[Federal Register Volume 67, Number 100 (Thursday, May 23, 2002)]
[Proposed Rules]
[Pages 36460-36473]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-12845]



[[Page 36459]]

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Part V





Environmental Protection Agency





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40 CFR Part 63



National Emission Standards for Hazardous Air Pollutants: Municipal 
Solid Waste Landfills; Proposed Rule

  Federal Register / Vol. 67, No. 100 / Thursday, May 23, 2002 / 
Proposed Rules  

[[Page 36460]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[AD-FRL-7215-5]
RIN 2060-AH13


National Emission Standards for Hazardous Air Pollutants: 
Municipal Solid Waste Landfills

AGENCY: Environmental Protection Agency (EPA).

ACTION: Supplement to proposed rule.

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SUMMARY: This action is a supplemental proposal to the national 
emission standards for hazardous air pollutants (NESHAP) for municipal 
solid waste (MSW) landfills. On November 7, 2000, EPA proposed NESHAP 
for MSW landfills and requested comments on bioreactors. Based on 
comments to the proposed rule and additional information and analyses, 
EPA is adding a definition of bioreactors to the proposed rule and is 
proposing timely control for bioreactors located at MSW landfills with 
a design capacity greater than or equal to 2.5 million megagrams (Mg) 
and 2.5 million cubic meters (m3).

DATES: Comments. Comments are requested only on information and 
proposed requirements for bioreactors presented in this action. Submit 
comments on or before June 24, 2002. If a public hearing is held, 
written comments must be received by July 8, 2002.
    Public Hearing. If anyone contacts EPA requesting to speak at a 
public hearing by June 3, 2002, a public hearing will be held on June 
6, 2002.

ADDRESSES: Comments. By U.S. Postal Service, send comments (in 
duplicate if possible) to: Air and Radiation Docket and Information 
Center (6102), Attention Docket Number A-98-28, U.S. EPA, 1200 
Pennsylvania Avenue, NW., Washington DC 20460. In person or by courier, 
deliver comments (in duplicate if possible) to: Air and Radiation 
Docket and Information Center (6102), Attention Docket Number A-98-28, 
U.S. EPA, 401 M Street, SW., Washington, DC 20460. The EPA requests a 
separate copy also be sent to the contact person listed below (see FOR 
FURTHER INFORMATION CONTACT).
    Public Hearing. If a public hearing is held, it will begin at 10 
a.m. and will be held at EPA's Office of Administration Auditorium in 
Research Triangle Park, North Carolina, or an alternate site nearby. 
You should contact JoLynn Collins, Waste and Chemical Processes Group, 
Emission Standard Division, U.S. EPA (C439-03), Research Triangle Park, 
NC 27711, telephone (919) 541-5671 to request a public hearing, to 
request to speak at a public hearing, or to find out if a hearing will 
be held.
    Docket. Docket No. A-98-28 for this regulation and associated 
Docket No. A-88-09 contain supporting information used in developing 
the standards. These dockets are located at the U.S. EPA, 401 M Street 
SW, Washington, DC 20460, in Room M-1500, Waterside Mall (ground floor, 
central mall), and may be inspected from 8:30 a.m. to 5:30 p.m., Monday 
through Friday, excluding legal holidays. Copies of docket materials 
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: Ms. Michele Laur at Waste and Chemical 
Processes Group, Emission Standards Division (C439-03), Office of Air 
Quality Planning and Standards, U.S. EPA, Research Triangle Park, NC 
27711, telephone number (919) 541-5256, facsimile number (919) 541-
0246, electronic mail address ''[email protected].''

SUPPLEMENTARY INFORMATION: Comments. Comments and data may be submitted 
by electronic mail (e-mail) to: [email protected]. Electronic 
comments must be submitted as an ASCII file to avoid the use of special 
characters and encryption problems. Comments will also be accepted on 
disks in WordPerfect file format. All comments and 
data submitted in electronic form must note the docket number: (Docket 
No. A-98-28). No confidential business information (CBI) should be 
submitted by e-mail. Electronic comments may be filed online at many 
Federal Depository Libraries.
    Commenters wishing to submit proprietary information for 
consideration must clearly distinguish such information from other 
comments and clearly label it ''Confidential Business Information.'' 
Send submissions containing such proprietary information directly to 
the following address, and not to the public docket, to ensure that 
proprietary information is not inadvertently placed in the docket: 
Attention Ms. Michele Laur, c/o OAQPS Document Control Officer (C404-
02), U.S. EPA, Research Triangle Park, NC 27711.
    The EPA will disclose information identified as CBI only to the 
extent allowed and by the procedures set forth in 40 CFR part 2. If no 
claim of confidentiality accompanies a submission when it is received 
by the EPA, the information may be made available to the public without 
further notice to the commenter.
    Public Hearing. Persons interested in presenting oral testimony or 
inquiring as to whether a hearing is to be held should contact Ms. 
JoLynn Collins at the Emission Standards Division (C439-03), U.S. EPA, 
Research Triangle Park, North Carolina 27711, telephone (919) 541-5671, 
at least 2 days in advance of the public hearing. Persons interested in 
attending the public hearing must also call Ms. Collins to verify time, 
date, and location of the hearing. The public hearing will provide 
interested parties the opportunities to present data, views, or 
arguments concerning this supplemental proposal.
    Docket. The docket is an organized an complete file of all the 
information considered by the EPA in the development of this 
rulemaking. The docket is a dynamic file because material is added 
throughout the rulemaking process. The docketing system is intended to 
allow members of the public and industries involved to readily identify 
and locate documents so that they can effectively participate in the 
rulemaking process. Along with the proposed and promulgated standards 
and their preambles, the contents of the docket will serve as the 
record in the case of judicial review. (See section 307(d)(7)(A) of the 
Clean Air Act (CAA).) The regulatory text and other materials related 
to this rulemaking are available for review in the docket, or copies 
may be mailed on request from the Air Docket by calling (202) 260-7548. 
A reasonable fee may be charged for copying docket materials.
    World Wide Web (WWW). In addition to being available in the docket, 
an electronic copy of today's supplemental proposal will also be 
available on the WWW through the Technology Transfer Network (TTN). 
Following signature, a copy of today's supplemental proposal will be 
posted on the TTN's policy and guidance page for newly proposed or 
promulgated rules at the following address: http://www.epa.gov/ttn/oarpg. The TTN provides information and technology exchange in various 
areas of air pollution control. If more information regarding the TTN 
is needed, call the TTN HELP line at (919) 541-5384.
    Regulated Entities. Categories and entities potentially regulated 
by this action:

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                                                                               Examples of potentially regulated
                 Category                     NAICS code         SIC code                   entities
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Industry: Air and water resource and                 924110              9511  Solid waste landfills.
 solid waste management.
Industry: Refuse systems-solid waste                 562212              4953  Solid waste landfills.
 landfills.
State, local, and Tribal government                  562212              4953  Solid waste landfills; Air and
 agencies.                                           924110                     water resource and solid waste
                                                                                management.
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    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be regulated by this 
action. To determine whether your facility would be regulated by this 
action, you should carefully examine the applicability criteria in 
 63.1935 and 63.1940 of the landfills proposed rule. 
If you have any questions regarding the applicability of this action to 
a particular entity, contact the person listed in the preceding FOR 
FURTHER INFORMATION CONTACT section.
    Outline. The information presented in this supplemental proposal is 
organized as follows:

I. Statutory Authority
    A. What is the source of authority for development of NESHAP?
    B. What criteria are used in the development of NESHAP?
II. Background
III. Summary of Supplemental Proposed Requirements for Bioreactors
IV. Rationale for the Proposed Requirements for Bioreactors
    A. Why is EPA proposing supplemental requirements for 
bioreactors at MSW landfills?
    B. How did EPA determine the bioreactor portion of the MSW 
landfill MACT floor?
    C. How did EPA consider beyond-the-floor options?
    D. How did EPA determine the standard for bioreactor operations 
at area source MSW landfills?
    E. What is EPA's rationale for the specific requirements for 
bioreactors?
    F. What other issues did EPA consider?
V. Summary of Environmental, Energy, and Economic Impacts of the 
Proposed Requirements for Bioreactors
VI. Administrative Requirements
    A. Executive Order 12866, Regulatory Planning and Review
    B. Executive Order 13132, Federalism
    C. Executive Order 13175, Consultation and Coordination with 
Indian Tribal Governments
    D. Executive Order 13045, Protection of Children from 
Environmental Health Risks and Safety Risks
    E. Executive Order 13211, Actions Concerning Regulations that 
Significantly Affect Energy Supply, Distribution, or Use
    F. Unfunded Mandates Reform Act of 1995
    G. Regulatory Flexibility Act (RFA), as Amended by the Small 
Business Regulatory Enforcement Fairness Act of 1996 (SBREFA), 5 
U.S.C. 601 et seq.
    H. Paperwork Reduction Act
    I. National Technology Transfer and Advancement Act

I. Statutory Authority

A. What Is the Source of Authority for Development of NESHAP?

    Section 112 of the CAA requires us to list categories and 
subcategories of major sources and area sources of hazardous air 
pollutants (HAP), and to establish NESHAP for the listed source 
categories and subcategories. The category of major sources covered by 
today's supplemental proposal was on our initial list of HAP emission 
source categories as published in the Federal Register on July 16, 1992 
(52 FR 31576). For ''major'' source MSW landfills (those that have the 
potential to emit 10 tons per year (tpy) of any one HAP or 25 tpy of 
any combination of HAP), the CAA requires us to develop standards that 
require the application of maximum achievable control technology 
(MACT).
    Under section 112(k) of the CAA, EPA developed a strategy to 
control emissions of HAP from area sources in urban areas, identifying 
33 HAP that present the greatest threat to public health in the largest 
number of urban areas as the result of emissions from area sources. 
Municipal solid waste landfills were listed as one of the 29 area 
source categories on July 19, 1999 (64 FR 38706) because 13 of the 
listed HAP are emitted from MSW landfills.

