Standards of Performance for Municipal Solid Waste Landfills

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 60

[EPA-HQ-OAR-2003-0215; FRL-9912-12-OAR]

RIN 2060-AM08

Standards of Performance for Municipal Solid Waste Landfills

AGENCY:

Environmental Protection Agency.

ACTION:

Proposed rule.

SUMMARY:

The Environmental Protection Agency (EPA) is proposing a new subpart, 40 CFR part 60, subpart XXX that updates the Standards of Performance for Municipal Solid Waste Landfills. Under section 111 of the Clean Air Act, the EPA must review, and, if appropriate, revise standards of performance at least every 8 years. The EPA's review of the standards for municipal solid waste landfills applies to landfills that commence construction, reconstruction, or modification after July 17, 2014. The proposed standards reflect changes to the population of landfills and an analysis of the timing and methods for reducing emissions. The proposed standards also address other regulatory issues including the definition of landfill gas treatment systems, among other topics. The new subpart will reduce emissions of landfill gas, which contains both nonmethane organic compounds and methane. These avoided emissions will improve air quality and reduce public health and welfare effects associated with exposure to landfill gas emissions.

DATES:

Comments.

Comments must be received on or before September 15, 2014.

Public Hearing.

If anyone contacts the EPA requesting a public hearing by July 22, 2014, we will hold a public hearing on August 12, 2014, in Washington, DC at the William Jefferson Clinton East Building, Room 1153, 1201 Constitution Avenue NW., Washington, DC 20004. The public hearing will convene at 9:00 a.m. and end at 6:00 p.m. (Eastern Standard Time). There will be a lunch break from 12:00 p.m. to 1:00 p.m. Please contact Ms. Virginia Hunt at (919) 541-0832 or at

hunt.virginia@epa.gov

to register to speak at one of the hearings. The last day to pre-register in advance to speak at the hearings will be Friday August 8, 2014. Additionally, requests to speak will be taken the day of the hearing at the hearing registration desk, although preferences on speaking times may not be able to be fulfilled. If you require the service of a translator or special accommodations such as audio description, please let us know at the time of registration.

If no one contacts the EPA requesting a public hearing to be held concerning this proposed rule by July 22, 2014, a public hearing will not take place. If a hearing is held, it will provide interested parties the opportunity to present data, views or arguments concerning the proposed action. The EPA will make every effort to accommodate all speakers who arrive and register. Because this hearing, if held, will be at U.S. government facilities, individuals planning to attend the hearing should be prepared to show valid picture identification to the security staff in order to gain access to the meeting room. In addition, you will need to obtain a property pass for any personal belongings you bring with you. Upon leaving the building, you will be required to return this property pass to the security desk. No large signs will be allowed in the building, cameras may only be used outside of the building and demonstrations will not be allowed on federal property for security reasons.

The EPA may ask clarifying questions during the oral presentations, but will not respond to the presentations at that time. Written statements and supporting information submitted during the comment period will be considered with the same weight as oral comments and supporting information presented at the public hearing. Commenters should notify Ms. Hunt if they will need specific equipment, or if there are other special needs related to providing comments at the hearings. Verbatim transcripts of the hearing and written statements will be included in the docket for the rulemaking. The EPA will make every effort to follow the schedule as closely as possible on the day of the hearing; however, please plan for the hearing to run either ahead of schedule or behind schedule. Information regarding the hearing (including information as to whether or not one will be held) will be available at:

http://www.epa.gov/ttnatw01/landfill/landflpg.html.

ADDRESSES:

Submit your comments, identified by Docket ID Number EPA-HQ-OAR-2003-0215, by one of the following methods:

•

Federal eRulemaking Portal: http://www.regulations.gov.

Follow the online instructions for submitting comments.

•

Email:

A-and-R-docket@epa.gov.

Include docket ID No. EPA-HQ-OAR-2003-0215 in the subject line of the message.

•

Fax:

(202) 566-9744. Attention Docket ID No. EPA-HQ-OAR-2003-0215.

•

Mail:

Environmental Protection Agency, EPA Docket Center (EPA/DC), Mailcode 28221T, Attention Docket ID No. EPA-HQ-OAR-2003-0215, 1200 Pennsylvania Avenue NW., Washington, DC 20460. Please include a total of two copies. In addition, please mail a copy of your comments on the information collection provisions to the Office of Information and Regulatory Affairs, Office of Management and Budget, Attn: Desk Officer for EPA, 725 17th Street NW., Washington, DC 20503.

