that are managed only 
in units equipped with air emission controls in accordance with the 
requirements of the proposed standard up to the point of ultimate 
recycle, disposal, or discharge.

J. Monitoring Requirements

    To ensure that emission control equipment is properly operated and 
maintained, the proposed standards would require the owner or operator 
to inspect and monitor certain air emission control equipment used to 
comply with the rules. Enhanced monitoring of control device operation 
is required under the proposed standards to demonstrate compliance with 
the standards. This involves the use of automated instrumentation to 
measure critical operating parameters that indicate whether the control 
device is operating correctly or is malfunctioning. Failure to maintain 
the established values of the monitored parameters would be an 
enforceable violation of the emission limits of the standard.
    In addition to the enhanced monitoring requirements, an initial 
leak detection test using Method 21 under appendix A of 40 CFR part 60 
is required for certain cover components to ensure gaskets and seals 
are in good condition and for closed-vent systems to ensure all 
fittings remain leak-tight. The Method 21 test would be supplemented by 
annual visual inspections for leaking components as well as periodic 
inspection and measurement of other monitoring parameters.
    Special inspection and monitoring provisions are included in the 
proposed standards for cover fittings that monitor. Leak monitoring 
using Method 21 is not required for the following: (1) Drums that meet 
applicable DOT regulations specified in the rules; (2) trucks, 
trailers, and rail cars that are annually demonstrated to be vapor 
tight by Method 27 in appendix A of 40 CFR part 60; and (3) closed-vent 
systems operated under vacuum conditions.

K. Reporting and Recordkeeping

    The proposed standards require the owner or operator to record 
certain information in the on-site facility operating logs or files. 
The information to be collected and recorded includes: the results of 
all waste determinations such as volatile organic concentration at the 
point of waste generation and organic vapor pressure; design 
specifications for closed-vent systems and control devices and control 
equipment; emission control equipment inspection and monitoring 
results; Method 21 and Method 27 test results; control device 
monitoring results; leak repairs; identification of incinerators, 
boilers, or industrial furnaces in which wastewater is treated in 
accordance with the general requirements of the rule; documentation for 
biological wastewater treatment units complying with the rule; and 
identification of equipment designated as unsafe or difficult to 
monitor or inspect. This information is to be readily available for 
review by authorized representatives of the EPA. The EPA seeks comment 
on the accessibility of the monitoring data and periodic reports that 
may be kept in logs on the plant site when it is not required to be 
reported to the appropriate agency. These data and reports should be 
accessible to citizen groups that contemplate citizen suits or other 
members of the public interested in the source's compliance status. 
This access is required by section 114(c) of the Clean Air Act as 
Amended (CAAA). Means of providing that accessibility include: direct 
inspection of the logs or files on-site with authority to access the 
data equal to that of the EPA, submission of a Freedom of Information 
Act (FOIA) request to the EPA with an affirmative duty on the part of 
the EPA or the state/local delegated agent to obtain any data from the 
source that the agency does not have in its files, submission of a 
FOIA-like request to the source owner/operator with an obligation on 
the part of the owner/operator to provide the requested data, or a 
requirement to keep electronic files/logs which would be accessible 
through EPA electronic bulletin boards. Other suggestions for meeting 
the mandates of section 114 are welcome.
    The General Provisions of 40 CFR part 60 require the owner or 
operator to submit certain notifications and reports to the 
Administrator. Section 60.7(a)(1) of the General Provisions requires a 
notification of the date construction or reconstruction of an affected 
facility is commenced; the proposed rule requires that certain general 
information regarding the wastewater generated by the source be 
submitted with this notification. Section 60.7(a)(3) of the General 
Provisions requires a notification of the actual date of initial 
startup of an affected facility; the proposed rule requires that the 
owner or operator provide with this notification more detailed 
information and data on the wastewater streams generated by the 
affected process unit. This information includes a determination of 
whether the stream is an affected wastewater stream, the compliance 
approach utilized if the stream is being controlled in accordance with 
the requirements of Sec. 60.109(b) of the proposed rule, the 
identification of the waste management units receiving or managing each 
affected wastewater stream, and certain information on the treatment 
processes and control devices used to comply with the rule.
    Section 60.7(c) of the General Provisions requires that each owner 
or operator required to install a continuous monitoring system (CMS) or 
monitoring device submit an excess emissions and monitoring systems 
performance report and/or a summary report to the Administrator on a 
quarterly basis when the CMS data are to be used directly for 
compliance determination, as is the case for control devices in this 
proposed rule. In order to be consistent with the reporting 
requirements of the HON, which also regulates this industry, the EPA is 
exempting the owner or operator from the quarterly reporting 
requirement and is requiring only a semiannual report in the proposed 
rule. The semiannual report will contain information on the excursions 
or exceedances as determined by the CMS data, performance test results, 
and other information on treatment processes and control devices.

III. Impacts of the Proposed NSPS

    To estimate the impacts of the proposed regulation, the EPA 
estimates the quantity of VOC that the affected industry would emit to 
the atmosphere in the absence of the rule. This estimated quantity 
serves as a baseline from which the impacts of the rule are measured. 
Following estimation of the baseline level of emissions, the Agency 
estimates the emission reduction that would occur as a result of the 
regulatory alternatives for the rule. Studies are then made to estimate 
the impacts of the rule on the environment, the economics of the 
industry and the nation, and on energy consumption. Collectively, these 
estimates represent the impacts of the standard. Estimated impacts 
include emission reductions, costs, impacts on non-air environmental 
media, and energy usage. The impacts presented here are those estimated 
to occur in the fifth year after promulgation.
    All of the impacts are calculated as an increment relative to the 
impacts of the wastewater rules included in the HON. Additional details 
of the impacts analysis can be found in the BID and from documentation 
developed in support of the HON.

A. Environmental Impacts

    Under the proposed NSPS, it is estimated that 68 percent of all new 
SOCMI chemical production process units would have wastewater streams 
that require control under the NSPS but do not require control under 
the HON. It is further estimated that the total annual emission 
reduction achieved by the NSPS in the fifth year would be approximately 
16,200 megagrams per year (Mg/yr) of VOC. Because the NSPS requires the 
treatment of wastewater prior to discharge, there would be no negative 
impacts on water quality. In fact, the impacts of the rule on water 
quality could be positive. Impacts of the rule on solid waste are 
estimated to be negligible.
    Other environmental impacts of the rule are estimated to be small. 
Due to the increased energy requirements of control, emissions of 
carbon monoxide are estimated to increase by about 4 Mg/yr and 
emissions of nitrogen oxides are estimated to increase by about 35 Mg/
yr. Energy impacts of the proposed rule include the combustion of 
fossil fuels to generate steam for steam stripping systems. These 
impacts are partially offset by the recovery of organics from the 
treatment system. Estimated energy impacts of the proposed rule in the 
fifth year consist of an increase of 0.6 million kilowatt hours per 
year (Kw-hr/yr) of electricity usage, an increase in natural gas 
consumption of 133 million British thermal units per year (Btu/yr), and 
an increase in steam usage of 133 billion Btu/yr.

B. Cost Impacts

    The fifth-year cost impacts of the proposed standard are considered 
to be reasonable. Total annualized cost of the rule in the fifth year, 
on a nationwide basis, is estimated at $8.8 million. This results in a 
cost effectiveness of about $540 per Mg of emission reduction. The 
fifth-year national capital cost is estimated at approximately $5.8 
million. The estimated cost impacts assume that most of the regulated 
SOCMI plants with affected process units have an existing steam 
stripping system with sufficient excess capacity to treat the 
wastewater streams regulated under the NSPS or will be able to modify 
steam stripping systems that are currently being designed and 
constructed for compliance with other regulations (e.g., the HON) to 
add sufficient capacity to treat the wastewater streams covered by the 
proposed NSPS that do not require control under these other 
regulations. The estimate also assumes that a small number (about 12 
percent) do not have an existing steam stripper and will have to 
install a new system. These assumptions reflect the Agency's best 
estimate of the way the industry will comply with the rule.

C. Economic Impacts

    The proposed rule is not expected to pose significant adverse 
economic impacts. The impact estimates are also produced assuming the 
costs of control are passed on to the consumer, as is the case in 
competitive markets in the long run. The EPA estimates, on average, a 
maximum price increase of less than 1 percent for SOCMI chemicals. This 
assumes the entire mix of chemicals produced by an affected SOCMI 
facility are proportionately affected by the NSPS, and assumes that the 
chemicals produced at those SOCMI facilities in the EPA database are 
reasonably representative of the mix of chemicals in the industry. The 
market price impacts of specific chemicals may be greater than the 
average presented above. This may be especially true for affected 
chemicals produced in low volumes and affected chemicals that have 
lower-than-average market prices. Chemicals with lower-than-average 
prices could experience higher-than-average control costs per unit of 
revenue. Due to economies of scale in pollution control, affected 
chemicals that are produced in low volumes are likely to have a higher-
than-average cost of control per unit of production. The feature of the 
proposed rule that exempts low volume wastewater streams from selected 
process units may mitigate the price impact of low production volume 
chemicals that produce low volume waste streams. Finally, there will be 
no adverse effects on industry employment or expansion because the 
proposed standards will not appreciably affect the demand for chemicals 
covered by these standards.

IV. Rationale for Proposed Standards

A. Selection of Source Category

    Under section 111(b)(1)(A) of the Act, the Administrator is 
required to publish, and periodically update, a list of source 
categories that in his or her judgement cause, or contribute 
significantly to, air pollution which may reasonably be anticipated to 
endanger public health or welfare. This list appears in 40 CFR 60.16 
and ranks, in order of priority for standards development, various 
source categories in terms of quantities of nationwide pollutant 
emission, the mobility and competitive nature of each source category, 
and the extent to which each pollutant endangers public health and 
welfare. The priority list reflects the Administrator's determination 
that emissions from the listed source categories contribute 
significantly to air pollution that may reasonably be anticipated to 
endanger public health or welfare, and it is intended to identify major 
source categories for which standards of performance are to be 
promulgated.
    The priority list ranks the SOCMI source category first out of 59 
listed source categories. For regulatory purposes, the SOCMI category 
was divided into the following segments: SOCMI unit processes; volatile 
organic liquid (VOL) storage vessels and handling equipment; SOCMI 
fugitive sources; and SOCMI wastewater sources. Standards have been 
developed for the other three groups of SOCMI sources; the NSPS 
proposes standards for the fourth and final category of SOCMI sources.
    This division of the source category on the basis of similar types 
of emission sources and applicable emission control techniques was 
chosen over a more traditional approach for NSPS that involves the 
development of standards applicable to each specific chemical process. 
The selected approach is more resource efficient than the chemical 
process approach because a large number of specific chemical processes 
can be covered by one regulation. In addition, SOCMI plants contain 
similar wastewater emission sources. Similarities in the behavior of 
wastewater emission sources in SOCMI allow the same control techniques 
to be applied to all of the processes. Therefore, because the control 
techniques can be applied to the entire industry group and because 
regulating the entire group would be more resource efficient, a single 
regulation is being proposed for controlling wastewater emissions from 
the SOCMI source category.
    The SOCMI is a large and diverse industry producing several 
thousand intermediate and end-product chemicals from a small number of 
basic chemicals. Most of the chemicals produced by this industry fall 
under standard industrial classification code 286.
    In the proposed rule, a SOCMI process unit is defined as one 
producing or using one or more of the chemicals listed in the 
regulation. The list of chemicals proposed is an inclusive list that 
was derived from several sources that also formed the basis for the 
initial list of chemicals used to characterize SOCMI process units in 
the HON (see appendix A of the HON BID, EPA-453/D-92-016). The 
following sources are the basis for the composite list of chemicals for 
the proposed NSPS: (1) ``Industrial Organic Chemical Use Trees,'' EPA/
ORD, October 1992; (2) Standards of Performance for Equipment Leaks of 
VOC in SOCMI, 40 CFR part 60, subpart VV; (3) Proposed Standards of 
Performance for SOCMI Reactor Processes, 55 FR 26953, June 29, 1990; 
(4) Standards of Performance for SOCMI Distillation Operations, 40 CFR 
part 60, subpart NNN; and (5) Standards of Performance for SOCMI Air 
Oxidation Processes, 40 CFR part 60, subpart III. Therefore, the 
proposed list is a compilation of all the chemicals in these databases 
used to characterize the SOCMI process units.