B. What Criteria Are Used in the Development of NESHAP?

    Section 112 of the CAA requires that we establish NESHAP for the 
control of HAP from both new and existing major sources. The CAA 
requires the NESHAP to reflect the maximum degree of reduction in 
emissions of HAP that is achievable. This level of control is commonly 
referred to as the MACT.
    The MACT floor is the minimum control level allowed for NESHAP and 
is defined under section 112(d)(3) of the CAA. In essence, the MACT 
floor ensures that the standard is set at a level that assures that all 
major sources achieve the level of control at least as stringent as 
that already achieved by the better-controlled and lower-emitting 
sources in each source category or subcategory. For new sources, the 
MACT floor cannot be less stringent than the emissions control that is 
achieved in practice by the best-controlled similar source. The MACT 
standards for existing sources can be less stringent than standards for 
new sources, but they cannot be less stringent than the average 
emissions limitation achieved by the best-performing 12 percent of 
existing sources in the category or subcategory (or the best-performing 
five sources for categories or subcategories with fewer than 30 
sources).
    In developing MACT, we also consider control options that are more 
stringent than the floor. We may establish standards more stringent 
than the floor based on the consideration of cost of achieving the 
emissions reductions, any non-air quality health and environmental 
impacts, and energy requirements.
    Finally, the CAA allows NESHAP to reflect an alternative standard 
for area sources. The alternative standard provides for the use of 
generally available control technologies (GACT) or management practices 
to reduce emissions of HAP.

II. Background

    On November 7, 2000, we proposed NESHAP for MSW landfills (65 FR 
66680). When final, the rule will fulfill the requirements of section 
112(d) of the CAA, which requires the Administrator to regulate 
emissions of HAP, and help implement the Urban Air Toxics Strategy 
developed under section 112(k) of the CAA.
    In the November 7, 2000 proposed landfills NESHAP, we described 
differences in emissions rates over time from landfills operated as 
bioreactors as opposed to conventional landfills. We also requested 
additional information on emissions from bioreactors. We solicited 
comments on requiring installation of collection and control systems 
sooner after waste is deposited in bioreactor cells.
    We received five public comments addressing bioreactors. The 
commenters agreed that because of the enhanced biodegradation of waste 
in bioreactors, they generate landfill gas, including organic HAP, at 
higher rates soon after waste placement. The industry commenters stated 
that research is ongoing and there is insufficient information to 
precisely estimate emissions from bioreactors. They recommended timely 
collection and

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control of bioreactors, but strongly suggested that EPA issue guidance 
rather than rules until additional data are collected. Other commenters 
representing State agencies commented that many bioreactors had 
installed collection and control systems prior to initiating liquids 
addition, and that the landfills NESHAP should require installation of 
collection and control systems prior to initiating liquids addition for 
all bioreactors, regardless of landfill size.
    We reviewed the public comments and other recent literature. We 
also gathered additional information on the number of bioreactors, 
their control levels, and the timing of collection and control system 
installation. This supplemental proposal describes the available 
information, presents a supplement to the November 7, 2000 proposed 
landfills NESHAP, and describes the rationale for the proposed 
supplemental requirements. The additional information and analyses are 
contained in Docket No. A-98-28.

III. Summary of Supplemental Proposed Requirements for Bioreactors

    We are proposing timely installation of collection and control 
systems in bioreactors located at landfills with a total landfill 
design capacity of greater than or equal to 2.5 million Mg and 2.5 
million m\3\. These requirements would apply to bioreactors within 
landfills at both major and area sources if the landfills meet the 
design capacity criteria. The proposed supplemental control 
requirements apply only to active landfills (i.e., existing and new 
landfills that are still accepting waste as of the date of publication 
of the final rule or have the capacity to accept additional waste and 
are not permanently closed). The requirements would not apply to 
bioreactors at permanently closed landfills.
    The supplemental proposal would require the same level of control 
for the bioreactor portions of landfills as would be required in the 
proposed landfills NESHAP (65 FR 66680, November 7, 2000) for 
conventional MSW landfills (i.e., a well-designed and operated gas 
collection system and a control device achieving 98 percent reduction 
or 20 parts per million by volume (ppmv) of nonmethane organic 
compounds (NMOC) as is required in the final new source performance 
standards/emission guidelines (NSPS/EG) at 40 CFR part 60, subparts Cc 
and WWW. However, if you own or operate a bioreactor at a landfill that 
is a new affected source, then you would be required to install the gas 
collection and control system in the bioreactor prior to initiating 
liquids addition, regardless of whether the landfill emissions rate 
equals or exceeds the 50 Mg/yr emissions rate criteria in the NSPS/EG. 
Startup of the collection and control system would be required within 
90 days after initiating liquids addition. If the bioreactor is located 
at a landfill that is an existing affected source, then you must 
install and begin operating a collection and control system for the 
bioreactor within 3 years after publication of the final landfills 
NESHAP unless earlier control is already required by the NSPS/EG. You 
would be required to conduct a performance test and report the results 
within 180 days after startup of the bioreactor collection and control 
system.
    The proposed timing for extending the collection and control system 
into new cells or areas of the bioreactor is also different from 
conventional landfills. Once control of your bioreactor is required, 
you would need to install collection and control systems in new areas 
or cells of the bioreactor prior to initiating liquids addition to that 
area, cell, or group of cells. Under the supplemental proposal, 
controls could be removed from the bioreactor portion of the landfill 
either: (1) When the criteria for control removal specified in the 
landfills NSPS/EG are met; or (2) when the bioreactor is permanently 
closed, liquids addition has ceased, and liquids have not been added to 
the bioreactor for at least 1 year.
    At some landfills, a portion of the landfill is a bioreactor, and 
the remainder is designed and operated as a conventional landfill. In 
these situations, the control requirements and the timing of control 
installation for the conventional portion of the landfill would not 
change. We are not proposing to revise the NSPS/EG. Thus, you would 
continue to use the equations and factors in the NSPS/EG to calculate 
the annual uncontrolled NMOC emissions rate for your landfill as a 
whole (including the total waste placed in the bioreactor area and the 
conventional area). When your calculated uncontrolled NMOC emissions 
equal or exceed 50 Mg/yr, then you would install a collection and 
control system for the conventional portions of the landfill according 
to the schedule in the NSPS, or the applicable State, Tribal, or 
Federal plan that implements the EG.

IV. Rationale for the Proposed Requirements for Bioreactors

A. Why Is EPA Proposing Supplemental Requirements for Bioreactors at 
MSW Landfills?

    Based on review of public comments and other available information, 
we have concluded that bioreactors are a distinct operation within MSW 
landfills, and that the appropriate timing of control for bioreactors 
is different from that for conventional landfills. The design and 
method of operation of bioreactors is different from conventional 
landfills, resulting in different emissions characteristics.
    Conventional landfills are typically operated as ''dry tombs'' by 
minimizing the infiltration of liquids into the landfill. This can be 
accomplished by placement of bottom and side liners and by placement of 
a low permeability final cap over the waste. In addition, many sites 
install and operate leachate collection systems to remove leachate and 
thus minimize groundwater contamination. That method also results in a 
slower biodegradation process and a reduced rate of landfill gas 
generation. Some conventional landfills recirculate some or all of the 
collected leachate. A typical moisture content of the waste in a 
conventional landfill is approximately 20 percent, but it may be lower 
in arid areas or where all collected leachate is removed and 
infiltration is minimized.
    A bioreactor is defined as an MSW landfill or portion of an MSW 
landfill where any liquid other than leachate is added in a controlled 
fashion into the waste mass (often in combination with recirculating 
leachate) to reach a minimum average moisture content of at least 40 
percent by weight to accelerate or enhance the anaerobic (without 
oxygen) biodegradation of the waste. The minimum 40 percent moisture 
level is based on literature that suggests the moisture content of the 
waste should remain in the range of 40 to 70 percent to optimize 
bioreactor operation. Comments on the moisture level used in the 
bioreactor definition are requested. The EPA also requests comments on 
the proposed exclusion of the definition of landfills that recirculate 
leachate but do not add any other liquids. If you know of situations 
where leachate recirculation alone can reach a 40 percent moisture 
level and start and sustain bioreactor operation, please provide 
information.
    The proposed definition of bioreactor includes hybrid bioreactors, 
which are managed so that the waste undergoes a short (e.g., 60 day) 
aerobic stage, after which the waste is covered over and operated as an 
anaerobic bioreactor for