•

Hand/Courier Delivery:

EPA Docket Center, Room 3334, EPA WJC West Building, 1301 Constitution Avenue NW., Washington, DC 20004. Such deliveries are only accepted during the Docket's normal hours of operation, and special arrangements should be made for deliveries of boxed information.

Instructions:

Direct your comments to Docket ID No. EPA-HQ-OAR-2003-0215. The EPA's policy is that all comments received will be included in the public docket without change and may be made available online at

http://www.regulations.gov,

including any personal information provided, unless the comment includes information claimed to be confidential business information (CBI) or other information whose disclosure is restricted by statute.

Do not submit information that you consider to be CBI or otherwise protected through

http://www.regulations.gov

or email. Send or deliver information identified as CBI to only the mail or hand/courier delivery address listed above, attention: Mr. Roberto Morales, OAQPS Document Control Officer (Room C404-02), Office of Air Quality Planning and Standards, U.S. EPA, Research Triangle Park, NC 27711, Attention Docket ID No. EPA-HQ-OAR-2003-0215. The

http://www.regulations.gov

Web site is an “anonymous access” system, which means the EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an email comment directly to the EPA without going through

http://www.regulations.gov,

your email address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the Internet. If you submit an electronic comment, the EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD-ROM you submit. If the EPA cannot read your comment due to technical difficulties and cannot contact

you for clarification, the EPA may not be able to consider your comment. Electronic files should avoid the use of special characters, any form of encryption, and be free of any defects or viruses.

Docket:

All documents in the docket are listed in the

http://www.regulations.gov

index. Although listed in the index, some information is not publicly available, e.g., CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, will be publicly available only in hard copy. Publicly available docket materials are available either electronically in

http://www.regulations.gov

or in hard copy at the Air Docket, EPA/DC, William Jefferson Clinton West Building, Room B102, 1301 Constitution Ave. NW., Washington, DC. This Docket Facility is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202) 566-1744, and the telephone number for the Air Docket is (202) 566-1742.

FOR FURTHER INFORMATION CONTACT:

For information concerning this proposal, contact Ms. Hillary Ward, Fuels and Incineration Group, Sector Policies and Programs Division, Office of Air Quality Planning and Standards (E143-05), Environmental Protection Agency, Research Triangle Park, NC 27711; telephone number: (919) 541-3154; fax number: (919) 541-0246; email address:

ward.hillary@epa.gov.

SUPPLEMENTARY INFORMATION:

World Wide Web (WWW).

In addition to being available in the docket, an electronic copy of proposed subpart XXX for 40 CFR part 60 is available on the Technology Transfer Network (TTN) Web site. Following signature, the EPA will post a copy of the proposed subpart XXX on the TTN's policy and guidance page for newly proposed or promulgated rules at

http://www.epa.gov/ttnatw01/landfill/landflpg.html.

The TTN provides information and technology exchange in various areas of air pollution control.

Acronyms and Abbreviations.

The following acronyms and abbreviations are used in this document.

ANPRM Advance notice of proposed rulemaking

ANSI American National Standards Institute

BMP Best management practice

BSER Best system of emission reduction

CAA Clean Air Act

CBI Confidential business information

CDX Central Data Exchange

CEDRI Compliance and Emissions Data Reporting Interface

CFR Code of Federal Regulations

CO

2

Carbon dioxide

CO

2

e Carbon dioxide equivalent

CRDS Cavity ringdown spectroscopy

DOC Degradable organic carbon

EPA Environmental Protection Agency

ERT Electronic Reporting Tool

FLIR Forward-looking infrared

FTIR Fourier Transform Infrared

GCCS Gas collection and control system

GHGRP  Greenhouse Gas Reporting Program

GWP Global warming potential

HAP Hazardous air pollutants

ICR Information collection request

IRIS Integrated Risk Information System

lb/MMBtu Pounds per million British thermal unit

LFG Landfill gas

LFGCost Landfill Gas Energy Cost Model

LMOP Landfill Methane Outreach Program

m

3

Cubic meters

Mg Megagram

Mg/yr Megagram per year

MSW Municipal solid waste

MW Megawatt

MWh Megawatt hour

NAICS North American Industry Classification System

NMOC Nonmethane organic compound

NSPS New source performance standards

NSR New Source Review

NTTAA National Technology Transfer and Advancement Act

OAQPS Office of Air Quality Planning and Standards

OMB Office of Management & Budget

ppm Parts per million

ppmvd Parts per million by dry volume

RCRA Resource Conservation and Recovery Act

RFA Regulatory Flexibility Act

RIA Regulatory impacts analysis

RPM Radial plume mapping

SBAR Small Business Advocacy Review

SER Small entity representative

SISNOSE Significant impact on a substantial number of small entities

SSM Startup, shutdown and malfunction

TDL Tunable diode laser

tpy Tons per year

TTN Technology Transfer Network

USG U.S. government

VCS Voluntary consensus standard

VOC Volatile organic compound

WWW World Wide Web

Organization of This Document.