B. Selection of Emission Sources

    There are several emission sources associated with SOCMI processes 
(e.g., process vents, product storage and transfer operations, and 
equipment leaks); however, this NSPS is directed toward the control of 
VOC emissions from wastewater generated by SOCMI process units. This 
includes emissions from wastewater collection and treatment operations. 
Wastewater streams that contain organic compounds are generated at 
SOCMI process units by one of two mechanisms, either direct contact of 
water with organic compounds or by contamination of indirect contact 
water through equipment leaks in chemical processing.
    Water may come in direct contact with organic compounds during a 
variety of different chemical processing steps, thus generating 
wastewater streams (referred to as ``process wastewater'') that must be 
discharged for treatment or disposal. Direct contact wastewater 
includes water used to wash impurities from organic compound products 
or reactants, water used to cool or quench organic compound vapor 
streams, condensed steam from jet educator systems pulling vacuum on 
vessels containing organic compounds, water from raw material and 
product storage tanks, water used as a carrier for catalysts and 
neutralizing agents (e.g., caustic solutions), and water formed as a 
byproduct during chemical reactions. Direct contact wastewater is also 
generated within SOCMI process units when water is used in equipment 
washes and spill cleanups; this wastewater (referred to as 
``maintenance wastewater'') is typically more variable in flow rate and 
concentration than process wastewater streams and may be collected in 
ways that differ from process wastewater.
    Indirect contact wastewater streams are generated by unintentional 
contact with organic compounds through leaks in process equipment. For 
example, indirect contact wastewater may be generated as a result of 
leaks from heat exchangers, condensers, or pumps. These wastewaters 
also may be collected and treated differently from direct contact 
wastewaters.
    In both the SOCMI NSPS and the HON, ``wastewater'' is defined to 
encompass both process wastewaters and maintenance wastewaters. 
Examples of process wastewater streams include, but are not limited to, 
wastewater streams exiting process unit equipment (e.g., decanter 
water, such as condensed steam used in the process), product tank 
drawdown, feed tank drawdown, filter-press filtrate, and residuals 
recovered from waste management units. Examples of maintenance 
wastewater streams, which encompass all maintenance-related wastewater 
streams, are those generated by descaling of heat exchanger tubing 
bundles, cleaning of distillation traps, and draining of pumps into an 
individual drain system. However, the regulatory approach taken in the 
SOCMI NSPS is different from the one taken in the final HON. The 
proposed SOCMI wastewater NSPS requires that controls be applied to 
reduce air emissions from both process and maintenance wastewater 
streams from SOCMI process units that produce any of the listed 
chemicals. In the HON, maintenance wastewater is regulated by subpart 
F, and process wastewater is regulated by subpart G. Subpart F, 
Sec. 63.105, requires the source owner or operator to develop a 
startup, shutdown, and malfunction plan which includes a description of 
procedures for managing wastewaters generated during maintenance. In 
the final HON, the facility's plan must include a description of 
procedures that will ensure that all maintenance wastewater is properly 
managed and HAP emissions are controlled. No such plan is required in 
the proposed NSPS.
    The EPA selected the regulatory approach for maintenance wastewater 
as proposed in the NSPS because it was determined through review of the 
industry, which included plant visits to newly constructed SOCMI 
process units, that the technologies available for the collection and 
treatment of these wastewaters have been adequately demonstrated at 
SOCMI plants. The EPA is soliciting comments on the proposed approach 
to regulating SOCMI process unit maintenance wastewaters. The EPA is 
interested in receiving information on why new SOCMI process units 
could not be designed and operated to control air emissions from 
maintenance wastewaters in the same manner as process wastewaters and 
information on the impact the small-quantity cutoff for process units 
and the low-flow exemption for wastewater streams will have on the 
collection and treatment of SOCMI maintenance wastewaters in relation 
to air emission control.
    Wastewater streams at SOCMI plants are collected and treated in a 
variety of ways. Generally, wastewater passes through a series of 
collection and treatment units before being recycled to the facility or 
discharged from the facility. Collection and treatment schemes for 
wastewater are facility specific. The flow rate and organic compound 
composition of wastewater streams at a particular plant are functions 
of the processes used, which in turn influence the sizes and types of 
collection and treatment units. Many of the collection and treatment 
system units are either directly or indirectly open to the atmosphere; 
this atmospheric interface creates a potential for VOC emissions. The 
magnitude of VOC emissions from SOCMI process unit wastewaters is 
dependent on factors such as the physical properties of the pollutants, 
the temperature of the wastewater, and the design of the individual 
collection and treatment unit managing the wastewater. Climatic factors 
such as ambient temperature and wind speed also affect VOC emissions at 
many wastewater collection and treatment units. Potential sources of 
VOC emissions associated with wastewater collection and treatment 
systems include individual drain systems, manholes, junction boxes, 
lift stations, trenches, sumps, weirs, oil-water separators, 
equalization or neutralization basins, clarifiers, aeration basins, 
storage and treatment tanks, surface impoundments, and containers. A 
discussion of each of these emission sources is contained in Chapter 3 
of the BID.

C. Pollutants to be Regulated

    New source performance standards are developed under the authority 
of section 111 of the Act. Section 111 of the Act requires the 
regulation of new and modified sources of criteria pollutants 
(identified under section 110 of the Act) and certain other designated 
pollutants.
    Volatile organic compounds are regulated due to their contribution 
to the formation of ozone in the lower atmosphere. Ozone is a listed 
criteria pollutant. Exposure to ozone has been linked to both health 
and welfare impacts. Health and welfare risks from these include 
impaired respiratory function, eye irritation, deterioration of 
materials such as rubber, and necrosis of plant tissue.
    The potential for VOC emissions from wastewater can be assessed 
based on the characteristics of the wastewater at its point of 
generation. Based on information and data gathered on the concentration 
of organics in SOCMI wastewater streams and on the flow rate of these 
streams, the VOC emissions from SOCMI wastewater streams are considered 
to cause or contribute significantly to air pollution.

D. Selection of Affected Facility

    The choice of the affected facility for an NSPS is based on the 
Agency's interpretation of section 111 of the Act. Under section 111, 
the NSPS must apply to ``new sources''; ``source'' is defined as any 
building, structure, facility, or installation which emits or may emit 
``any air pollutant.'' Most industrial plants, however, consist of 
numerous pieces or groups of equipment which emit air pollutants, and 
which might be viewed as ``sources.'' The EPA uses the term ``affected 
facility'' to designate the equipment, within a particular kind of 
plant, which is chosen as the ``source'' covered by a given standard.
    In choosing the affected facility, the EPA must decide which pieces 
or groups of equipment are the appropriate units for separate emission 
standards in the particular industrial context involved and in light of 
the terms and purpose of section 111. One major consideration in this 
examination is that the use of a broader definition means that 
replacement equipment is less likely to be regulated under the NSPS; 
if, for example, an entire plant were designated as the affected 
facility, no part of the plant would be covered by the standard unless 
the plant as a whole were ``modified.'' Because the purpose of section 
111 is to minimize emissions by the application of the best 
demonstrated control technology (considering cost, other health and 
environmental effects, and energy requirements) at all new and modified 
sources, there is a presumption that a narrower designation of the 
affected facility is appropriate. This ensures that new emission 
sources within plants will be brought under the coverage of the 
standards as they are installed. This presumption can be overcome, 
however, if the Agency concludes that the relevant statutory factors 
(technical feasibility, cost, energy, and other environmental impacts) 
point to a broader definition. Another factor considered in the 
selection of an affected facility for the NSPS is the definition used 
in existing environmental rules. The application of these factors is 
discussed below.
    The SOCMI is normally represented as a system of production stages 
that produce a wide range of organic chemicals from a set of 11 basic 
chemicals. The basic set of 11 chemicals is generated by refineries, 
natural gas plants, and coal tar distillation plants. Organic chemicals 
are produced at a wide range of facilities, from large facilities 
manufacturing a few chemicals in large volumes, to smaller facilities 
manufacturing many different finished chemicals in smaller volumes. 
Each of the production stages or ``process units'' may include any of 
several VOC emission sources, one of which is collection and treatment 
of wastewater.
    Three alternatives were considered for defining the affected 
facility in the NSPS. One option considered was to use a variation of 
the definition of source used in the HON, which is ``* * * the set of 
emission points in the organic HAP-emitting processes used to produce 
synthetic organic chemicals that are in a contiguous area under common 
control.'' Under this option of broadly defining the source for the 
NSPS, the affected facility would include all process units and 
associated process unit wastewater streams located at a plant with 
SOCMI process units. A second option considered was the narrow 
definition used in the NSPS for refinery wastewater (40 CFR part 60, 
subpart QQQ), which was ``(1) individual drain systems, (2) oil-water 
separators, and (3) aggregate facilities, which are defined as all 
process drains connected to the first common downstream junction box 
down to the receiving oil-water separator.'' The third and final option 
considered was ``each individual SOCMI process unit'' where each SOCMI 
process unit is defined as the equipment assembled and connected by 
pipes or ducts that use or produce, as intermediates or final products, 
one or more of the chemicals listed in the NSPS applicability section. 
(A process unit can be operated independently if supplied with 
sufficient feed or raw materials and sufficient product storage 
facilities.)
    The broader first option has been used previously by the EPA in an 
existing NESHAP (i.e., the HON) as the source definition for existing 
SOCMI facilities. (Note: Under the HON's new source provisions, new 
SOCMI process units are subject to the rule requirements under a more 
narrow source definition when specified conditions are met.) In that 
regulation, the definition was purposely chosen to be broad to include 
all emission points at any given site under the regulation. As stated 
earlier, a broad definition under an NSPS has a different effect. If an 
entire site is designated as the affected facility for an NSPS, 
existing sources only become subject to the NSPS if the entire site is 
modified or reconstructed.
    Under the second option, each piece of equipment in the wastewater 
collection and treatment system would be considered a unique or 
individual affected facility. This definition, which has a precedent in 
the refinery wastewater NSPS, is much narrower and more restrictive 
than the first option. In general, the narrower the definition of 
source, the more likely it is that changes to existing facilities will 
be deemed ``new sources'' under the Act. This definition would result 
in numerous sources within each SOCMI process unit, as well as numerous 
sources within the wastewater collection and treatment system, being 
classified as affected facilities.
    The third option, that of considering each process unit as an 
affected facility, also has recent precedent. The standards for process 
wastewater components of the proposed pulp and paper rule (58 FR 66077, 
December 17, 1993) are structured such that the process unit is the 
affected facility, and controls are required for wastewater streams 
generated by these units. This approach is also consistent with the one 
taken in the HON for regulation of new SOCMI process units. Defining 
the affected facility on a process unit basis avoids the problems 
associated with having multiple individual collection and treatment 
system equipment components classified as affected facilities, and it 
also provides a definition sufficiently narrow in scope so as not to 
preclude the possibility that existing sources will become subject to 
the NSPS through the modification and reconstruction provisions. Most 
importantly, defining an affected facility as a process unit reflects 
industry construction practices. Almost all new construction, 
reconstruction, and modification in the SOCMI is carried out by process 
unit.
    After carefully considering each of the above alternatives, the EPA 
selected process units as the basis for defining affected facilities 
for the proposed NSPS. This definition allows for routine equipment 
replacement and minor changes or expansions in existing facilities 
without subjecting either single emission sources or entire plant sites 
to requirements of the proposed standards. Providing for full coverage 
of all new process units will improve ambient air quality, the goal of 
standards implemented under section 111.
    Synthetic organic chemical manufacturing industry process units, 
which are defined as the equipment assembled and connected by pipes or 
ducts to process raw materials and to manufacture an intended product, 
include reactors and their associated product separators and recovery 
devices; distillation units and their associated distillate receivers 
and recovery devices; associated unit operations; and any feed, 
intermediate, and product storage vessels, product transfer racks, and 
connected ducts and piping. A synthetic organic chemical manufacturing 
process unit includes pumps, compressors, agitators, pressure relief 
devices, sampling connection systems, open-ended valves or lines, 
valves, connectors, instrumentation systems, and control devices or 
systems.