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several years. The long-term operation, emissions pattern, and 
applicable control techniques for hybrid bioreactors are similar to 
anaerobic bioreactors. The rapid biodegradation of waste in a 
bioreactor leads to more rapid generation of landfill gas compared to a 
conventional landfill.
    The vast majority of bioreactors are anaerobic or hybrid 
bioreactors, with at least 24 operating as of 2001. The EPA expects a 
large number of anaerobic bioreactors to start operation in the next 
few years because of their economic benefits and potential 
environmental benefits. For example, operating a landfill as a 
bioreactor extends the use of current sites and reduces the need for 
new sites, reducing land use and associated environmental impacts, and 
land purchase costs. Preliminary information suggests that bioreactors 
also improve the quality of leachate potentially resulting in reduced 
environmental impacts if any groundwater contamination were to occur. 
Economic benefits include avoiding the costs of leachate treatment, 
transport, and disposal. In addition, bioreactors emit a similar total 
amount of gas as conventional landfills but emit it more quickly over a 
shorter amount of time, thus owners and operators can convert landfill 
gas to energy more economically.
    Because of the rapid biodegradation of waste, landfill gas 
(including methane, NMOC, and organic HAP) is generated at a 
significantly greater rate in the first couple of years after waste 
placement in anaerobic and hybrid bioreactors compared to conventional 
landfills. For example, one study indicates that in approximately 90 
days, bioreactor landfills generate gas at a rate similar to what a 
conventional MSW landfill generates at 2 years. Public comments and 
published studies confirm the greater landfill gas generation rates 
early in the life of anaerobic and hybrid bioreactors. Emissions rates 
cited in the comments and literature range from 2 to 10 times as much 
as conventional landfills. After peaking at a higher generation rate 
near the time of landfill closure, bioreactor landfill gas generation 
declines more rapidly than conventional landfill gas generation. The 
total long-term amount of landfill gas from an anaerobic bioreactor is 
expected to be approximately the same as from a conventional landfill 
with the same amount of waste because the total potential landfill gas 
generation depends primarily on the amount of material in the waste 
that can eventually be decomposed. However, bioreactor landfill gas 
generation is significantly higher than conventional landfill gas 
generation prior to and shortly after closure and significantly lower 
in the later years. References indicate that a bioreactor shortens the 
period of waste degradation and stabilization, and thus the period of 
most of the gas generation, from 30 to 50 years for a conventional 
landfill to 5 to 10 years for an anaerobic bioreactor.
    Because bioreactors generate significantly more landfill gas, 
including organic HAP, earlier in their life than conventional 
landfills, the methods used in the proposed rule to calculate 
uncontrolled emissions and the required timing for collection and 
control system installation that apply to conventional landfills are 
not appropriate for bioreactors. The November 2000 proposed landfills 
NESHAP, which refer to the NSPS control requirements, would require 
landfills to estimate their NMOC emissions using specified equations 
and procedures. After landfills reach or exceed 50 Mg/yr of NMOC, they 
must install collection and control systems within 30 months. Gas 
collection must then be extended into each cell or area within the 
landfill within 2 years after waste is first placed in that cell or 
area if the area is at final grade or within 5 years if the area is 
still active.
    For bioreactors, the 50 Mg/yr NMOC uncontrolled emissions rate 
would be reached sooner than calculated by the procedures in the NSPS/
EG. Furthermore, because landfill gas generation rates from bioreactors 
are significantly higher in the early years after waste placement, 
allowing 30 months after uncontrolled estimated emissions reach 50 Mg/
yr to install controls would allow a much higher proportion of total 
bioreactor emissions, including HAP, to be released uncontrolled. 
Modeling of a landfill in a non-arid location with a design capacity of 
2.5 million Mg and a 20-year life indicates that the NSPS/EG Tier 1 
procedures would not require control installation for 5 years. In this 
time, a bioreactor accepting the same amount of waste would have 
potentially emitted a total of 130 Mg of HAP and 680 Mg of NMOC. (This 
is based on a k value of 0.1 for the bioreactor, which may be 
conservatively low, so bioreactor emissions could be higher.) If the 
same landfill were in an arid climate, Tier 1 procedures would not 
require control installation for 8 years. In this time, a bioreactor 
accepting the same amount of waste would have potentially emitted 310 
Mg of HAP and 1,600 Mg of NMOC. Due to the different emissions pattern 
of bioreactors, it is appropriate to require control at the start of 
bioreactor operation (initiation of liquids addition).
    The timing of control system removal for conventional landfills 
also may not be appropriate for bioreactor landfills. Because emissions 
decline more rapidly, a bioreactor would require control for a shorter 
length of time than a conventional landfill.
    Because of the differences in technical design, operation, and 
emissions pattern over time, we have examined bioreactors as a distinct 
type of operation within an MSW landfill affected source, evaluated the 
MACT floor and MACT for bioreactor operations within MSW landfills, and 
are proposing supplemental requirements for bioreactors.

B. How Did EPA Determine the Bioreactor Portion of the MSW Landfill 
MACT Floor?

    A landfill that is an affected source under the MSW landfills 
NESHAP may include an area designed and operated as a bioreactor and an 
area designed and operated as a conventional landfill. When there are 
distinct operations that have different emissions characteristics 
within an affected source, EPA often examines these operations 
separately in determining the MACT floor for the source as a whole. 
Details of the bioreactor analysis are contained in Docket No. A-98-28. 
The conventional landfill component of the MACT floor for existing 
landfills remains as described in the November 2000 proposed landfills 
NESHAP.
    First, we reviewed the information available to identify specific 
bioreactors, determined which are located at major sources, and 
determined the level of control and the timing of installation of 
control systems at these bioreactors. We then determined the control 
level for the average (or median) of the best-performing five 
bioreactors, because there are fewer than 30 bioreactors at MSW 
landfills that are major sources. Under the CAA, the MACT floor for 
existing sources is based on the best performing 12 percent of sources 
in a category, or the best five sources if there are fewer than 30 
sources in the category.
    Based on the available data, we identified 24 anaerobic 
bioreactors. We used information from the landfills NESHAP database and 
other data provided by contacts familiar with these landfills to 
determine which of the bioreactors are located at landfills with 
maximum uncontrolled emissions equal to or greater than major source 
levels for HAP. We used the population of ten bioreactors to determine 
the MACT floor for bioreactors. The population includes

[[Page 36464]]

both major and ''synthetic area'' sources. A synthetic area source is a 
source which would otherwise be a major source, if not for enforceable 
emissions controls that have been installed. For example, some 
landfills with uncontrolled emissions above major source levels have 
installed controls to comply with the landfills NSPS/EG. Synthetic area 
sources are included in the population used to determine the MACT floor 
because to exclude synthetic area sources from the MACT floor 
determination would exclude the best-controlled sources in the 
industry. The CAA does not suggest that we should exclude a control 
technology from consideration in the MACT floor because it is so 
effective that it reduces emissions from a source such that the source 
is no longer a major source of HAP.
    We identified the controls in use at the ten bioreactors with 
uncontrolled emissions at major source levels and determined the 
installation date for the controls. We found that all ten of the 
bioreactors have gas collection and control systems meeting the control 
levels in the NSPS/EG. We also found that at least five of the gas 
collection and control systems were installed or are being installed 
prior to initiating liquids addition to the bioreactors. The control 
systems were installed in the bioreactors sooner than required by the 
NSPS/EG. Therefore, we determined that the MACT floor level of control 
for bioreactor operations within existing MSW landfills at major 
sources is installation of a collection and control system that meets 
NSPS/EG requirements, and that these controls be installed prior to 
initiation of liquids addition.
    Under the CAA, the new source MACT floor is based on the best-
controlled similar source. We reviewed the information to determine the 
best control technology in use at the ten bioreactors at major and 
synthetic area sources, and we looked at when the control systems were 
installed. The best-controlled bioreactor installed a collection and 
control system that meets NSPS/EG requirements prior to initiation of 
liquids addition; therefore, this is the MACT floor level of control 
for bioreactor operations within new MSW landfills at major sources.

C. How Did EPA Consider Beyond-the-Floor Options?

    The NSPS/EG requirements for landfill gas collection and emissions 
reductions are the best available control for organic HAP emissions 
from bioreactors. Requiring control system installation before the 
initiation of liquids addition to the bioreactor is the earliest 
possible time to install these controls. Therefore, there were no 
options to consider that were more stringent than the MACT floor. The 
gas collection system required by the NSPS/EG (described in 40 CFR 
60.753) is designed to capture as much landfill gas as possible and 
requires several parameters to be monitored to ensure that capture, 
including pressure, nitrogen or oxygen concentration, temperature, and 
surface methane concentration. There are no data indicating that 
collection systems are in use that are more effective than those 
required by the NSPS/EG. Similarly, there are no known technologies 
that can regularly achieve organic HAP reduction efficiencies greater 
than those specified in the NSPS/EG. The NSPS/EG rules require 98 
percent reduction efficiency for NMOC, or a maximum outlet 
concentration of 20 ppmv if an enclosed combustion device is used. The 
reduction efficiencies can be regularly achieved by several types of 
control technologies with proper operation. Because there are no more 
stringent collection and control technologies or other emissions 
reduction techniques available, and this supplemental proposal requires 
installation and operation of the floor level of control as soon as 
possible, no options beyond-the-floor currently exist for new or 
existing sources.

D. How Did EPA Determine the Standard for Bioreactor Operations at Area 
Source MSW Landfills?

    As described earlier in this preamble, MSW landfills were listed as 
one of 29 area source categories under section 112(k) of the CAA. Area 
sources can be controlled using MACT or GACT. In the proposed landfills 
NESHAP (65 FR 66677, November 7, 2000), we concluded that GACT is the 
same as MACT (the NSPS/EG level of control) for area source landfills 
that meet the NSPS/EG design capacity and uncontrolled NMOC emissions 
rate criteria. We also found that landfills below these criteria do not 
warrant control.
    For the supplemental proposal, we have examined what constitutes 
GACT for area source bioreactors. We determined that for bioreactors at 
landfills with design capacities greater than or equal to 2.5 million 
Mg and 2.5 million m3, GACT is the same as MACT (i.e., 
timely installation of gas collection and control systems that meet 
NSPS/EG requirements). In reaching GACT decisions, we considered the 
control techniques that are generally available for area sources and 
factors such as the emissions reductions, environmental impacts, and 
costs of these controls. Since bioreactors generate landfill gas at a 
faster rate, significant HAP emissions reductions will be achieved by 
requiring timely control of bioreactor operations at MSW landfills with 
design capacities greater than or equal to 2.5 million Mg and 2.5 
million m3. The reductions in HAP will reduce health risks 
and environmental impacts associated with the HAP present in landfill 
gas.
    The costs of requiring timely control for bioreactor operations at 
area source landfills with design capacities equal to or greater than 
2.5 million Mg and 2.5 million m3 were also considered in 
reaching the decision that GACT is the same as MACT for these area 
sources. These landfills would, at some point in their life, be 
required to install controls required by the NSPS/EG because the 
estimated uncontrolled NMOC emissions rates would reach the 50 Mg/yr 
emissions rate criteria. Requiring timely control of bioreactor 
operations means that costs will be incurred sooner and emissions 
reductions benefits realized earlier. An analysis of net present value 
(NPV) costs shows that timely control of bioreactors at a landfill with 
a design capacity of 2.5 million Mg is generally not more costly than 
controlling a conventional landfill according to the NSPS/EG schedule. 
If the landfill gas is used for energy, the NPV control costs for 
bioreactors are lower than for conventional landfills and result in 
greater HAP emissions reductions. For these reasons, GACT for 
bioreactor operations at area source landfills with design capacities 
greater than or equal to 2.5 million Mg and 2.5 million m3 
was determined to be the same as MACT.
    For bioreactor operations at area source landfills with design 
capacities less than 2.5 million Mg or 2.5 million m3, EPA 
determined that GACT does not require control. Requiring bioreactors at 
landfills below the design capacity cutoff to install controls would 
result in additional control costs because they are not otherwise 
required to install control by the NSPS/EG. The 2.5 million Mg and 2.5 
million m3 capacity exemption excludes those landfills that 
can least afford the costs of collection and control systems, including 
small businesses and, particularly, municipalities. Furthermore, the 
analysis for the NSPS/EG found that a more stringent design capacity 
exemption level would greatly increase the number of landfills required 
to apply control while only achieving 25 percent additional emissions 
reductions. The selected design capacity criteria required control