The following outline is provided to aid in locating information in this preamble.

I. Executive Summary

A. Purpose of Regulatory Action

B. Summary of Major Provisions

C. Costs and Benefits

II. General Information

A. Does this action apply to me?

B. What should I consider as I prepare my comments?

III. Background

A. Legal Authority

B. What is the purpose and scope of this action?

C. Where in the Code of Federal Regulations will these changes appear?

IV. Summary of Proposed Changes Based on Periodic Review of the MSW Landfills NSPS Under the CAA

V. What analyses did the EPA conduct to determine BSER?

A. Review of Control Technology

B. What data and control criteria did the EPA consider in evaluating potential changes to the timing of installing, expanding, and removing the GCCS?

C. What control options did the EPA consider?

D. What are the implementation concerns with changing the design capacity criteria?

E. What are the implementation concerns with reducing the NMOC threshold?

F. What are the implementation concerns with shortening the initial or expansion lag times?

G. Request for Comment on BSER

VI. Rationale for the Proposed Changes Based on Review of the NSPS

A. What are the environmental impacts and costs associated with the baseline?

B. How did the EPA determine which control option to propose?

VII. Summary of Clarifications and Resolutions That Are the Result of Implementation Activity

A. Definitions for Treated Landfill Gas and Treatment System and Treatment System Monitoring

B. Startup, Shutdown and Malfunction Provisions

C. Closed Areas

D. Surface Monitoring

E. Electronic Reporting

F. Wellhead Monitoring Requirements

G. Requirements for Updating the Design Plan

H. Submitting Corrective Action Timeline Requests

I. Other Corrections and Clarifications

VIII. Rationale for the Clarifications and Resolutions That Are the Result of Implementation Activity

A. Definitions for Treated Landfill Gas and Treatment System and Treatment System Monitoring

B. Startup, Shutdown and Malfunction Provisions

C. Closed Areas

D. Surface Monitoring

E. Electronic Reporting

F. Wellhead Monitoring Requirements

G. Requirements for Updating Design Plan

H. Submitting Corrective Action Timeline Requests

I. Other Corrections and Clarifications

IX. Request for Comment on Specific Provisions

A. Definitions for Treated Landfill Gas and Treatment System and Treatment System Monitoring

B. Wellhead Monitoring Requirements

C. Enhanced Surface Monitoring Requirements

D. Alternative Emission Threshold Determination Techniques

X. Impacts of Proposed Revisions

A. What are the air quality impacts?

B. What are the water quality and solid waste impacts?

C. What are the secondary air impacts?

D. What are the energy impacts?

E. What are the cost impacts?

F. What are the economic impacts?

G. What are the benefits?

H. What are the health and welfare effects of LFG emissions?

XI. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive Order 13563: Improving Regulation and Regulatory Review

B. Paperwork Reduction Act

C. Regulatory Flexibility Act

D. Unfunded Mandates Reform Act

E. Executive Order 13132: Federalism

F. Executive Order 13175: Consultation and Coordination with Indian Tribal Governments

G. Executive Order 13045: Protection of Children From Environmental Health Risks and Safety Risks

H. Executive Order 13211: Actions that Significantly Affect Energy Supply, Distribution, or Use

I. National Technology Transfer and Advancement Act

J. Executive Order 12898: Federal Actions to Address Environmental Justice in Minority Populations and Low-Income Populations

I. Executive Summary

A. Purpose of Regulatory Action

The EPA has conducted an initial review of the Standards of Performance for Municipal Solid Waste Landfills (landfill new source performance standards or landfills NSPS). The EPA's review is ongoing and will be informed by, among other matters, comments received on today's proposed action. Based on its initial review, the EPA is proposing a number of changes to the existing landfills NSPS. In order to avoid possible confusion regarding which MSW landfills would actually be subject to any revised, or new, requirements, the EPA is establishing a new subpart XXX (40 CFR part 60, subpart XXX) rather than merely updating existing subpart WWW (40 CFR part 60, subpart WWW). The requirements in new subpart XXX will apply to MSW landfills for which construction, modification, or reconstruction is commenced on or after July 17, 2014. The requirements in subpart WWW will continue to apply to MSW landfills on which construction, modification or reconstruction was commenced on or after May 30, 1991 and before July 17, 2014. Note that this preamble uses both of the terms “MSW landfills” and “landfills” to refer to MSW landfills.