E. Selection of Best Demonstrated Technology

    Section 111 of the Act states that NSPS ``shall reflect the degree 
of emission limitation and the percentage reduction achievable through 
application of the best technological system of continuous emission 
reduction which (taking into consideration the cost of achieving such 
emission reduction, any nonair quality health and environmental impact 
and energy requirements) the Administrator determines has been 
adequately demonstrated.'' The technological basis for NSPS that meets 
these criteria is referred to as ``best demonstrated technology 
(BDT).'' In the standards development process for NSPS, BDT should be 
identified, the performance of BDT established, and a regulatory 
alternative selected that will require the use of BDT or an equivalent 
technology.
    There are two fundamentally different approaches to controlling VOC 
emissions from SOCMI wastewater sources. The first is a source 
reduction or waste minimization approach in which the emission 
reduction is achieved through a reduction in the quantity of wastewater 
generated and/or a reduction in the VOC content of the wastewater as a 
result of process modifications, modifications of operating practices, 
improved preventive maintenance activities, increased recycling, or 
segregation of VOC-containing waste streams.
    Waste minimization may be achieved through either source reduction 
or recycling. Source reduction involves the implementation of steps 
that reduce either the amount of wastewater generated or the amount of 
VOC contained in the wastewater streams. Recycling includes recovery 
and/or reuse of potential wastes. Within the SOCMI, there are several 
means of achieving the objective of either of these waste minimization 
alternatives. However, in relation to SOCMI wastewater, waste 
minimization techniques are, for the most part, process unit-specific, 
and the degree of emission reduction achieved depends on the operating 
parameters of the individual process unit.
    Because of a lack of adequate site-specific data regarding the 
waste minimization approach within SOCMI, the EPA was unable to develop 
reasonable estimates of the emission control efficiency of the waste 
minimization options achievable on a nationwide basis. For example, 
because pollution prevention activities such as process redesign are 
site-specific, it would not be practical or possible to stipulate 
specific requirements for the large number of chemical production 
processes subject to the proposed SOCMI wastewater NSPS. In addition, 
the EPA considers that elimination of pollution through material 
substitution will not be possible in all cases within the SOCMI because 
SOCMI products cannot be eliminated from use without adverse economic 
impact. Specifically, because the products of the SOCMI are used in the 
production of polymers, resins, pesticides, pharmaceuticals, etc., 
elimination of a SOCMI product would affect not only the SOCMI producer 
but also the downstream user of that SOCMI product. Many of the end-use 
products (e.g., resins, pharmaceuticals, etc.) could not be made from 
other materials. Thus, the EPA maintains that material substitution is 
better left determined by the marketplace than by mandate through a 
specific Federal requirement. Therefore, for the reasons cited above, 
no waste minimization options were included in the regulatory 
alternatives analysis for this NSPS.
    The EPA, however, believes that the SOCMI wastewater NSPS 
sufficiently encourages pollution prevention. For example, within the 
regulation's applicability provisions, there is an exemption from the 
control requirements of the rule for process units that generate 
wastewaters with small overall volatile organic quantities in the 
wastewater. Also, the regulatory criteria for identifying the 
wastewater streams that require control for air emissions are expressed 
in terms of action levels based on concentration and flow rate cutoffs 
below which controls are not required for the wastewater stream. An 
owner or operator may use any means, including process changes or 
material substitution but not treatment of the wastewater, to meet the 
criteria for either the small quantity process unit exemption or the 
concentration/low-flow cutoff. In addition, within the provisions for 
wastewater collection and treatment operations, there are compliance 
options that only specify a percent reduction of VOC emissions. Again, 
to comply with these options, an owner or operator may use any means, 
including process changes or recovery devices, to reduce emissions by 
the specified percent.
    The second approach to achieving emission reductions involves 
emission suppression and treatment of wastewater streams to remove or 
destroy the organic compounds. Volatile organic compound emissions from 
SOCMI process unit wastewater can be effectively reduced on a 
nationwide basis with the following control approach: (1) Identify 
wastewater streams with significant VOC emission potential; (2) recycle 
or treat those wastewater streams to remove their potential for 
emissions; (3) prior to treatment or recycling, manage those waste 
streams in units that suppress emissions or are equipped with air 
emission controls; (4) recycle any treatment residuals or treat any 
residuals to destroy VOC; and (5) control air emissions generated by 
the treatment processes.
    The potential for VOC emissions from wastewater can be assessed 
based on the characteristics of the wastewater at its point of 
generation. A reference test method, EPA Method 25D (40 CFR Part 60, 
appendix A), provides a relative indicator of wastewater emission 
potential and is used as a tool to implement air emission standards for 
wastewater. This method, when applied to a wastewater stream, yields a 
volatile organic concentration for the stream. While not a true 
indicator of absolute emissions, the volatile organic content of a 
stream provides a relative indicator of the potential emissions of that 
stream as compared to other streams that are similarly managed.
    There are three primary treatment technologies that are generally 
applicable and effective in reducing the VOC content of SOCMI 
wastewater streams. These are steam stripping, air stripping, and 
biological treatment. There also are several other technologies or 
methods of treatment that are equally effective in their particular 
situations but are limited in their applicability within SOCMI. These 
other technologies include chemical oxidation, carbon and ion exchange 
adsorption, membrane separation, and liquid-liquid extraction.
    Steam stripping is the most universally applicable VOC removal 
technology for treating wastewater streams generated by SOCMI process 
units, and this treatment technology has been selected as the basis for 
standards for SOCMI wastewater. The VOC removal efficiency of steam 
strippers depends on the characteristics of both the steam stripper and 
the wastewater stream. Data collected by the EPA related to steam 
stripper performance for the treatment of wastewaters indicate that 
organic removal efficiencies of up to 99.9 percent have been 
demonstrated on wastewater streams at SOCMI plants.
    The EPA selected steam stripping as the BDT because it is the most 
universally applicable treatment technology for removing organic 
compounds from wastewater streams with the potential to emit VOC and 
achieves the highest VOC emission reduction among demonstrated VOC 
control technologies. The EPA is aware that many SOCMI facilities 
employ biological treatment units for wastewater treatment. However, 
not all of the compounds regulated under the proposed NSPS are 
significantly biodegradable, while most of the compounds can be treated 
more readily by steam stripping. In addition, the amount of emissions 
reduction achieved by biological treatment, even for biologically 
degradable compounds, will vary among SOCMI sources because of the 
ranges in operating and design parameters, such as the biological 
degradation rate, surface area of the unit, aeration rate, hydraulic 
residence time, and the active biomass concentration. When reviewing 
biological treatment as the potential BDT, the EPA determined that the 
variability in performance is significant across the industry. Although 
a well operated and maintained biological treatment system can achieve 
reductions as high as 99 percent, the variability in performance makes 
quantifying emission reductions for the purpose of setting a standard 
more difficult than for steam stripping. Emission reductions for 
biological treatment systems can only be determined on a site-specific 
basis. However, the EPA emphasizes that SOCMI sources using biological 
treatment, or any other treatment technologies, can comply with the 
rule by consistently achieving the required emission reduction (i.e., 
95 percent when using biodegradation or 99 percent for other 
technologies).
    To achieve the desired emission reduction from steam stripping or 
other treatment technology, it is necessary to suppress the wastewater 
emissions from the point of generation to the treatment device where 
the organic compounds are either removed or destroyed. Suppression of 
emissions can be achieved by using physical covers, roofs, and water 
seals to minimize the contact between the wastewater and the 
atmosphere. Examples of controls for air emissions from waste 
management units in a wastewater collection and treatment system, based 
on suppression techniques, include: fixed or floating roofs on tanks, 
water seals on drains, gas-tight covers on junction boxes, and covers 
and enclosures around oil-water separators. Hard piping of a wastewater 
stream from its point of generation to the steam stripper unit is one 
method to achieve the suppression of air emission from the wastewater. 
However, wastewater streams may be managed in other units prior to 
treatment if those units are equipped with air emission controls.