[[Page 36465]]

of less than 5 percent of all landfills (at the time of the NSPS/EG 
promulgation), but reduced NMOC emissions by approximately 53 percent. 
While bioreactors have a significantly increased landfill gas 
generation rate early in their life, it is expected that their overall 
lifetime total landfill gas generation potential would not be 
significantly greater than that of a conventional landfill accepting 
the same amount of waste. Therefore, the previous analyses of potential 
long-term emissions reductions from control of small landfills would 
also apply to bioreactors based on data currently available on 
bioreactor operations. We request comment on exemption of small/area 
source landfills with bioreactor operations from this supplemental 
proposal. If information is submitted that shows these small/area 
source landfills with bioreactor operations have emission 
characteristics that are significantly different than conventional 
small/area source landfills, the data will be considered.
    Other reasons for exempting small landfills are described in the 
proposed landfills NESHAP (65 FR 66677, November 7, 2000), and they 
also apply to bioreactors. For example, most existing area source 
landfills are closed, and their emissions are already declining. Most 
newer landfills are much larger than the design capacity cutoff and 
would be subject to the GACT control requirements. Therefore, requiring 
timely control of bioreactor operations at these large, open landfills 
would achieve significant HAP reductions at those landfills where it 
will be most cost effective.

E. What Is EPA's Rationale for the Specific Requirements for 
Bioreactors?

1. How Did EPA Select the Affected Source?
    Selection of the affected source defines the boundary of the unit 
to which a proposed rule applies. This definition is used in 
combination with the date ''construction'' or ''reconstruction'' is 
''commenced,'' as defined in 40 CFR 63.2, to determine whether an 
affected source is an existing source or a new source.
    The supplemental proposal would not substantially alter the 
affected source definition in the November 7, 2000 proposed landfills 
NESHAP. The affected source for the proposed landfills NESHAP remains 
the entire municipal solid waste landfill. The bioreactor is not a 
separate affected source, but is an operation within the affected 
source (the landfill). Defining the affected source broadly maintains 
consistency with the NSPS/EG and the proposed landfills NESHAP. As 
defined in section 112 of the CAA, a new source is one that commences 
construction or reconstruction after the Administrator first proposes 
NESHAP applicable to a source. Therefore, a bioreactor is subject to 
the new source requirements if the landfill where it is located 
commences construction or reconstruction after November 7, 2000, the 
date of the original proposal. A bioreactor is subject to the existing 
source requirements if the landfill where it is located commenced 
construction or reconstruction on or before that date. The definition 
of new and existing source is consistent with the definition in the 
November 7, 2000 proposed landfills NESHAP. Note that the control 
requirements for bioreactors at new and existing sources are the same, 
but the initial compliance date is different.
2. How Did EPA Determine When Collection and Control Systems Must Be 
Installed and When They Must Start Operation?
    For bioreactors that are located at landfills that are new affected 
sources, the proposed changes would require gas collection and control 
systems to be installed in the bioreactor prior to liquids addition 
because this has been determined to be the MACT and GACT level of 
control for bioreactors at landfills with design capacities greater 
than or equal to 2.5 million Mg and 2.5 million m3. However, 
it may not be feasible to begin operation of the control system on the 
day that liquids addition begins. It can take a few weeks for the 
biodegradation process to generate large amounts of gas, for the gas 
flow and composition to stabilize, to tune the gas collection system, 
and to achieve stable operation of a combustion control device. In 
recognition of this time period, we propose to require that bioreactor 
gas collection and control systems begin operation within 90 days after 
the first date of liquids addition. Bioreactors have been able to begin 
operation of control systems on this schedule. Furthermore, studies 
indicate that after 90 days of operation, a bioreactor may generate as 
much landfill gas as a conventional landfill does in 2 years of 
operation. The NSPS/EG and the November 7, 2000 proposed landfills 
NESHAP require gas collection and control systems to be installed and 
begin operation in new cells or areas of a controlled conventional 
landfill within 2 years after waste is first placed in that cell or 
area for areas that are at final grade (5 years for active areas that 
are still accepting waste). Since bioreactors may reach similar gas 
flows in 90 days, it is consistent to require the control system in the 
bioreactor to begin operation within 90 days of liquids addition.
    Bioreactors that are located at landfills that are existing 
affected sources will need time to design and install a control system. 
For these bioreactors, we propose to allow 3 years from the date the 
final landfills NESHAP are published to install and begin operating a 
collection and control system. This allows time for the bioreactor 
owner/operator to design, install, and begin operating the gas 
collection and control system. The 3-year period is consistent with the 
maximum time section 112 of the CAA allows for existing sources to 
achieve compliance with NESHAP. Note that if an existing source 
landfill is required by the NSPS/EG to install control in a bioreactor 
before the 3-year date, the supplemental proposal would not change the 
control installation date.
    If an existing source landfill installs and begins to operate a 
bioreactor at a date later than 3 years after the final landfills 
NESHAP are published, then a collection and control system for the 
bioreactor would be required to be installed before the initiation of 
liquids addition. The control system would be required to begin 
operation within 90 days after the first date of liquids addition. The 
control system installation date is consistent with the CAA section 112 
requirements that existing sources must be in compliance by 3 years 
after the effective date of the rule and must maintain continuous 
compliance after that date. It is also consistent with the findings of 
the MACT floor determination that the best performing existing sources 
control bioreactors from the time they initiate liquids addition. It is 
also reasonable because existing source landfills that choose to begin 
operating bioreactors more than 3 years in the future will know the 
bioreactor control requirements and will have sufficient time to plan 
for compliance by the date they initiate liquids addition. The 
requirement to begin operating the bioreactor control system within 90 
days of initiating liquids addition is based on the rationale described 
in the previous paragraph for new sources.
    An initial performance test to demonstrate compliance with the 
emissions limits would be conducted, and the results submitted within 
180 days after the date the collection and control system must begin 
operation. This 180-day time period is generally consistent with the 
performance test requirements for conventional landfills

[[Page 36466]]

in the November 7, 2000 proposed landfills NESHAP and the NSPS/EG.
    As with conventional landfills, as one area of the bioreactor is 
filled to capacity, waste will be placed in new cells or areas of the 
bioreactor over time. Conventional landfills must extend collection and 
control systems into new cells or areas of the landfill within 2 years 
of when waste is first placed in that area for areas that are at final 
grade, or within 5 years of when the waste is first placed in that area 
for active areas that are still accepting waste. For bioreactors, we 
propose that starting on the date control of your bioreactor is 
required, collection and control be extended into each new cell or area 
of the bioreactor prior to initiating liquids addition in that area. 
Timely control of each area within the bioreactor is necessary to 
control the higher HAP emission rates in the first 2 to 5 years of 
bioreactor operation. As previously noted, a bioreactor cell can very 
quickly (within about 90 days of operation) reach the same gas 
generation rate as a conventional landfill cell does in 2 years of 
operation. A bioreactor shortens the time of waste degradation and 
stabilization and, thus, the period of most of the gas generation, from 
30 to 50 years for a conventional landfill to a period of 5 to 10 years 
for a bioreactor. Since significantly greater emissions occur in the 
first 5 years of bioreactor operation, controls should be extended into 
new bioreactor areas more quickly than in new areas of conventional 
landfills. This requirement is consistent with the way bioreactors are 
designed. Typically, horizontal gas collection systems are installed in 
the same area as the leachate recirculation system as the bioreactor is 
being filled. When the waste has been placed in the area and the 
leachate recirculation is started, the gas collection system will 
already be in place and can begin operation.
3. Why Are There Different Criteria for When Collection and Control 
Systems Can Be Removed From Bioreactors?
    We propose to allow more timely removal of controls from bioreactor 
operations because bioreactor emissions rates decline more rapidly 
after closure than conventional landfill emissions rates. The NSPS/EG 
and proposed landfills NESHAP allow capping or removal of the 
collection and control system from a conventional landfill after it 
meets three criteria: The landfill is permanently closed, measured 
uncontrolled emissions are less than 50 Mg/yr, and the control system 
has been in place for at least 15 years, as contained in 40 CFR 
60.752(b)(5). The NSPS/EG and proposed landfills NESHAP also allow for 
nonproductive areas of a landfill to be excluded from control if these 
areas contribute less than 1 percent of the total amount of NMOC 
emissions from the landfill, as described in 40 CFR 63.759(a)(3).
    We are proposing that you can choose to cap or remove controls from 
the bioreactor when either (1) the criteria in the NSPS/EG are met; or 
(2) the bioreactor is permanently closed (as defined in the NSPS/EG), 
liquids addition to the bioreactor has permanently ceased, and no 
liquids have been added to the bioreactor for at least 1 year. We are 
proposing this option because the 15-year control period may not be 
appropriate for bioreactors because bioreactor emissions are highest 
during the period of liquids addition, which generally stops when most 
biodegradation has occurred and the waste is stabilized. After this 
point, gas generation declines rapidly. As gas flows and HAP emissions 
rates decline, methane concentrations may also decline, thus requiring 
supplemental fuel to combust landfill gas. Waiting to remove controls 
until 1 year after liquids addition has ceased will ensure that the 
period of maximum emissions is controlled.
    Our analyses show that even allowing timely removal, the total mass 
of emissions controlled from a bioreactor will be greater than from a 
conventional landfill accepting the same amount of waste. Improved 
control of landfill gas emissions will occur because the requirement 
for timely installation of controls in bioreactors is concurrent with 
the period when bioreactor emissions are concentrated over a shorter 
period of time. The timing of this requirement results in a higher 
proportion of emissions being collected, which allows for better 
control of landfill gas emissions.
    If a bioreactor complies with the requirements for collection and 
control system removal in the proposed landfills NESHAP, it will also 
be considered in compliance with the NSPS or the Federal plan that 
implements the EG. This will avoid conflicting requirements where the 
proposed landfills NESHAP allow timely removal of control systems from 
bioreactors, whereas the NSPS or Federal plan requirements include the 
15-year criterion for all landfills and could appear to continue to 
require bioreactor control for a longer period of time than the 
proposed landfills NESHAP.
4. How Did EPA Determine When the Initial Semiannual Compliance Report 
for Bioreactors Must Be Submitted?
    The date for submittal of the initial semiannual compliance report 
including performance test results depends on the date that control 
system startup is required. For conventional landfills, the first 
report must be submitted within 180 days of installation and startup of 
the collection and control system per 40 CFR 60.757(f). For 
conventional landfills, the date of installation and startup are the 
same date. For bioreactors at new sources, and bioreactors that begin 
operating at existing sources after the 3-year compliance date, the 
proposed bioreactor provisions specify that the collection and control 
system must be installed by the date of liquids addition. However, the 
control system would not be required to start operation on the date of 
liquids addition. The control system must start operation within 90 
days after the date liquids addition begins. The first semiannual 
compliance report containing the performance test results is therefore 
due within 180 days of the required date for control system startup 
(i.e., 270 days after the initiation of liquids addition). This allows 
the same 180-day period from the date of control system startup that is 
allowed for other landfills. It also allows time for the source to gain 
familiarity with operating the new control device, schedule and conduct 
a performance test, receive the analytical results, and prepare a 
report. After the initial report, semiannual reports will be submitted 
every 6 months, the same as proposed for conventional landfills.
    For bioreactors at existing sources, the landfill has 3 years from 
the date the final rule is published to install and begin operating a 
gas collection and control system. For these bioreactors, the proposed 
date for control system installation and startup are the same date, so 
the initial compliance report including performance test results is due 
within 180 days of installation and startup of the collection and 
control system. This is the same as required for conventional landfills 
under 40 CFR 60.757(f).
    The date for submitting the initial semiannual compliance report 
for some bioreactors is different for conventional versus bioreactor 
landfills, however, an owner or operator may elect to streamline 
subsequent semiannual reporting. The EPA expects that a number of 
owners or operators may be required to submit semiannual reports for 
both the bioreactor and the conventional portion of their landfill.