F. Selection of Format of Proposed Standard

    Section 111 of the Act requires an emission standard whenever it is 
feasible. Section 111(h) states that ``if in the judgment of the 
Administrator, it is not feasible to prescribe or enforce a standard of 
performance, he may instead promulgate a design, equipment, work 
practice, or operational standard, or combination thereof * * * '' The 
term ``not feasible'' is applicable if the emissions cannot be captured 
and vented through a vent or stack designed for that purpose, or if the 
application of a measurement methodology is not practicable because of 
technological or economic limitations. The EPA is proposing standards 
for VOC emissions from the process unit wastewater segment of this 
source category. To ensure that emissions are captured and conveyed to 
a control device, the proposed standards include requirements for:
    (1) An enclosed wastewater collection and treatment system;
    (2) Treatment to reduce VOC concentration in the wastewater 
streams; and
    (3) Conveyance of emissions vented from the wastewater treatment 
device and the enclosed wastewater collection system in a closed-vent 
system to a control device.

Applicability levels are included in the SOCMI wastewater standards to 
identify those process unit wastewater streams that are required to be 
controlled. Alternative formats were considered for applicability 
levels, waste management units, wastewater treatment processes, and 
vent collection and vapor recovery or destruction devices.
1. Applicability Levels
    The EPA identified certain low flow and low concentration 
wastewater streams that are not believed to be controlled at existing 
facilities. Parameters that characterize these streams include volatile 
organic concentration of the stream and volumetric flow rate, both of 
which can be determined by using a variety of methods. Therefore, the 
EPA is proposing concentration and flow rate parameters to identify 
process unit wastewater streams that do not require control. The EPA 
also is proposing that process units that generate wastewater with a 
total annual mass of volatile organics less than 1 Mg per year are 
exempt from the control requirements of the rule. The EPA solicits 
comment on whether it is feasible to otherwise identify specific 
process unit wastewater streams to be controlled. The EPA also solicits 
information on defining these process unit wastewater streams.
2. Waste Management Units
    Two formats were considered in developing the proposed standards 
for waste management units. These formats were a numerical emission 
standard and an equipment and work practice standard. A numerical 
standard would not be feasible because it would be difficult to capture 
and measure emissions from SOCMI waste management units (i.e., tanks, 
surface impoundments, containers, individual drain systems, and oil-
water separators) for the purpose of evaluating compliance. Due to the 
number of openings and possible emissions points, accurate measurement 
would require enclosure of the entire airspace around each piece of 
equipment. This approach would not be practical for numerous equipment 
components. Therefore, the Administrator concluded that the format of 
the standards for this source category should include a combination of 
a design, equipment, work practice, and operational standards.
    In the case of SOCMI waste management units, the intent of the 
standard is to suppress and capture emissions from the process unit 
wastewater collection and treatment equipment. The suppression and 
capture of emissions is accomplished by the installation and proper 
maintenance of roofs, covers, lids, water seals, and enclosures on 
tanks, surface impoundments, containers, individual drain systems, and 
oil-water separators. Captured emissions are then vented to a control 
device through application of a closed vent system. Work practices such 
as periodic monitoring, inspection, and repair, would be required to 
ensure proper operation and maintenance of the equipment.
    The proposed standards would require that emissions from waste 
management units be controlled from the point of generation until the 
wastewater stream leaves the treatment device or is recycled to the 
process.
3. Wastewater Treatment Processes
    Three formats were considered in developing the proposed standards 
for reduction of process unit wastewater stream VOC concentration: a 
numerical format (i.e., emission standard), an equipment design and 
operational format, and an equipment and work practice standard.
    a. Emission Limitation. Three alternative numerical emission 
limitation formats are proposed to provide sources with a maximum 
degree of operational flexibility in complying with the standards. 
These emission limitation formats are: a mass percent reduction of VOC 
in the process unit wastewater stream, an effluent concentration 
limitation for VOC for individual wastewater streams, or a mass removal 
requirement for combined wastewater streams. The rationale for 
providing these alternative emission limitations is discussed below.
    The percent reduction format is based on the VOC removal efficiency 
of a steam stripper; however, any treatment process that can achieve 
the proposed efficiency can be used to comply with the standard. (See 
section IV.G for more discussion.) Percent reduction was chosen because 
it is the best representation of control technology performance, and it 
may be applied to any configuration of wastewater streams.
    The effluent concentration limitations are also based on the 
performance of a steam stripper. Effluent concentration limitations are 
provided as alternatives to the percent reduction standard to allow 
compliance flexibility for facilities required to treat process unit 
wastewater streams. The use of this alternative is limited to 
facilities that are treating only affected wastewater streams. The 
effluent concentration limit is not applicable to situations where 
combinations or mixtures of both affected and unaffected wastewater 
streams are treated.
    Dilution becomes a concern when more than one waste stream is sent 
to a single treatment process. For example, diluting a waste with other 
materials having a volatile organic concentration less than 500 ppmw as 
a means by which an owner or operator lowers the volatile organic 
concentration of the waste from an affected stream to a level below 500 
ppmw would not comply with the requirements of the proposed standards. 
A process that simply mixes, blends, combines, or aggregates a waste 
with other materials does not destroy the VOC in the waste or remove 
the VOC from the waste. Consequently, when a waste is treated by an 
organic destruction or removal process, and the waste has been mixed or 
aggregated together with other wastes or materials with a volatile 
organic concentration less than 500 ppmw prior to the point of waste 
treatment, the proposed standards would require that owners or 
operators meet special requirements to ensure that organics in the 
waste have actually been removed or destroyed. Under the proposed 
rules, an owner or operator would be allowed to use a mass reduction 
requirement to meet the standards.
    Required mass removal is an alternative for combined wastewater 
streams. This provision would require that mixed wastes be treated by 
an organic destruction or removal process that reduces the volatile 
organic concentration of the waste to meet a site-specific treatment 
process mass removal limit. This limit would be determined by the owner 
or operator on a case-by-case basis using an equation specified in the 
rules that accounts for the reduction in the volatile organic 
concentration of the resulting treated waste stream due to dilution. To 
use this equation, the owner or operator would first determine the 
volatile organic concentration at the point of waste entry for each 
individual waste stream that is mixed together prior to entering the 
treatment process.
    b. Equipment Design and Operation Format. Another regulatory format 
proposed for process unit wastewater stream treatment is an equipment 
design and operational format. The equipment standard consists of the 
installation of a steam stripper designed and operated at specified 
parametric levels. The specifications for the steam stripper were 
developed to provide a standard piece of equipment (with associated 
operating conditions) that can achieve either the mass percent VOC 
removal or the effluent concentration of VOC.
    This equipment design and operational format was included to 
provide an alternative means of compliance that all sources would be 
able to use, while achieving the desired emission reduction.
    c. Equipment and Work Practice Format. A final equivalent standard 
proposed for controlling process unit wastewater emissions is an 
equipment and work practice standard. This format is based on the 
recycling of process unit wastewater in a closed collection system to 
the process. When recycling is used, process unit wastewater emissions 
are controlled with equipment emissions, and the process unit 
wastewater is reused. This format is proposed to encourage chemical 
recovery and waste minimization and pollution prevention.
4. Vent Collection and Vapor Recovery or Destruction Devices
    An emission standard and two equipment and design standards are 
proposed for VOC that are routed to vapor recovery or destruction 
devices used to control VOC from vent collection sources. The proposed 
emission standard includes two alternatives: a weight percent reduction 
and an outlet concentration. A mass emission limit was not appropriate 
for these emission points because variation within the industry, 
including capacity and processes, greatly affects emission rates, and 
data were not available to determine the mass limits that would address 
this variation. In general, a weight percent reduction format will 
ensure that BDT is applied and the required emission reductions are 
realized. However, combustion technology that is equivalent to BDT 
cannot be demonstrated to achieve the selected percent reduction for 
streams with low VOC concentrations. Therefore, an alternative 
concentration limit that is achievable has been included. The 
combination of the weight percent reduction or concentration limit will 
ensure that the best technology is applied to all SOCMI process 
emission points, whether they have higher or lower concentrations.
    Two equivalent standards, each of which is an equipment and design 
standard, are also proposed. The first equipment and design standard is 
the requirement that gas streams be routed to a combustion device 
(other than flares) designed and operated at a minimum temperature and 
residence time. For flares, an equipment standard with stated equipment 
and operating specifications is being proposed as the format because it 
is very difficult to measure emissions from a flare to determine its 
efficiency. These standards have been determined by the EPA to be 
equivalent to the emission standards and are proposed to provide 
maximum compliance flexibility.

G. Selection of Standards

    This section discusses the rationale for the selection of the 
standards for the SOCMI process unit wastewater source category. The 
selection of applicability levels, numerical limitations for the 
emission standards, and design parameters are included.
1. Applicability Levels
    For the purposes of developing wastewater standards, the EPA has 
concluded that the effectiveness of the control technologies available 
to limit VOC emissions from wastewater does not vary. Controls are 
assumed to be either ``on'' or ``off,'' depending on whether a 
particular stream is identified as one that must be controlled. 
Therefore, the basic foundation of the proposed provisions for SOCMI 
process unit wastewater is to identify wastewater streams for control 
and treatment based on a specific criteria or action level at the point 
of wastewater generation, prior to dilution and air emissions losses. 
Control of a wastewater stream is triggered if it is determined that 
the stream exceeds the action level established by the standard. With 
this approach, the primary decision that needs to be made in 
establishing BDT is selecting the appropriate action level for the 
source category.
    Regulatory alternatives for a standard to control emissions from 
wastewater have, in previous EPA regulatory analyses, been typically 
expressed in terms of action levels based on a concentration cutoff 
above which a wastewater stream must be controlled. For the SOCMI 
wastewater NSPS, the primary action level will be defined in terms of 
the volatile organic concentration, as measured by method 25D. The 
standard also includes exemptions for low flow streams. This is in 
consideration of the fact that, even though a waste stream may exceed 
an action level, the total mass of contaminant present in a stream with 
a low flow rate is low enough that the waste or wastewater stream does 
not have the potential for significant emissions. Process units that 
generate wastewater with a total annual volatile organic mass less than 
1 Mg are also exempt from the control requirements of the proposed 
rule. The impacts analysis indicated that the 1 Mg/yr small quantity 
exemption has little effect on the emission reductions achieved under 
the regulatory alternatives examined while significantly reducing the 
overall cost of compliance.
    The five regulatory alternatives analyzed in the development of the 
proposed standard were combinations of volatile organic concentrations 
and flow rate cutoffs. The alternatives were analyzed both with and 
without the small quantity cutoff of 1 Mg per year of volatile organic 
mass. For each regulatory alternative, steam stripping (or an 
equivalent emission reduction technique) would be required for all 
wastewater streams with flow rates and volatile organic concentrations 
greater than their respective action levels.
    Values were chosen for concentration and flow rate cutoffs to span 
ranges believed by the EPA to be reasonable based on knowledge of the 
SOCMI wastewater streams to be regulated and on previous standards 
development efforts. Further, the ranges of flow rates and 
concentrations represented in these alternatives, when impacts are 
estimated, illustrate the range of cost-effectiveness levels that apply 
to regulatory alternatives and allow selection of an alternative that 
will achieve optimum control (i.e., greatest emission reduction for 
lowest cost).
    As previously noted, method 25D provides a relative indicator of 
wastewater emission potential. While not a true measure of VOC 
emissions, the volatile organic concentration of a wastewater stream 
does provide a relative means of comparing the emission potential of a 
wastewater stream to other streams similarly managed and of comparing 
the emission potential of a wastewater stream before and after 
treatment.
    Because the proposed rule regulates VOC emissions, the first choice 
for a test method is one that measures the concentration of all VOC. 
However, this approach would require speciation test methods which are 
costly to use. As an alternative, the EPA selected method 25D which 
does not speciate but measures total volatile organic concentration. 
This method, which is much less costly, has been used in other 
wastewater related regulations. For example, method 25D is allowed in 
the HON for measuring volatile organic concentration in applicability 
determinations. However, the HON does not allow use of method 25D in 
calculations of mass removal for treatment processes. Instead, the HON 
uses a test method that speciates HAPs for determining mass removal by 
treatment.
    As currently structured, the proposed rule would make extensive use 
of the volatile organic concentration (as measured by Method 25D). The 
concentration cutoffs for determining if a wastewater stream is an 
affected stream are formatted in terms of the volatile organic 
concentration. The small quantity cutoff of 1 Mg/yr is calculated using 
the volatile organic concentration; the effluent concentration limit is 
expressed in term of volatile organic concentration; and the mass 
removal requirements of the proposed rule are calculated using the 
volatile organic concentration. The EPA is aware that using the 
volatile organic concentration rather than a direct measure of VOC does 
have some limitations and drawbacks. The test method used to measure 
volatile organic concentration, Method 25D, is based on volatility 
(i.e., Henry's Law) and does not speciate organic compounds. Therefore, 
the results may reflect the presence of compounds that are not 
considered VOC (based on their photochemical reactivity). The EPA is 
considering ways of discounting the non-VOC components of the test 
results but has not included a means to do so in the proposed 
regulation. One option for accomplishing this would be to allow owners 
or operators the option of using a test method that speciates VOC. If 
this approach is selected, provisions could also be made to allow the 
measured VOC concentration to be adjusted to represent VO concentration 
by multiplying by the fraction emitted (fm) values reported in the 
IWW CTG. The EPA also intends to include an alternative percent 
reduction standard based on the stripability of specific volatile 
organic constituents. This approach is also described in the IWW CTG. 
Because of the issues associated with the use of method 25D for 
applicability and compliance determinations, the EPA is soliciting 
comments all aspects of this approach.
    Regulatory Alternative 1 is to require emission control only of 
those SOCMI process unit wastewater streams having a volatile organic 
concentration at the point of wastewater generation equal to or greater 
than 1,000 ppmw and a flow rate greater than or equal to 10 Lpm. 
Regulatory Alternative 2 is to require emission control only of those 
SOCMI process unit wastewater streams having a volatile organic 
concentration at the point of wastewater generation equal to or greater 
than 800 ppmw and a flow rate greater than or equal to 5 Lpm. 
Regulatory Alternative 3 is to require emission control only of those 
SOCMI process unit wastewater streams having a volatile organic 
concentration at the point of wastewater generation equal to or greater 
than 500 ppmw and a flow rate greater than or equal to 1 Lpm. 
Regulatory Alternative 4 is to require emission control only of those 
SOCMI process unit wastewater streams having a volatile organic 
concentration at the point of wastewater generation equal to or greater 
than 100 ppmw and a flow rate greater than or equal to 1 Lpm. 
Regulatory Alternatives 1 through 4 also have a maximum volatile 
organic concentration limit whereby any wastewater stream with a 
volatile organic concentration above the limit would require emission 
control regardless of the wastewater stream flow rate; for Regulatory 
Alternatives 1 through 4, the same maximum concentration limit of 
10,000 ppmw was used in the regulatory alternatives analysis. 
Regulatory Alternative 5 is to require air emission control for all 
SOCMI process unit wastewater streams with any detectable volatile 
organic concentration as determined at the point of wastewater 
generation (i.e., a volatile organic concentration action level of 0 
ppmw).
    The EPA estimated nationwide VOC emission reductions that would be 
achieved by implementing air rules based on each of the five regulatory 
alternatives; the EPA also estimated the capital and annual cost of 
achieving the emission reductions and the nonair quality environmental 
and energy impacts associated with each regulatory alternative. These 
estimates of emissions and costs reflect the annual impacts in the 
fifth year following promulgation of the NSPS. The methodology used to 
develop estimates of VOC emissions and other impacts within the SOCMI 
source category for the five regulatory alternatives is based on the 
use of a model plant analysis and is discussed in detail in Chapter 6 
of the BID and in docket number A-94-32.
    Model plants are typically defined to represent the affected 
facility over a range of sizes corresponding to the range found in the 
regulated industry. Two previous EPA studies developed model plants 
that relate to emissions from wastewater streams at SOCMI facilities: 
the Guideline Series Document for the Control of Volatile Organic 
Compound Emissions from Industrial Wastewater (EPA-453/D-93-056, 
September 1992 Draft) and the BID related to the development of the HON 
(EPA-453/D-92-016, November 1992). The EPA developed model plants for 
the SOCMI wastewater NSPS regulatory analysis by making use of 
information, data, and methodologies developed in these previous 
studies.
    In the absence of implementing any of the regulatory alternatives 
(baseline), nationwide, fifth-year wastewater VOC emissions from new, 
modified, and reconstructed SOCMI process units are estimated to be 
approximately 37.2 thousand Mg/yr. Assuming implementation of the 
individual regulatory alternatives, the emissions are 24.1 thousand Mg/
yr for Regulatory Alternative 1, an emission reduction from baseline of 
13.0 thousand Mg/yr achieved at total annual cost of about $4.3 
million; 23.1 thousand Mg/yr for Regulatory Alternative 2, an emission 
reduction from baseline of 14.0 thousand Mg/yr achieved at total annual 
cost of about $5.2 million; 21.0 thousand Mg/yr for Regulatory 
Alternative 3, an emission reduction from baseline of 16.2 thousand Mg/
yr achieved at total annual cost of about $8.8 million; 18.6 thousand 
Mg/yr for Regulatory Alternative 4, an emission reduction from baseline 
of 18.6 thousand Mg/yr achieved at total annual cost of about $15.6 
million; and 14.2 thousand Mg/yr for Regulatory Alternative 5, an 
emission reduction from baseline of 22.9 thousand Mg/yr achieved at 
total annual cost of about $41.1 million.
    The control costs reflect the fact that most plants affected by the 
NSPS will also be affected by the HON, and they are expected to install 
a steam stripper for treating wastewater streams regulated by the HON. 
The proposed NSPS will require these SOCMI plants to control additional 
wastewater streams that do not require control under the HON. In 
estimating cost impacts of the NSPS, the EPA assumed that those plants 
affected by both regulations would increase the capacity of the steam 
stripper required under the HON rule to provide sufficient capacity to 
handle the additional wastewater streams that would require control 
under the NSPS. The costs associated with the NSPS is the difference in 
costs for the two steam strippers, one with the capacity to handle 
wastewater streams regulated by the HON and the other with the capacity 
to handle wastewater streams regulated by both the HON and the NSPS.
    After considering the alternatives and the emission reductions 
achieved, the resulting control costs, and other associated impacts, 
the EPA concluded that the control requirements in Regulatory 
Alternative 3 reflect the application of the best system of emission 
reduction that has been adequately demonstrated.
    A more stringent level of emissions limitation was not selected 
because control beyond Regulatory Alternative 3 would result in costs 
that are disproportionately large compared to the additional emission 
reduction achieved. Regulatory Alternatives 4 and 5 were estimated to 
achieve an additional emission reduction of about 2.4 thousand and 6.7 
thousand Mg/yr, respectively, at an additional cost of about $6.8 
million or $32.3 million for the two alternatives.
    Under the proposed rule, the control requirements for new, 
modified, and reconstructed SOCMI process units would apply to two sets 
of wastewater streams: streams with flow rates of 1 Lpm or greater and 
a volatile organic concentration of 500 ppmw or greater; and any stream 
with a volatile organic concentration of 10,000 ppmw or greater 
(regardless of flow rate).
2. Process Wastewater Collection System
    As discussed previously, effective control of SOCMI process unit 
wastewater emissions requires control from the point of generation 
until treated to comply with the treatment standards, or until recycled 
to a controlled process unit that is in compliance with the standards. 
The proposed standards require that emissions be controlled during 
wastewater collection and transport in piping or individual drain 
systems and during handling and treatment in wastewater tanks, 
containers, surface impoundments, and treatment devices by using 
covers, lids, water seals, roofs, and enclosures designed to reduce 
emissions. Proper work practices, including periodic monitoring, 
inspection, and repair, are also required to ensure that the equipment 
will control emissions. Emissions from these wastewater collection, 
transport, and handling systems are believed to be significant, thereby 
requiring the use of controls to effectively reduce air emissions.
3. Process Wastewater Treatment
    The proposed regulation provides four options for demonstrating 
compliance with the SOCMI process unit wastewater treatment standards: 
three treatment options based on numerical emission limitations and an 
equipment and design specification. Of the options based on numerical 
emission limitations, the first option may be adopted by all affected 
sources. The remaining options based on numerical emission limitations 
may only be used by certain classes of sources, as discussed below. Any 
facility may choose to use the equipment and design specification as an 
alternative to the emission limitation requirements.
    The first treatment process compliance option is removal of VOC 
from the wastewater based on the removal efficiency of the BDT, which 
is a design steam stripper (i.e., a steam stripper meeting specific 
design and operational criteria). Under this equipment and design 
standard option for demonstrating compliance with the process 
wastewater treatment standard, if the owner or operator installs and 
operates a steam stripper that meets the requirements, listed below, 
the treatment unit is in compliance with the treatment process standard 
of the rule. These design and operating parameters include:
    (1) Minimum active column height of 5 meters;
    (2) Countercurrent flow configuration with a minimum of 10 actual 
trays;
    (3) Minimum steam flow rate of 0.04 kilograms of steam per liter of 
wastewater feed;
    (4) Minimum wastewater feed temperature to the steam stripper of 95 
degrees Centigrade;
    (5) Maximum liquid loading of 67,100 liters per hour per square 
meter; and
    (6) Minimum steam quality of 2,765 kilojoules per kilogram.
    The first of three additional treatment process compliance options 
that are formatted as a numerical emission limitations is a requirement 
for 99-percent removal of volatile organic mass from the wastewater. 
The 99-percent removal may be achieved through use of steam stripping 
on other control technologies. For example, another way to achieve the 
99-percent removal is through air stripping.
    A second treatment process compliance option that is provided for 
demonstrating compliance is to treat the wastewater stream to achieve a 
volatile organic concentration of 50 ppmw provided the owner or 
operator demonstrate a volatile organic mass removal of 95 percent or 
greater. This treatment option is provided to allow additional 
flexibility for the owner in demonstrating compliance with the 
wastewater treatment standard; treatment of wastewater streams to a 
concentration of less than 50 ppmw generates a wastewater stream that 
would require no additional control from the point at which it exits 
the treatment unit. This option is limited in its applicability for the 
reasons discussed in Section IV.F.3. The 50 ppmw limit was selected 
based on analysis characterizing the volatile organic concentration of 
wastewater streams in the SOCMI database that would be subject to the 
proposed standards both before and after treatment. The limit is the 
minimum concentration that characterizes the volatile organic level of 
SOCMI wastewater streams treated to comply with the proposed standards 
using the BDT steam stripper.
    The third numerical emission limitation option for demonstrating 
compliance is to remove a calculated mass of VOC from a wastewater 
stream where the mass of VOC to be removed is calculated on the basis 
of the annual average wastewater density and flow rate and the volatile 
organic average concentration in the wastewater stream. This option is 
designed to accommodate the control of combined streams for the reasons 
discussed in section IV.F.3.
    The proposed rule also provides an alternative treatment process 
compliance option for biological treatment units; under the 
alternative, an owner or operator must treat affected wastewater 
streams in a biological treatment unit that destroys at least 95 
percent of the organics. The EPA is allowing a 95-percent destruction 
efficiency for biological treatment units as a compliance alternative 
for the treatment process standards in part because the Agency believes 
the use of these units will have the effect of increasing the overall 
mass reduction achieved under the rule. This results from the fact that 
if affected wastewater streams are allowed to be managed in a 
biological treatment unit, then it is fully expected that other non- 
affected wastewater streams would also be managed in these biological 
treatment units, resulting in additional control achieved or streams 
that may not otherwise be controlled under the regulation. The 
alternative for biotreatment units in this rule is also consistent with 
other regulations regarding wastewater treatment, such as the 
biotreatment provisions of the HON.
4. Vent Collection for Vapor Recovery or Destruction
    Volatile organic compounds are emitted from vents on enclosed or 
covered process wastewater collection and treatment system devices such 
as individual drain systems and steam strippers. These emissions are 
required to be vented through a closed-vent system meeting the 
requirements established in the rule. The closed-vent system must route 
these vapors to a vapor recovery or destruction device achieving at 
least a 95-percent destruction or recovery. This limitation is based on 
the average efficiency of a conventional VOC recovery devices. The 
option of meeting an equivalent standard (achieving an outlet 
concentration of 20 ppm by volume on a dry basis corrected to 3 percent 
oxygen or providing a minimum residence time and temperature) for 
enclosed combustion devices is provided as well.
    Because biological treatment units destroy the VOC in the 
wastewater, a well-operated biological treatment unit is not required 
to be covered and vented to vapor recovery and destruction. Instead, 
the proposed regulation requires an owner or operator electing to use a 
biological treatment unit to meet the 95 percent control requirement by 
demonstrating that 95 percent of the volatile organic entering the 
biological treatment unit is being destroyed and not emitted to the 
atmosphere.