[[Page 36467]]

To streamline reporting for such owners or operators, EPA is proposing 
to allow them to delay submitting the subsequent semiannual report for 
the bioreactor until the initial or subsequent semiannual report is due 
for the conventional portion of the landfill. The owner or operator 
cannot delay submittal of the subsequent semiannual report for the 
bioreactor by more than 12 months after submittal of the initial 
semiannual report. For example, if the initial compliance report for 
the bioreactor were submitted on December 30, 2002, then the subsequent 
semiannual report for the bioreactor would be due on June 30, 2003. 
Suppose the semiannual report for the conventional portion of the 
landfill is due on September 30, 2003 (but no later than December 30, 
2003). The owner or operator may delay submitting the semiannual report 
for the bioreactor from June 30 until September 30, when the report is 
due for the conventional portion of the landfill. Subsequent semiannual 
reporting for the bioreactor and the conventional portion of the 
landfill would be on the same schedule.
5. Why Are Moisture Content Records Needed and How Can Percent Moisture 
Be Determined?
    To be considered a bioreactor, a liquid other than leachate must be 
added, and the waste must have a minimum average moisture content of 40 
percent by weight. We expect that most landfills where liquid other 
than leachate is added will meet the definition of a bioreactor. If a 
landfill owner and/or operator complies with the bioreactor control 
requirements, they do not need to keep records of percent moisture 
content. If a landfill owner and/or operator adds liquid other than 
leachate but the portion of the landfill into which the liquid is added 
does not meet the 40 percent moisture criterion, they do not need to 
comply with the bioreactor control requirements. They must, however, 
keep a record of their percent moisture calculation to show that the 
landfill is not a bioreactor.
    The proposed landfills NESHAP allow landfills to use site-specific 
procedures to calculate moisture content, rather than prescribing one 
specific method. Because of differences in climate, rainfall, waste 
composition, bioreactor design, and other factors, a single calculation 
method would not be appropriate for all landfills. Furthermore, 
allowing site-specific approaches minimizes the recordkeeping burden by 
allowing landfills to use calculations they already have available, 
assuming the procedures and assumptions are documented and appropriate.
    A range of appropriate methods for calculation of landfill moisture 
content exists. For example, a simplified mass balance approach can be 
used. A landfill can track the amount of incoming waste, estimate the 
incoming moisture content of the waste, track the amount of liquids 
added, and the water removed as leachate. They would then calculate the 
in-situ moisture content based on the initial moisture content plus the 
liquids added minus the liquids removed. In some cases, a more complex 
mass balance that considers the addition of moisture from rain and snow 
and the loss of moisture from evaporation is used. For example, a more 
complex mass balance would be appropriate where rainfall is high and 
the landfill cover and drainage system is not designed to prevent rain 
from penetrating into the waste.
    Another estimation option for existing landfills that are already 
adding liquids includes measuring the moisture content of the waste in 
the landfill. However, given the heterogeneity of the waste, sampling 
in only one or a small number of locations may not provide a 
representative moisture level. For this reason, some sites may use a 
more intricate method of estimation, such as taking a large number of 
moisture content samples from throughout the landfill and analyzing 
them using a computer software package such as Geographical Information 
System. A statistical analysis of the results could provide an average 
percent moisture for the portion of the landfill to which liquid is 
added. However, it is expected that in most cases, a mass balance 
approach will be adequate to determine whether moisture content is 
below 40 percent, and comprehensive sampling will not be needed. For a 
landfill that has not yet started liquids addition, the sampling 
approach is not possible so a mass balance approach would be used.
6. Why Don't the Proposed Bioreactor Provisions Apply to Landfills That 
Are Closed?
    It is unlikely that bioreactors would be created in landfills that 
are already closed. If a bioreactor were built in such a landfill, the 
NSPS/EG should already require control of the entire landfill, 
including the bioreactor if the landfill is larger than 2.5 million Mg 
and 2.5 million m3, because landfills larger than the design 
capacity cutoff would reach 50 Mg/yr NMOC emissions before their 
closure date based on emissions calculation procedures in the NSPS/EG. 
Because these closed landfills will already have installed or be in the 
process of installing controls for the NSPS/EG, it is not necessary to 
require more timely control of bioreactors. In the less likely event 
that a closed landfill meeting the design capacity criteria never 
reached 50 Mg/yr uncontrolled NMOC emissions and never had to install 
controls, its emissions are already in decline so the bioreactor 
control provisions are not warranted.

F. What Other Issues Did EPA Consider?

    The proposed bioreactor requirements apply to only those areas 
within a landfill that are being operated as anaerobic (including 
hybrid) bioreactors. The landfill continues to be subject to the NSPS 
or the applicable State, Tribal, or Federal plan that implements the EG 
and would also be subject to the landfills NESHAP requirements proposed 
on November 7, 2000 when they become final. This means that landfills 
would continue to comply with the NSPS/EG by calculating their annual 
NMOC emissions rates and installing collection and control systems in 
the conventional portions of a landfill within 30 months of the first 
annual emissions rate report showing that uncontrolled emissions have 
reached the 50 Mg/yr NMOC emissions rate cutoff.
    To calculate annual emission rates for the NSPS/EG and the proposed 
landfills NESHAP and determine when to install control in the 
conventional portion of the landfill, the landfill should continue to 
include the entire mass of waste accepted in the landfill (including 
the bioreactor and the conventional areas of the landfill) when using 
the NSPS/EG emissions equations. This is the procedure currently 
required under the NSPS/EG, and it is not our intent to change the 
NSPS/EG requirements or to change the timing of when the conventional 
portions of a landfill would require control.
    We considered two other options. The first option would be to 
require a landfill that includes both bioreactor and conventional areas 
to use a higher k value for the bioreactor or to measure uncontrolled 
emissions from the bioreactor and add them to emissions from the 
conventional portion of the landfill when calculating NSPS/EG control 
applicability. This would cause the landfill as a whole to reach 50 Mg/
yr uncontrolled emissions sooner than calculated by the NSPS/EG 
procedures. It would, therefore, have the effect of requiring the 
conventional portion of the landfill to control emissions before the 
NSPS/EG would require control, thus penalizing landfills that use 
bioreactors in combination with