H. Modification and Reconstruction Considerations

    Under the General Provisions for modification (40 CFR 60.14) and 
reconstruction (40 CFR 60.15), facilities that are modified or 
reconstructed after the date of proposal of a standard are subject to 
the standard. An owner or operator of an existing facility who is 
planning changes in the facility that could be considered modification 
or reconstruction shall notify the appropriate EPA Regional Office 60 
days prior to making the changes or commencing construction, as 
applicable. The enforcement division of the appropriate EPA Regional 
Office will make the final determination as to whether an existing 
facility is modified or reconstructed and, as a result, subject to the 
standards of performance of an affected facility.
1. Modification
    Upon modification of any emission source, an existing facility 
becomes an affected facility and therefore, subject to the standard. 
With certain exceptions, any physical or operational change to an 
existing process unit that would increase the emission rate from that 
process unit of any pollutant covered by the standard would be 
considered a modification within the meaning of section 111 of the Act. 
If a physical or operational change to an existing process unit would 
increase VOC emissions from the process unit, the owner or operator 
either can take appropriate measures to offset the emission increase 
within the process unit such that there is no overall net increase in 
emissions from the process unit as a result of the physical or 
operational change, or allow the process unit to be classified as an 
affected facility under the modification criteria and control the 
process unit to meet the requirements of the NSPS.
    Under the current regulations, an emission increase from one 
affected facility (i.e., process unit) may not be offset with a similar 
emission decrease at another affected facility to avoid becoming 
subject to NSPS. In addition, all emissions, not just the incremental 
increase in emissions, of the pollutants that have increased from the 
affected facility must be in compliance with the applicable standards.
    Under the General Provisions to part 60, the following physical or 
operational changes are not considered to be modifications even though 
emissions may increase as a result of the change (see Sec. 60.14(e)):
    1. Routine maintenance, repair, and replacement (e.g., lubrication 
of mechanical equipment; replacement of pumps, motors, and piping; 
cleaning of equipment);
    2. An increase in production rate without a capital expenditure (as 
defined in Sec. 60.2);
    3. An increase in the hours of operation;
    4. Use of an alternative fuel or raw material if, prior to proposal 
of the standard, the existing facility was designed to accommodate that 
alternative fuel or raw material;
    5. The addition or use of any system or device whose primary 
function is to reduce air pollutants, except when an emission control 
system is replaced by a system determined by the EPA to be less 
environmentally beneficial; and
    6. Relocation or change in ownership of the existing facility.
    The following discussion identifies some possible changes to 
process unit operations used in SOCMI that might be considered 
modifications. The magnitude of the industry covered and the complexity 
of the manufacturing process permit only a general discussion of these 
possible changes. Therefore, the list of potential modifications for 
process units provided below is not inclusive.
    a. Feedstock, Catalyst, or Reactant Substitution. Feedstock, 
catalyst, or reactant substitution is dictated by economics and the 
level of availability of the feedstock, catalyst, or reactant. 
Depending upon the specific process, changes in feedstock or catalyst 
may require substantial capital investment to modify the process to 
accommodate the change. The magnitude of the capital investment may 
prohibit feedstock or catalyst substitution for many chemicals.
    Many of the chemicals produced in the SOCMI can be manufactured 
from two or more different feedstocks. For example, cyclohexane can be 
manufactured using either phenol or cyclohexanol as the feedstock. In 
most cases, however, feedstock substitution would likely require both 
equipment and process changes.
    Substitution of reactants within the SOCMI process units is also a 
likely change that could constitute a modification. For example, for 
many chemicals, the potential exists to substitute air for pure oxygen 
or a chemical oxidant as a reactant or vice versa. Changing to an air 
oxidation process may be advantageous because: (1) Air is readily 
available; and (2) expensive corrosion-resistant materials are not 
required compared to the use of chemical oxidants. However, there may 
be major disadvantages in changing from an oxygen or chemical oxidation 
process to an air oxidation process, including a substantial reduction 
in plant capacity, a large increase in the reactor-related process vent 
stream flow rate (i.e., increased VOC emissions), and an altered 
product mix. The use of oxygen or air oxidation may be substituted for 
chemical oxidation processes as well. Reactant substitutions of this 
type may increase process unit VOC emissions to the atmosphere and, as 
a result, may constitute a modification (unless the fixed capital 
expenditure exceeds 50 percent of the fixed capital cost required to 
construct a comparable new facility, in which case it would be 
considered reconstruction).
    b. Process Equipment Changes. Process equipment changes also may 
constitute modifications. Examples of potential modifications are 
replacing a fixed-bed reactor with a fluidized-bed reactor, increasing 
the plant capacity by increasing the size of the reactor or adding 
additional reactors, and changing the product recovery system (e.g., 
from an absorber to a condenser). Such changes might be considered 
modifications because they can result in increased VOC emissions. 
Again, capital expenditures may be a factor in determining whether the 
change is a modification or a reconstruction.
    c. Combinations. A combination of the changes described above could 
be chosen in any given situation with the decision based on the most 
advantageous economics for the site-specific conditions. The 
combination of changes might be considered a modification if they 
resulted in an increase in emissions. The most common combinations are 
plant expansions or simultaneous changes in feedstock and catalyst as 
described earlier.
2. Reconstruction
    An existing facility may become subject to NSPS if it is 
reconstructed. Reconstruction is defined in Sec. 60.15 as the 
replacement of the components of an existing facility to the extent 
that: (1) The fixed capital cost of the new components exceeds 50 
percent of the fixed capital cost required to construct a comparable 
new facility; and (2) it is technically and economically feasible for 
the facility to meet the applicable standards. Because the EPA 
considers reconstructed facilities to constitute new construction 
rather than modification, reconstruction determinations are made 
irrespective of changes in emission rates. If the facility is 
determined to be reconstructed, it must comply with all of the 
provisions of the standards of performance applicable to that facility.

I. Monitoring Requirements

    The proposed standards include requirements for continuous 
monitoring to ensure that owners suppress and capture emissions from 
the process unit wastewater collection system, treat the wastewater to 
reduce the VOC concentration, and convey emission from the wastewater 
collection and treatment to a control device as specified in the 
regulation. The specific parameters that need to be monitored are 
discussed below.
    Enhanced monitoring is required for certain control device 
parameters to demonstrate compliance with the standards. Failure to 
maintain the established values of the monitored parameters would be an 
enforceable violation of the emission limits of the standard.
1. Wastewater Collection
    The standards require monitoring to ensure that the wastewater 
collection system equipment, which includes tanks, surface 
impoundments, containers, and drain systems, is operated with no 
detectable leaks. The standards require owners or operators to monitor 
initially using Method 21 to demonstrate that the system has no 
detectable leaks according to the procedures in the rule. The standards 
also include a requirement for semi-annual visual inspection of the 
wastewater collection system to detect and repair any leaks in the 
individual drain system.
2. Wastewater Treatment
    The proposed regulation requires each owner or operator using a 
steam stripper to comply with the design and equipment standard 
specified for wastewater treatment processes to install, calibrate, 
operate, and maintain according to manufacturers' specifications 
continuous monitors with continuous recorders of:
    (1) The mass rate of wastewater fed to the stripper;
    (2) The mass rate of steam fed to the stripper; and
    (3) The wastewater column feed temperature.
    These parameters are either established during an initial 
performance test or according to design specification in the 
regulation. They are typically monitored in the industry to ensure 
proper operation; therefore, ensuring continuous compliance of a steam 
stripper with the specified requirements for VOC removal requires no 
additional monitoring burden.
    Owners or operators using a biological treatment unit to achieve a 
95-percent total VOC reduction across the unit are required to measure 
the volatile organic concentration in the influent and effluent on a 
monthly basis and identify appropriate parameters to be monitored to 
ensure continuous compliance. These parameters must be determined 
during the initial performance test as demonstrated to the 
Administrator's satisfaction, and monitored accordingly.
3. Enclosure and Closed-vent System Monitoring Requirements
    The proposed rule establishes requirements to ensure that negative 
pressure is maintained on enclosures and that emissions are routed 
through a closed-vent system with no detectable leaks. If the closed-
vent system contains bypass lines, the proposed standards require the 
owner or operator to ensure emissions are not bypassing the control 
device.
    An initial performance test must be conducted to ensure that 
negative pressure is maintained on all openings of each enclosure, and 
a monthly inspection must be performed to confirm that any enclosure 
openings that were closed during the performance test remain closed.
    To ensure continuous compliance with the requirement of no 
detectable leaks from the enclosure and closed-vent system, monitoring 
with a portable hydrocarbon detector is required to be performed 
initially along with a program of annual visible inspections of 
ductwork, piping, and connections to covers for evidence of visible 
defects. If visible defects in the closed-vent system are observed, 
readings greater than 500 ppm by volume above background are measured, 
or enclosure openings do not have negative pressure, a first effort to 
repair the closed-vent system must be made as soon as practicable and 
no later than 5 calendar days after identification of the problem. The 
repair must be completed no later than 15 calendar days after 
identification.
    To ensure the control device is not being bypassed if bypass lines 
are present, owners or operators must install, calibrate, maintain, and 
operate according to manufacturer's instructions a flow indicator that 
provides a record of emission point gas stream flow at least once every 
15 minutes. As an alternative, the proposed rule allows bypass lines to 
be sealed in the closed position and visually inspected to ensure they 
are being maintained in the closed position. The use of flow indicators 
or seals on the bypass lines ensures that process vent streams are 
continuously being routed to the control device.
4. Control Device Monitoring
    The purpose of enhanced monitoring is to provide a means for major 
sources to demonstrate that the affected facility is in continuous 
compliance with the standards. In light of these requirements, the EPA 
has considered how sources subject to the NSPS would demonstrate 
continuous compliance with standards for SOCMI process unit wastewater.
    The EPA considered three monitoring options for control devices: 
(1) the use of continuous emission monitors (CEMS) to measure total 
VOC; (2) the use of CEMS for surrogate compounds such as total 
hydrocarbons (THC) as surrogate for total VOC; or (3) the continuous 
monitoring of control device operating parameters.
    The first two options were determined to be unreasonable for this 
industry as discussed below. Although continuous emission monitors for 
total VOC are currently available, these devices are not universally 
applicable within this source category. Current emission monitoring 
systems that measure VOC emissions operate by flame ionization 
detection (FID), photoionization detection (PID), non-dispersive 
infrared (NDIR) absorption, or other detection principles that respond 
to VOC levels. However, in most cases, VOC monitors provide only a 
measure of the relative concentration level of a mixture of organics, 
rather than quantification of the organic species present. This trait 
necessitates the use of VOC CEMS more as a relative indicator rather 
than as a conventional emission monitor. Cases where it is possible to 
consider the VOC monitor as a conventional CEMS are, for the most part, 
limited to instances where only one organic species is present or where 
equal incremental amounts of each of the organic species present 
generate equal instrument responses. These instances are very unlikely 
to occur at SOCMI process units.
    In addition, a CEMS system that uses gas chromatography to measure 
gaseous organic compound emissions may not be suitable for applications 
where the number of VOC compounds to be monitored exceeds five. (See 
proposed Performance Specifications 101 and 102, appendix A of 40 CFR 
part 64, October 22, 1993 at 58 FR 54648.) However, SOCMI wastewaters 
can be expected routinely to have multiple chemical constituents with 
variable concentrations. Under these conditions, implementation of a 
CEMS system would be a costly undertaking. Furthermore, parametric 
monitoring has been demonstrated to be an effective means of indicating 
continuous compliance. Therefore, because a CEMS requirement would 
place an extra burden on the industry without increasing the accuracy 
of compliance demonstrations, the first two options were determined to 
be unreasonable. Owners or operators using control devices (e.g., 
incinerators or condensers) to comply with the proposed standards may 
use CEMS where applicable to demonstrate continuous compliance. 
However, parameter monitoring is also allowed if control devices are 
used. The Agency has selected temperature as the operating parameter 
that would then be monitored to determine ongoing compliance with the 
standard. For example, owners or operators of incinerators would have 
to monitor the combustion temperature (or the temperature before and 
after the catalyst bed if a catalytic incinerator is used), and owners 
or operators of condensers would have to monitor the temperature of the 
vapor exhaust stream.
    The use of CEMS on control devices is not proposed to be required 
for the following reasons:
    (1) CEMS cannot accurately determine compliance for many SOCMI 
wastewaters;
    (2) For each of these control systems a measurable control device 
parameter (e.g., temperature) is considered to provide a suitable 
indication of performance for determining compliance; and
    (3) Temperature monitors are considerably less costly than CEMS.
    The proposed standards, therefore, would be based on parameter 
monitoring to demonstrate compliance with the standards for control 
devices. The Agency is soliciting comments on the selection of 
temperature as a parameter to monitor for compliance and any available 
data on the correlation of the control device parameter to the control 
efficiency. The proposed rule would not preclude owners or operators 
who are using control devices to comply with the rule from choosing to 
use CEMS to demonstrate compliance.
    The continuous monitoring of control device operating parameters, 
established during the performance test or specified through design, is 
used to determine whether continuous compliance is achieved. Failure to 
maintain the established values for these parameters would be an 
enforceable violation of the emission limits of the proposed standards. 
Some of the process parameters are already monitored as part of normal 
operation. Therefore, continuous compliance is assured without imposing 
an additional unnecessary burden on the facility.
    In the proposed rule, enhanced monitoring is only applicable to 
control devices used to meet the requirements of the regulation. 
However, the EPA fully intends to make this rule consistent with other 
enhanced monitoring requirements. Therefore, the EPA is soliciting 
comments on the extent the enhanced monitoring requirements in the 
proposed rule are sufficient to meet the overall requirements of the 
Agency with regard to enhanced monitoring under section 114(a) of the 
CAAA or are additional requirements needed within the rule to meet the 
requirements of the CAAA.

J. Performance Test Methods

    Test methods and procedures are required to ensure compliance with 
the proposed standards, which include requirements for demonstrating 
that an emission point or process unit wastewater stream does not 
require control or that it is in compliance with the control 
requirements. Requirements to test for no detectable leaks from control 
devices, enclosure and closed-vent systems, and process wastewater 
collection and treatment systems are also included.
1. Wastewater Concentration and Flow Determination
    The standards require the use of approved test methods and 
procedures to ensure consistent and verifiable results for 
demonstration that a wastewater stream does not require control, or for 
demonstration that the allowed emission levels are achieved when 
controls are applied. Affected wastewater streams are subject to the 
standards if they meet either of the following conditions at the point 
of generation:
    (1) The average flow rate of the affected wastewater stream is 1.0 
Lpm or greater and the mass-weighted average volatile organic 
concentration is 500 ppmw or greater; or
    (2) The mass-weighted average volatile organic concentration of the 
affected wastewater stream is 10,000 ppmw or greater, regardless of the 
stream flow rate.
    Two important parameters must be quantified to determine whether an 
affected stream must be controlled. These parameters are the annual 
wastewater quantity for a stream and the volatile organic concentration 
of the stream at the point of generation.
    Several methods can be used to determine wastewater quantity. These 
methods include using knowledge about the capacity of the wastewater-
generating process or the waste management unit, and using measurements 
that are representative of maximum annual wastewater generation rates. 
Knowledge-based methods are allowed to provide flexibility and to 
provide less expensive alternatives than actual annual measurement if 
the appropriate information is available.
    For quantifying the volatile organic concentration of the 
wastewater streams, three methods are available: (1) Knowledge of the 
wastewater streams; (2) bench scale or pilot scale test data; or (3) 
physical measurements of volatile organic concentration. These methods 
have been allowed to provide flexibility and to provide less expensive 
alternatives than actual measurement if the appropriate information is 
available.
    If the actual volatile organic concentration of the wastewater 
stream is determined through direct measurement, the regulation 
specifies that the procedures of Method 25D in appendix A of part 60, 
``Determination of the Volatile Organic Concentration of Waste 
Samples,'' which provides a relative measure of the emissions potential 
of the stream, be used to analyze the sample. Alternatively, the sample 
may be analyzed to determine the volatile organic concentration using 
any test method or test data that has been validated according to the 
protocols in Method 301 in appendix A of part 63. As pointed out in 
section II of this document, there are several issues associated with 
the use of method 25D on which the EPA is soliciting comment.
    Flow rates may be determined using information about the maximum 
annual production capacity of the process unit, knowledge of the 
process, and mass balance information or by measuring the flow rate at 
the point of generation during conditions that are representative of 
average wastewater generation rates.
2. Performance Tests
    The initial performance test requirements of section 60.8 of the 
part 60 General Provisions are not required for treatment processes or 
vent stream control devices. Instead, the proposed standards provide 
alternative means of compliance that the EPA considers equivalent to 
the direct measurement of emissions as required under Sec. 60.8 and 
less burdensome to the industry.
    The proposed rule includes treatment process performance test 
procedures for the effluent concentration, percent reduction, and 
required mass removal standards. These test procedures involve 
measurements of volatile organic concentrations using Method 25D or any 
other methods for which the results are validated using Method 301. 
Performance testing is to be conducted at representative inlet flow 
rates and at volatile organic concentrations under which it would be 
most difficult to determine compliance.
    For noncombustion treatment processes complying with the percent 
reduction requirement, the total volatile organic mass flow rate 
entering the treatment process and exiting the treatment process shall 
be determined by computing the product of the average flow rate of the 
wastewater stream entering or exiting the treatment process and the 
average total volatile organic concentration of the entering or exiting 
wastewater streams, respectively. The flow rate of the entering and 
exiting wastewater streams shall be determined using the inlet and 
outlet flow meters, respectively.
    For combustion treatment processes complying with the percent 
reduction requirement, the total volatile organic mass flow rate 
entering the combustion unit shall be determined by computing the 
product of the average flow rate of the wastewater stream entering the 
combustion unit, as determined by the inlet flow meter, and the average 
total volatile organic concentration in the waste stream entering the 
combustion device. The volume exhausted shall be determined using 
Method 2, 2A, 2C, or 2D of 40 CFR part 60, appendix A, as appropriate. 
The average total organic concentration in the exhaust downstream of 
the combustion unit shall be determined using Method 18 of appendix A 
of part 60, or any other test method validated according to the 
procedures in Method 301 of appendix A of part 63.
    A performance test to demonstrate compliance of a vent stream 
control device with the organic compound reduction efficiency 
requirement shall use Method 1 or 1A of 40 CFR part 60, appendix A, as 
appropriate, to select sampling sites. The mass flow rate of organics 
entering and exiting the control device shall be determined by using 
Method 2, 2A, 2C, or 2D of appendix A of part 60, as appropriate, to 
determine the volume exhausted and by using Method 18 of appendix A of 
part 60, or any other test method validated according to the procedures 
in Method 301 of appendix A of part 63, to determine total organic 
concentration.
    A performance test to demonstrate compliance with the mass removal 
provision shall consist of a determination of mass removal required to 
be achieved and a determination of mass removal actually achieved. The 
total required mass removal is calculated by adding together the 
required mass removal for each individual affected stream to be 
combined for treatment. The required mass removal for each affected 
wastewater stream prior to combination of the streams for treatment 
shall be determined using the wastewater average flow rate and volatile 
organic average concentration at the point of generation for each 
affected wastewater stream to be combined for treatment. The actual 
total volatile organic mass removal in the wastewater stream shall be 
determined using the same procedures as described for noncombustion 
treatment processes complying with the percent reduction requirement.
    Finally, a performance test to demonstrate compliance of a 
biological treatment process with the 95-percent mass reduction 
requirement must be conducted using the procedures specified in the 
proposed rule. The control efficiency of the biological treatment unit 
is a function of the fraction biodegraded in a properly operated 
biological treatment unit. This fraction shall be determined using the 
procedures in appendix C of 40 CFR part 63.
    A performance test is not specified for the design steam stripper; 
installation of the specified equipment, along with monitoring to show 
attainment of the specified operating parameter levels, demonstrates 
compliance with the equipment design and operation provisions.
    Each vapor collection system, closed-vent system, fixed roof, 
cover, or enclosure must be evaluated initially and at annual intervals 
using Method 21 of appendix A of part 60 to determine the presence of 
detectable emissions from leaks. Method 21 represents the best 
available method for detecting leaks from these sources.