[[Page 36468]]

conventional areas. Therefore, this option was rejected. By requiring 
the bioreactor at such a landfill to install controls at the start of 
liquids addition and by not changing the emissions calculation 
procedure in the NSPS/EG, the proposed procedures address the problem 
of the increased landfill gas generation rate from the bioreactor 
without affecting when the conventional portion of the landfill is 
required to install controls.
    The second option was to exclude the bioreactor from the annual 
NMOC emissions rate calculations required by the NSPS/EG. This would 
have the effect of changing the number of landfills that require 
control and the emissions reduction expected under the NSPS/EG. For 
example, a large landfill where half the area was operated as a 
bioreactor and half as a conventional landfill could escape control 
because emissions estimates from the amount of waste placed in just the 
conventional portion might not reach 50 Mg/yr NMOC, whereas emission 
estimates from the landfill as a whole would be well above 50 Mg/yr 
NMOC. The NSPS/EG envisioned controlling such landfills, and their 
control has been shown to be reasonable and cost effective. Therefore, 
the proposed landfills NESHAP provisions for bioreactors do not change 
the calculation procedures in the NSPS/EG and will have no effect on 
which landfills require control by the NSPS/EG, or the date that 
controls must be installed in the conventional portions of a landfill.
    Aerobic bioreactors are a relatively new concept, and EPA knows of 
no full scale aerobic bioreactors in operation in the United States. A 
limited amount of information is available. In aerobic bioreactors, air 
and liquids promote aerobic decomposition of waste. The waste 
decomposes rapidly due to the presence of oxygen and moisture. The 
aerobic decomposition produces large amounts of gases including carbon 
dioxide. Compared to conventional landfills, the increased temperature 
and increased air flow through the waste may result in increased 
emissions rates of organic compounds (including organic HAP) soon after 
the aerobic bioreactor begins operation. However, aerobic landfill data 
are insufficient to characterize HAP emissions from this type of 
operation. In addition, the gas composition from a landfill operated 
only as aerobic bioreactor is expected to have higher levels of carbon 
dioxide, nitrogen, and oxygen, and significantly lower levels of 
methane. This may result in the gas being more difficult to safely 
combust, unless it is combined with a large flow of higher-methane gas 
from anaerobic areas of the landfill or with other fuels.
    The EPA is not expecting a significant number of aerobic 
bioreactors to be built in the next several years (in contrast to the 
trend for anaerobic bioreactors). Concerns over the increased potential 
for landfill fires and added power costs have deterred use of aerobic 
bioreactor technology. Some pilot projects have created odor concerns 
and in some cases are no longer being operated. Given the fact that EPA 
knows of no full scale aerobic bioreactors in operation in the United 
States and that very few pilot projects are in operation or expected to 
startup in the near future, EPA has concluded that it is not necessary 
for the supplemental proposal to address aerobic bioreactors.
    Portions of a landfill that are operated as aerobic bioreactors 
would continue to be subject to the NSPS/EG and the proposed landfills 
NESHAP requirements. If a landfill that includes an aerobic bioreactor 
meets the design capacity and uncontrolled NMOC emissions rate criteria 
in the NSPS/EG, a collection and control system must be installed in 
the landfill, including the aerobic bioreactor area, according to the 
schedule in the NSPS/EG. Landfills with pilot scale aerobic bioreactors 
have had some success in routing emissions from the aerobic bioreactor 
with other landfill area emissions for control in flares.
    Section 112(f) of the CAA requires EPA to evaluate residual risks 
and promulgate standards to address residual risks within 8 years of 
promulgation of the NESHAP. At that time, we will consider any new 
information on the prevalence and emissions of aerobic bioreactors and 
determine if any additional requirements are appropriate.

V. Summary of Environmental, Energy, and Economic Impacts of the 
Proposed Requirements for Bioreactors

    We expect a positive environmental impact and negligible economic 
impacts from the requirements of the supplemental proposal. One reason 
for the small economic impact is that the supplemental proposal would 
require gas collection and control for only the same landfills that are 
already required to install collection and control systems under the 
NSPS/EG and the proposed landfills NESHAP. It will not change the 
number of landfills that must apply controls.
    In the previous analyses for the NSPS/EG and proposed landfills 
NESHAP, it was assumed that all landfills are conventional landfills 
and install and remove control systems according to the schedule in the 
NSPS/EG. To see if the supplemental proposal would increase emissions 
reductions, environmental, cost and economic impacts relative to those 
previously calculated, we compared the emissions reductions and costs 
for timely control of a bioreactor according to the schedule proposed 
in the supplemental proposal with the emissions reductions and costs 
for controlling a conventional landfill that accepts the same amount of 
waste and installs controls according to the NSPS/EG schedule. We found 
that greater emissions reductions are achieved by timely control of the 
bioreactor landfill. A bioreactor landfill with a design capacity of 
2.5 million Mg achieves an emissions reduction of 1,770 Mg of HAP over 
the period of control, compared to 1,630 Mg of HAP reduction for a 
conventional landfill receiving the same amount of waste. The 
bioreactor is controlled for 13 years less than the conventional 
landfill, yet achieves greater emissions reductions. Similarly, a 
bioreactor landfill with a design capacity of 10 million Mg achieves 
emissions reductions of 7,300 Mg of HAP, compared to 7,040 Mg of HAP 
reductions for a conventional landfill receiving the same amount of 
waste. The bioreactor is controlled for 30 years less than the 
conventional landfill, yet achieves greater emissions reductions. This 
analysis leads to the conclusion that implementation of the 
supplemental proposal would achieve additional HAP emissions 
reductions, which will minimize any health impacts from exposure to HAP 
in landfill gas emissions and lead to other environmental benefits 
associated with reduction of other landfill gas constituents including 
NMOC, which contribute to photochemical formation of smog, and methane, 
a potent greenhouse gas. Odor problems will also be minimized.
    The energy impacts of the supplemental proposal would be positive. 
Many bioreactors are expected to comply with the proposed rules by 
recovering landfill gas to generate energy. Our analysis shows that a 
bioreactor with a design capacity of 2.5 million Mg can generate a 
greater profit than a similar conventional landfill from sale of 
landfill gas for direct use (such as combustion in nearby boilers to 
provide steam to an industrial process or to heat a building). 
Similarly, using a combustion control device, such as an internal 
combustion engine, that generates electricity from the landfill gas is 
profitable for a 10 million Mg bioreactor, where it may not be

[[Page 36469]]

profitable for a similar size conventional landfill. The number of 
landfill gas direct use and electricity generation projects has grown 
in recent years, and industry commenters stated in the public comments 
that bioreactors provide an opportunity for economically feasible use 
of landfill gas to generate energy. To the extent that these energy 
recovery options are used instead of flares to comply with the 
supplemental proposal, this will result in the generation of additional 
electricity, offset the use of fossil fuels, and have a beneficial 
energy impact.
    To determine if the cost of the supplemental proposal would 
increase the control costs previously predicted for the NSPS/EG and 
proposed landfills NESHAP, we analyzed the cost of control for 
bioreactors installing controls according to the schedule in the 
supplemental proposal compared to the costs for control of conventional 
landfills according to the schedule in the NSPS/EG. We examined costs 
for flares and energy generation options. The costs included capital, 
operating, and maintenance costs. For energy recovery options, revenues 
from the sale of landfill gas or electricity were included. Costs were 
expressed on a NPV basis because the costs of the landfill gas 
collection and control systems are highly variable over the life of the 
landfill. In addition, the timing of control system installation and 
the length of the control period will vary greatly based on landfill 
size, design, landfill gas flow rates, and gas composition. For 
fluctuating costs over a variable but long life of the landfill control 
system, this cost analysis compares the costs between various landfills 
and control options based on a NPV analysis. The NPV analysis removes 
the effects of the varying costs and lifetimes by converting them into 
a single present cost that is equal to the string of costs that the 
landfill would experience over its full lifetime.
    For the flare control options, the NPV costs to control the 
bioreactor were slightly greater than the costs to control a 
conventional landfill. This is because the bioreactor would have to 
install control sooner, and the NPV calculation weighs earlier 
expenditures more heavily to account for the time value of money. 
However, the bioreactor NPV control cost is only about 10 percent 
greater than the conventional landfill control cost for all but one of 
the smaller landfill cases examined. For example, a bioreactor landfill 
with a design capacity of 2.5 million Mg, the NPV costs for a gas 
collection and flare system were estimated to be $1.5 million, compared 
to $1.3 million for a conventional landfill with the same design 
capacity. Furthermore, bioreactors experience cost savings compared to 
conventional landfills due to factors such as the reduced amount of 
land space needed to hold the same mass of waste, and reduced leachate 
treatment, transportation, and disposal costs. When such differences 
are considered, it is significantly less costly to build a bioreactor, 
even with the more timely control requirements, than to build a 
conventional landfill. This was true for all cases examined.
    The examination of energy recovery NPV costs showed that the 
bioreactors are less costly, or more profitable, to control than 
conventional landfills in all of the cases examined. In many cases, 
timely control of a bioreactor using an energy generation option will 
result in a net profit rather than a net cost. For a bioreactor 
landfill with a design capacity of 10 million Mg that controls 
emissions by using an internal combustion engine that generates 
electricity for sale to the power grid, the revenues from the sale of 
electricity balance the costs of the gas collection and control system 
resulting in an estimated NPV cost savings (or net revenue) of 
approximately $0.1 million. A conventional landfill with the same 
design capacity is estimated to incur an NPV cost of approximately $5 
million. Smaller bioreactors that can control emissions by collecting 
landfill gas and delivering it to a nearby industry, commercial 
establishment, or institution for direct use in a boiler, process 
heater, or other energy recovery system can also realize a greater net 
revenue than similar size conventional landfills.
    Given these results, we conclude that the supplemental proposal 
would not increase the costs of control for most landfills compared to 
the previous cost analyses, and some landfills with bioreactors will 
experience reduced control costs. We expect the number of bioreactors 
to increase over the next few years given their potential environmental 
and economic benefits and pending regulatory clarifications. Overall, 
the supplemental proposal would have minimal economic impacts and may 
in fact have an overall beneficial economic impact. Additional 
information on this analysis, including additional cases examined, HAP 
emissions reductions, and NMOC emissions reductions are contained in 
Docket No. A-98-28.

VI. Administrative Requirements

A. Executive Order 12866, Regulatory Planning and Review

    Under Executive Order 12866 (58 FR 51735, October 4, 1993), EPA 
must determine whether the regulatory action is ''significant,'' and 
therefore, subject to review by the Office of Management and Budget 
(OMB) and the requirements of the Executive Order. The Executive 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.
    Pursuant to the terms of Executive Order 12866, it has been 
determined that the supplemental proposal is not a ''significant 
regulatory action'' because it will not have an annual effect on the 
economy of $100 million or more.

B. Executive Order 13132, Federalism

    Executive Order 13132, entitled ''Federalism'' (64 FR 43255, August 
10, 1999), requires EPA to develop an accountable process to ensure 
''meaningful and timely input by State and local officials in the 
development of regulatory policies that have federalism implications.'' 
''Policies that have federalism implications'' are defined in the 
Executive Order to include regulations that have ''substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government.''
    Under Executive Order 13132, EPA may not issue a regulation that 
has federalism implications, that imposes substantial direct compliance 
costs, and that is not required by statute, unless the Federal 
government provides the funds necessary to pay the direct compliance 
costs incurred by State and local governments, or EPA consults with 
State and local officials early in the process of developing the 
proposed regulation. The EPA also may not issue

[[Page 36470]]

a regulation that has federalism implications and that preempts State 
law unless EPA consults with State and local officials early in the 
process of developing the proposed regulation.
    The supplemental proposal for MSW landfills will not have 
substantial direct effects on the States, on the relationship between 
the national government and the States, or on the distribution of power 
and responsibilities among the various levels of government, as 
specified in Executive Order 13132. The EPA has concluded that the 
supplemental proposal may create a mandate on a number of city and 
county governments, and the Federal government would not provide the 
funds necessary to pay the direct costs incurred by these city and 
county governments in complying with the mandate. However, the 
supplemental proposal does not impose any additional control costs or 
result in any additional control requirements above those considered 
during promulgation of the 1996 EG/NSPS. In developing the 1996 EG/
NSPS, EPA consulted extensively with State and local governments to 
enable them to provide meaningful and timely input in the development 
of that rulemaking. Because the control requirements of the 
supplemental proposal are substantially the same as those developed in 
1996, these previous consultations still apply. For a discussion of 
EPA's consultations with State and local governments, the nature of the 
governments' concerns, and EPA's position supporting the need for the 
specific control requirements included in both the EG/NSPS and the 
supplemental proposal, see the preamble to the 1996 EG/NSPS (60 FR 
9918, March 12, 1996). Thus, the requirements of section 6 of the 
Executive Order do not apply to the supplemental proposal.

C. Executive Order 13175, Consultation and Coordination With Indian 
Tribal Governments

    Executive Order 13175, entitled ''Consultation and Coordination 
with Indian Tribal Governments'' (65 FR 67249, November 6, 2000) took 
effect on January 6, 2001, after publication of the proposed landfills 
NESHAP. Executive Order 13175 requires EPA to develop an accountable 
process to ensure meaningful and timely input by tribal officials in 
the development of regulatory policies that have tribal implications. 
''Policies that have tribal implications'' is defined in the Executive 
Order to include regulations that have ''substantial direct effects on 
one or more Indian tribes, on the relationship between the Federal 
government and Indian Tribes, or on the distribution of power and 
responsibilities between the Federal government and Indian Tribes.''
    The supplemental proposal does not have tribal implications. It 
will not have substantial direct effects on tribal governments, on the 
relationship between the Federal government and Indian tribes, or on 
the distribution of power and responsibilities between the Federal 
government and Indian tribes as specified in Executive Order 13175. 
Thus, the requirements of Executive Order 13175 do not apply to the 
supplemental proposal.
    In the spirit of Executive Order 13175, and consistent with EPA 
policy to promote communications between EPA and tribal governments, 
EPA specifically solicits additional comment on the supplemental 
proposal from tribal officials.

D. Executive Order 13045, Protection of Children From Environmental 
Health Risks and Safety Risks

    Executive Order 13045 (62 FR 19885, April 23, 1997) applies to any 
rule that: (1) Is determined to be ''economically significant'' as 
defined under Executive Order 12866, and (2) concerns an environmental 
health or safety risk that EPA has reason to believe may have a 
disproportionate effect on children. If the regulatory action meets 
both criteria, EPA must evaluate the environmental health or safety 
effects of the planned rule on children and explain why the planned 
rule is preferable to other potentially effective and reasonably 
feasible alternatives considered by EPA.
    The EPA interprets Executive Order 13045 as applying only to those 
regulatory actions that are based on health or safety risks, such that 
the analysis required under section 5-501 of the Executive Order has 
the potential to influence the regulation.
    The supplemental proposal is not subject to Executive Order 13045 
because it is based on technology performance and not on health or 
safety risks. No children's risk analysis was performed because no 
alternative technologies exist that would provide greater stringency at 
a reasonable cost. Furthermore, the supplemental proposal has been 
determined to be not ''economically significant'' as defined under 
Executive Order 12866.

E. Executive Order 13211, Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use

    The supplemental proposal is not subject to Executive Order 13211, 
''Actions Concerning Regulations That Significantly Affect Energy 
Supply, Distribution, or Use'' (66 FR 28355, May 22, 2001) because it 
is not a significant regulatory action under Executive Order 12866.

F. Unfunded Mandates Reform Act of 1995

    Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public 
Law 104-4, establishes requirements for Federal agencies to assess the 
effects of their regulatory actions on State, local, and tribal 
governments and the private sector. Under section 202 of the UMRA, the 
EPA generally must prepare a written statement, including a cost-
benefit analysis, for proposed and final rules with ''Federal 
mandates'' that may result in expenditures by State, local, and tribal 
governments, in aggregate, or by the private sector, of $100 million or 
more in any 1 year. Before promulgating an EPA rule for which a written 
statement is needed, section 205 of the UMRA generally requires the EPA 
to identify and consider a reasonable number of regulatory alternatives 
and adopt the least-costly, most cost effective, or least burdensome 
alternative that achieves the objectives of the rule. The provisions of 
section 205 do not apply when they are inconsistent with applicable 
law. Moreover, section 205 allows the EPA to adopt an alternative other 
than the least costly, most cost effective, or least burdensome 
alternative if the Administrator publishes with the final rule an 
explanation why that alternative was not adopted. Before the EPA 
establishes any regulatory requirements that may significantly or 
uniquely affect small governments, including tribal governments, it 
must have developed under section 203 of the UMRA a small government 
agency plan. The plan must provide for notifying potentially affected 
small governments, enabling officials of affected small governments to 
have meaningful and timely input in the development of EPA regulatory 
proposals with significant Federal intergovernmental mandates, and 
informing, educating, and advising small governments on compliance with 
the regulatory requirements.
    The EPA has determined that the supplemental proposal does not 
contain a Federal mandate that may result in expenditures of $100 
million or more for State, local, and tribal governments, in the 
aggregate, or the private sector in any 1 year. The EPA expects the 
requirements in the supplemental proposal to have a negligible economic 
impact. Thus, the supplemental proposal is not subject to the 
requirements of section 202 and 205 of

[[Page 36471]]

the UMRA. In addition, the EPA has determined that the supplemental 
proposal contains no regulatory requirements that might significantly 
or uniquely affect small governments because the burden is small and 
the supplemental proposal does not unfairly apply to small governments. 
Therefore, the supplemental proposal is not subject to the requirements 
of section 203 of the UMRA.

G. Regulatory Flexibility Act (RFA) As Amended By the Small Business 
Regulatory Enforcement Fairness Act of 1996 (SBREFA), 5 U.S.C. 601 et 
seq.

    The RFA generally requires an agency to prepare a regulatory 
flexibility analysis of any rule subject to notice and comment 
rulemaking requirements under the Administrative Procedures Act or any 
other statute unless the agency certifies that the rule will not have a 
significant impact on a substantial number of small entities. Small 
entities include small businesses, small organizations, and small 
governmental jurisdictions.
    For purposes of assessing the impacts of today's supplemental 
proposal on small entities, small entity is defined as: (1) A small 
business that is primarily engaged in the collection and disposal of 
refuse in a landfill operation as defined by NAICS codes 562212 and 
924110 with annual receipts less than 10 million dollars; (2) a small 
governmental jurisdiction that is a government of a city, county, town, 
school district, or special district with a population of less than 
50,000; and (3) a small organization that is any not-for-profit 
enterprise which is independently owned and operated and is not 
dominant in its field.
    After considering the economic impacts of today's supplemental 
proposal for MSW landfills on small entities, I certify that this 
action will not have a significant economic impact on a substantial 
number of small entities (SISNOSE). The supplemental proposal will not 
impose any requirements on small entities. In gathering available data 
on the owners of the ten bioreactor projects that are the population of 
sources used to identify the MACT floor for the supplemental proposal, 
we found that none of the ten projects were owned by small entities 
that met the SBA definition. Given that the landfill capacity of no 
other bioreactor project from the available data was identified to be 
larger than the landfill capacity exemptions, these data provide 
evidence to support the determination that there is no SISNOSE 
associated with this action.
    Although no small entities were identified, the supplemental 
proposal would impose minimal economic impact on small entities because 
controls for bioreactor operations would be applied sooner than under 
the NSPS/EG. In addition, there may be cost savings for most of the 
sources that install bioreactors as compared to using conventional 
landfill operations. Also, the design capacity exemptions of 2.5 
million Mg and 2.5 million m\3\ excludes smaller landfills that can 
least afford the costs of collection and control systems, which will 
include many landfills owned by small businesses and small 
municipalities.
    We continue to be interested in the potential impacts of the 
supplemental proposal on small entities and welcome comments on issues 
related to such impacts. For more information on potential impacts to 
small entities, please consult the economic impact analysis for the 
proposed landfills NESHAP in the public docket.

H. Paperwork Reduction Act

    An Information Collection Request (ICR) document has been prepared 
for the November 7, 2000 proposed landfills NESHAP by EPA (ICR No. 
1938.01) and submitted to OMB for approval under the Paperwork 
Reduction Act, 44 U.S.C. 3501 et seq. A copy may be obtained from Sandy 
Farmer by mail at the Office of Environmental Information, Collection 
Strategies Division, U.S. EPA (2822), 1200 Pennsylvania Avenue, NW, 
Washington, DC 20460, by e-mail at [email protected], or by calling 
(202) 260-2740. A copy may also be downloaded off the Internet at 
http://www.epa.gov/icr.
    Burden means total time, effort, or financial resources expended by 
persons to generate, maintain, retain, or disclose or provide 
information to or for a Federal agency. This includes the time needed 
to review instructions; develop, acquire, install, and utilize 
technology and systems for the purposes of collecting, validating, and 
verifying information, processing and maintaining information, and 
disclosing and providing information; adjust the existing ways to 
comply with any previously applicable instructions and requirements; 
train personnel to be able to respond to a collection of information; 
search data sources; complete and review the collection of information; 
and transmit or otherwise disclose the information.
    An Agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for the 
EPA's regulations are listed in 40 CFR part 9 and 48 CFR chapter 15.