K. Reporting and Recordkeeping Requirements

    The reporting requirements necessitated by the proposed standard 
are authorized by section 114 of the Act. In addition to the reporting 
and recordkeeping requirements specified in the part 60 General 
Provisions, the proposed standard would require the submittal of 
several types of reports. First, the part 60 General Provisions would 
require notification reports, which inform the Agency of facilities 
subject to the NSPS. These reports include notification of 
construction, anticipated and actual startup dates, and physical or 
operational changes. In addition to the information required by the 
General Provisions, owners or operators would be required to provide 
information with the notice of construction identifying the process 
unit and stream as well as a brief description of the intended 
treatment and/or control technology. As part of the notification of 
startup, sources would also be required to provide more detailed 
information on the waste stream and waste management units. For 
example, sources would provide information on the chemical 
manufacturing processes that are subject to the proposed rule, 
information on the intended compliance strategy, and any required 
control device parameter ranges, unless the parameter ranges have 
already been established in the operating permit.
    Reports of the required design analysis (for steam strippers) or of 
performance test results of emission control systems would be required 
as well. These reports show whether a facility is initially meeting the 
level of the standard. The proposed rule would override the General 
Provisions requirements for quarterly reports for excess emissions and 
monitoring systems performance. Instead, semi-annual reports would be 
required in the event of each control equipment failure or instance 
when monitored parameters are not within their established values. Each 
semi-annual report shall include the date of the inspection, 
identification of each waste management unit in which a control 
equipment failure was detected, description of the failure, and 
description of the nature of and date the repair was made. The semi-
annual report shall also contain information on monitoring results that 
exceed the boundaries established in the operating permit.
    Owners or operators are required to keep records of all reports 
submitted under the proposed rule, of all monitoring parameters, 
equipment inspections, and of the determination of volatile organic 
concentration and/or annual average flow rate using knowledge of the 
process. Records must be maintained for 5 years.

L. Solicitation of Comments

    The EPA seeks full public participation in arriving at its final 
decisions, and strongly encourages comments on all aspects of this 
proposal from all interested parties. Whenever applicable, full 
supporting data and detailed analysis should be submitted to allow the 
EPA to make maximum use of the comments. The Agency invites all parties 
to coordinate their data collection activities with the EPA to 
facilitate mutually beneficial and cost-effective data submissions. The 
EPA is interested in participating in study plans, data collection, and 
documentation. Please refer to the FOR FURTHER INFORMATION section at 
the beginning of this preamble for technical contacts at the EPA. All 
comments should be directed to the EPA Air Docket, Docket No. A-94-32 
(see ADDRESSES). Comments on this notice will be accepted to the date 
specified in DATES.
    In addition, the EPA particularly requests comments and data on the 
following issues:
    1. The proposed approach to reducing the burden on owners or 
operators of waste management units, treatment processes, or control 
devices that allows owners or operators to comply with the control 
requirements of the proposed SOCMI NSPS for these waste management 
units, treatment processes, or control devices by demonstrating 
compliance with the benzene waste operations NESHAP, the HON, or the 
RCRA air emission standards for hazardous waste treatment, storage, and 
disposal facilities;
    2. The EPA's proposed approach to identifying parameters that 
define process unit wastewater streams that do not require control, 
whether it is feasible to identify such streams in ways other than 
through concentration or flow rate cutoffs, and information for 
defining such streams;
    3. The selection of temperature as a control device parameter to 
monitor to demonstrate compliance with the control device standards, 
and the correlation between temperature and the control efficiency, 
especially for regenerable activated carbon adsorption systems; and
    4. The inclusion of maintenance wastewater as part of the scope of 
the proposed standards and any barriers to the control of maintenance 
wastewater streams that meet the concentration and flow criteria used 
to identify those streams that require control at new facilities.
    5. The accessibility of SOCMI monitoring data and periodic reports 
to the general public as required by section 114(c) of the CAAA.
    6. The extent the enhanced monitoring requirements in the proposed 
rule are sufficient to meet the general requirements of the EPA for 
enhanced monitoring.
    7. The appropriateness of using method 25D and the resulting 
volatile organic concentration in the applicability and compliance 
determinations within the structure of the proposed regulation without 
discounting the non-VOC portion of the volatile organic concentration 
and also without eliminating low volatility compounds from test 
results.
    8. The relevance of including in the NSPS an alternative percent 
reduction compliance option for treatment processes that is based on 
the fraction removed by the design steam stripper for the individually 
speciated VOC.
    Commenters wishing to submit proprietary information for 
consideration should clearly distinguish such information from other 
comments, and clearly label it ``Confidential Business Information.'' 
Submissions containing such proprietary information should be sent 
directly to the contact person listed above, and not to the public 
docket. Information covered by such a claim of confidentiality will be 
disclosed by the EPA only to the extent allowed and by the procedures 
set forth in 40 CFR part 2. If no claim of confidentiality accompanies 
the submission when it is received by the EPA, it may be made available 
to the public without further notice to the commenter.

V. Administrative Requirements

A. Public Hearing

    A public hearing will be held, if requested, to discuss the 
proposed rule in accordance with section 307(d)(5) of the Act. Persons 
wishing to make an oral presentation on the proposed NSPS for SOCMI 
Wastewater should contact the EPA (see FOR FURTHER INFORMATION 
CONTACT). Oral presentations will be limited to 15 minutes each. Any 
member of the public may file a written statement before, during, or 
within 30 days after the hearing. Written statements should be 
addressed to the Air Docket Section (see ADDRESSES), and should refer 
to Docket No. A-94-32. A verbatim transcript of the hearing and any 
written statements will be available for public inspection and copying 
during normal working hours at the EPA's Air Docket Section (see 
ADDRESSES).

B. Administrative Designation and Regulatory Analysis

    Under Executive Order 12866 (58 FR 51735, October 4, 1993), the EPA 
must determine whether a regulation is ``significant'' and therefore 
subject to review by the Office of Management and Budget (OMB), and the 
requirements of the Executive Order. The order defines ``significant 
regulatory action'' as one that is likely to result in a rule that may: 
(1) Have an annual effect on the economy of $100 million or more or 
adversely affect in a material way the economy, a sector of the 
economy, productivity, competition, jobs, the environment, public 
health or safety, or State, local, or tribal governments or 
communities; (2) create a serious inconsistency or otherwise interfere 
with an action taken or planned by another agency; (3) materially alter 
the budgetary impact of entitlements, grants, user fees, or loan 
programs or the rights and obligations of recipients thereof; or (4) 
raise novel legal or policy issues arising out of legal mandates, the 
President's priorities, or the principles set forth in the Executive 
Order.
    This action was submitted to OMB for review. Changes made in 
response to OMB suggestions or recommendations are documented in the 
public record.

C. Compliance With Regulatory Flexibility Act

    Under section 605 of the Regulatory Flexibility Act of 1980 (5 
U.S.C. 601 et seq.), federal agencies are required to assess the 
economic impact of federal regulations on small entities. The Act 
specifically requires the completion of a Regulatory flexibility 
Analysis in those instances where small business impacts are possible. 
Because the impact of the proposed rule on all entities is likely to be 
insignificant in terms of changes in industry output, changes in 
expansion plans, and employment loss, it is reasonable to conclude that 
small entities, regardless of their number, are not significantly 
affected. Therefore, because these standards impose no adverse economic 
impacts, a Regulatory Flexibility Analysis has not been conducted.
    Pursuant to the provisions of 5 U.S.C. 605(b), I hereby certify 
that this rule, if promulgated, will not have a significant economic 
impact on a substantial number of small entities.

D. Paperwork Reduction Act

    The information collection requirements for this proposed rule have 
been submitted for approval to the Office of Management and Budget 
(OMB) under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. An 
Information Collection Request (ICR) document has been prepared by the 
EPA (ICR No. 1697.01), and a copy may be obtained from Sandy Farmer, 
Information Policy Branch (2136), U.S. Environmental Protection Agency, 
401 M Street, SW., Washington, DC 20460, or by calling (202) 260-2740.
    The public recordkeeping and reporting annual burden for this 
collection of information is estimated to average 13 hours per response 
for reporting and 203 hours per respondent for recordkeeping. These 
estimates include time for reviewing instructions, searching existing 
data sources, gathering and maintaining the data needed, and completing 
and reviewing the collection of information.
    Send comments regarding the burden estimate or any other aspect of 
this collection of information, including suggestions for reducing this 
burden, to Chief, Information Policy Branch (2136), U.S. Environmental 
Protection Agency, 401 M Street, SW.; Washington, DC 20460; and to the 
Office of Information and Regulatory Affairs, Office of Management and 
Budget, Washington, DC 20503, marked ``Attention: Desk Officer for 
EPA.'' Responses to any OMB or public comments on the information 
collection requirements contained in this proposal will accompany the 
final rule.

List of Subjects in 40 CFR Part 60

    Environmental protection, Air pollution control, Reporting and 
recordkeeping requirements, Volatile organic compounds.

    Statutory Authority: The statutory authority for this proposal 
is provided by sections 101, 111, 114, 116, and 301 of the Clean Air 
Act, as amended; 42. U.S.C., 7401, 7411, 7414, 7416, and 7601.

    Dated: August 31, 1994.
Jonathan Z. Cannon,
Acting Administrator.
[FR Doc. 94-22133 Filed 9-9-94; 8:45 am]
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