I. National Technology Transfer and Advancement Act

    Under section 12(d) of the National Technology Transfer and 
Advancement Act of 1995 (NTTAA), Public Law 104-113, all Federal 
agencies are required to use voluntary consensus standards (VCS) in 
their regulatory and procurement activities unless to do so would be 
inconsistent with applicable law or otherwise impractical. Voluntary 
consensus standards are technical standards (e.g., materials 
specifications, test methods, sampling procedures, business practices) 
developed or adopted by one or more voluntary consensus bodies. The 
NTTAA requires Federal agencies to provide Congress, through annual 
reports to the OMB, with explanations when an agency does not use 
available and applicable VCS.
    The supplemental proposal uses the same technical standards as the 
proposed rule and does not introduce new standards. Therefore, the 
requirements of the NTTAA do not apply to the supplemental proposal.

List of Subjects in 40 CFR Part 63

    Environmental protection, Air pollution control, Hazardous 
substances, Reporting and recordkeeping requirements.

    Dated: May 16, 2002.
Christine Todd Whitman,
Administrator.

    For the reasons stated in the preamble, title 40, chapter I, part 
63 of the Code of Federal Regulations is proposed to be amended as 
follows:

PART 63-[AMENDED]

    1. The authority citation for part 63 continues to read as follows:

    Authority: 42 U.S.C. 7401 et seq.

Subpart AAAA-National Emission Standards for Hazardous Air 
Pollutants: Municipal Solid Waste Landfills

    2. Section 63.1935, as proposed at 65 FR 66683 on November 7, 2000, 
is amended by designating the existing paragraph in this section as 
paragraph (a) and adding new paragraph (b) to read as follows:


 63.1935  Am I subject to this subpart?

* * * * *
    (b) If you own or operate a major or area source MSW landfill with 
a design capacity greater than or equal to 2.5

[[Page 36472]]

million Mg and 2.5 million m3 that includes a bioreactor, as 
defined in  63.1990, then you are subject to this subpart.
    3. Subpart AAAA, as proposed at 65 FR 66684 on November 7, 2000, is 
amended by adding  63.1947 to read as follows:


 63.1947  When do I have to comply with this subpart if I own 
or operate a bioreactor?

    If you own or operate a bioreactor located at a landfill that is 
not permanently closed as of the date of publication of the final rule 
in the Federal Register and has a design capacity equal to or greater 
than 2.5 million Mg and 2.5 million m3, then you must 
install and operate a collection and control system that meets the 
criteria in 40 CFR 60.752(b)(2), subpart WWW; the Federal plan; or EPA-
approved and effective State plan according to the schedule specified 
in paragraph (a) or (b) of this section.
    (a) If your bioreactor is at a new affected source, then you must 
meet the requirements in paragraphs (a)(1) and (2) of this section:
    (1) Install the gas collection and control system for the 
bioreactor before initiating liquids addition.
    (2) Begin operating the gas collection and control system within 90 
days after initiating liquids addition.
    (b) If your bioreactor is at an existing affected source and your 
bioreactor is not already required to install a gas collection and 
control system under 40 CFR part 60, subpart WWW; the Federal plan; or 
EPA-approved and effective State plan, then you must install and begin 
operating the gas collection and control system for the bioreactor 
within 3 years after the date of publication of the final rule in the 
Federal Register.
    (c) If your bioreactor is at an existing affected source and you do 
not initiate liquids addition to your bioreactor until later than 3 
years after the date of publication of the final rule in the Federal 
Register, then you must meet the requirements in paragraphs (c)(1) and 
(2) of this section:
    (1) Install the gas collection and control system for the 
bioreactor before initiating liquids addition.
    (2) Begin operating the gas collection and control system within 90 
days after initiating liquids addition.
    4. Subpart AAAA, as proposed at 65 FR 66684 on November 7, 2000, is 
amended by adding  63.1952 to read as follows:


 63.1952  When am I no longer required to comply with the 
requirements of this subpart if I own or operate a bioreactor?

    If you own or operate a bioreactor, you are no longer required to 
comply with the requirements of this subpart provided you meet the 
conditions of either paragraph (a) or (b) of this section.
    (a) Your affected source meets the control system removal criteria 
in 40 CFR 60.752(b)(v), subpart WWW, or the bioreactor meets the 
criteria for a nonproductive area of the landfill in 40 CFR 
60.759(a)(3)(ii), subpart WWW.
    (b) The bioreactor portion of the landfill is a closed landfill as 
defined in 40 CFR 60.751, subpart WWW, you have permanently ceased 
adding liquids to the bioreactor, and you have not added liquids to the 
bioreactor for at least 1 year. A closure report for the bioreactor 
must be submitted to the Administrator as provided in 40 CFR 60.757(d), 
subpart WWW.
    (c) Compliance with the bioreactor control removal provisions in 
this section constitute compliance with 40 CFR part 60, subpart WWW, or 
the Federal plan, whichever applies to your bioreactor.
    5. Section 63.1955, as proposed at 65 FR 66684 on November 7, 2000, 
is amended by adding paragraph (c) to read as follows:


 63.1955  What requirements must I meet?

* * * * *
    (c) If you own or operate a bioreactor that is located at an MSW 
landfill that is not permanently closed and has a design capacity equal 
to or greater than 2.5 million Mg and 2.5 million m3, then 
you must meet the requirements of paragraph (a) and the additional 
requirements in paragraphs (c)(i) and (ii) of this section.
    (i) You must comply with the general provisions specified in Table 
1 of this subpart and in  63.1960 through  63.1985 
starting on the date you are required to install the gas collection and 
control system.
    (ii) You must extend the collection and control system into each 
new cell or area of the bioreactor prior to initiating liquids addition 
in that area instead of the schedule in 40 CFR 60.752(b)(2)(ii)(A)(2).
    6. Section 63.1980, as proposed at 65 FR 66684 on November 7, 2000, 
is amended by adding new paragraphs (c) through (g) to read as follows:


 63.1980  What records and reports must I keep and submit?

* * * * *
    (c) For bioreactors at new affected sources, you must submit the 
initial semiannual compliance report and performance test results 
described in 40 CFR 60.757(f), subpart WWW, within 180 days after the 
date you are required to begin operating the gas collection and control 
system by  63.1947(a)(2).
    (d) For bioreactors at existing affected sources, you must submit 
the initial semiannual compliance report and performance test results 
described in 40 CFR 60.757(f), subpart WWW, within 180 days after the 
compliance date specified in  63.1947(b), unless you have 
previously submitted a compliance report for the bioreactor required by 
40 CFR part 60, subpart WWW; the Federal plan; or an EPA-approved and 
effective State plan.
    (e) For bioreactors that are located at existing affected sources 
but do not initiate liquids addition until later than the compliance 
date in  63.1947(b), you must submit the initial semiannual 
compliance report and performance tests results described in 40 CFR 
60.757(f), subpart WWW, within 180 days after the date you are required 
to begin operating the gas collection and control system by  
63.1947(c) of this subpart.
    (f) If you must submit a semiannual compliance report for a 
bioreactor as well as a semiannual compliance report for a conventional 
portion of the same landfill, you may delay submittal of a subsequent 
semiannual compliance report for the bioreactor according to paragraphs 
(f)(1) through (3) of this section so that the reports may be submitted 
on the same schedule.
    (1) After submittal of your initial semiannual compliance report 
and performance test results for the bioreactor, you may delay 
submittal of the subsequent semiannual compliance report for the 
bioreactor until the date the initial or subsequent semiannual 
compliance report is due for the conventional portion of your landfill.
    (2) You may delay submittal of your subsequent semiannual 
compliance report by no more than 12 months after the due date for 
submitting the initial semiannual compliance report and performance 
test results described in 40 CFR 60.757(f), subpart WWW, for the 
bioreactor. The report shall cover the time period since the previous 
semiannual report for the bioreactor, which would be a period of at 
least 6 months and no more than 12 months.
    (3) After the delayed semiannual report, all subsequent semiannual 
reports for the bioreactor must be submitted every 6 months on the same 
date the semiannual report for the conventional portion of the landfill 
is due.

[[Page 36473]]

    (g) If you add any liquids other than leachate in a controlled 
fashion to the waste mass, and you do not comply with the bioreactor 
requirements in  63.1947, 63.1955(c) and 63.1980(c) 
through (f), you must keep a record of calculations showing that the 
percent moisture by weight expected in the waste mass to which liquid 
is added is less than 40 percent. The calculation must consider the 
waste mass, moisture content of the incoming waste, mass of water added 
to the waste including leachate recirculation and other liquids 
addition, and the mass of water removed through leachate or other water 
losses. Moisture level sampling or mass balances calculations can be 
used. You must document the calculations and the basis of any 
assumptions.
    7. Section 63.1990, as proposed at 65 FR 66685 on November 7, 2000, 
is amended by adding in alphabetical order the definition of 
''bioreactor'' as follows:


 63.1990  What definitions apply to this subpart?

* * * * *
    Bioreactor means a municipal solid waste landfill or portion of a 
municipal solid waste landfill where any liquid other than leachate is 
added in a controlled fashion into the waste mass (often in combination 
with recirculating leachate) to reach a minimum average moisture 
content of 40 percent by weight or greater.
* * * * *
[FR Doc. 02-12845 Filed 5-22-02; 8:45 am]
BILLING CODE 6560-50-P