1. Need for Regulatory Action

Several factors led to today's proposed action. First, section 111 of the Clean Air Act (CAA) (42 U.S.C. § 7411) requires the EPA to review standards of performance at least every 8 years and, if appropriate, revise the standards to reflect improvements in methods for reducing emissions. Second, a mandatory duty lawsuit was filed against EPA for failure to review the NSPS by the statutorily required deadline. Under a consent decree resolving that lawsuit, the EPA agreed to propose a review and take final action on the proposal. Third, the EPA has concluded that landfill owners and operators, as well as regulators, need clarification regarding issues that have arisen during implementation of the existing standards. Implementation issues include the definition of landfill gas treatment, among other topics.

2. Legal Authority

CAA section 111(b)(1)(B) (42 U.S.C. § 7411(b)(1)(B)) requires the EPA to “at least every 8 years review and, if appropriate, revise” new source performance standards. CAA section 111(a)(1) (42 U.S.C. § 7411(a)(1)) provides that performance standards are to “reflect the degree of emission limitation achievable through the application of the best system of emission reduction which (taking into account the cost of achieving such reduction and any nonair quality health and environmental impact and energy requirements) the Administrator determines has been adequately demonstrated.” We refer to this level of control as the best system of emission reduction or “BSER.”

As indicated above, the EPA has decided to propose its review of the landfill NSPS in a new subpart rather than update existing requirements in 40 CFR part 60, subpart WWW. The EPA believes that either approach is legally permissible.

1

Proposed subpart XXX would appear in 40 CFR part 60 and would apply to landfills that commence construction, reconstruction, or modification on or after July 17, 2014.

1

The EPA believes that it has the legal authority in updating an NSPS to either propose and make changes to the existing subpart or to promulgate a new subpart and has previously done both. In either case, any substantive changes to the NSPS will apply only to sources for which construction, reconstruction, or modification commenced on or after the date on which the proposed changes were published in the

Federal Register

.

B. Summary of Major Provisions

The proposed new subpart retains the same design capacity threshold but reduces the non-methane organic compounds (NMOC) emission threshold at which MSW landfills must install controls. The new subpart also resolves or clarifies issues that the EPA and stakeholders identified during implementation of the current landfills NSPS.

Thresholds for installing controls.

Under the current NSPS, an MSW landfill that has a design capacity of 2.5 million megagrams (Mg) and 2.5 million cubic meters (m

3

) must install and start up a gas collection control system within 30 months after landfill gas emissions reach or exceed a level of 50 Mg NMOC per year. (A megagram is also known as a metric ton, which is equal to 1.1 U.S. short tons or about 2,205 pounds.) The current NSPS is referred to as the “baseline” in this document. Proposed subpart XXX retains the same design capacity threshold as the baseline, but reduces the NMOC emission threshold to 40 Mg/yr. The owner or operator of a landfill may control the gas by routing it to a non-enclosed flare, an enclosed combustion device, or a treatment system that processes the collected gas for subsequent sale or beneficial use.

Landfill gas treatment.

The EPA is addressing two issues related to landfill gas treatment. First, the EPA is proposing to clarify that the use of treated landfill gas is not limited to use as a fuel for a stationary combustion device but also allows other beneficial uses such as vehicle fuel, production of high-Btu gas for pipeline injection, and use as a raw material in a chemical manufacturing process. Second, the EPA is proposing to clarify what constitutes landfill gas treatment. For filtration and dewatering, the definition contains specific numerical values that would provide long-term protection of the combustion equipment, which would support good combustion. We are also proposing to clarify monitoring, recordkeeping, and reporting requirements for treatment systems.

Startup, shutdown and malfunction.

In today's action, the EPA is proposing that the standards in proposed subpart XXX apply at all times, including periods of startup or shutdown, and periods of malfunction. In addition, to enable the EPA to determine the severity of an emissions exceedance for periods when the gas collection system or a control device is not operating, the EPA is proposing to add a recordkeeping and reporting requirement for landfill owners or operators to estimate emissions during such periods.

Other clarifications.

The EPA is proposing other clarifications to address issues that have been raised by landfill owners or operators during implementation of the current NSPS. These other clarifications include improvements to criteria for exempting areas from collection and control, adding criteria for when an affected source must update its design plan, and clarifying when landfill owners or operators must submit corrective action timeline requests. We intend to address

clarifications and other implementation issues for existing landfills in a separate rulemaking.

C. Costs and Benefits

An MSW landfill owner or operator is expected to install the least-cost control for collecting and combusting landfill gas. The control costs include the costs to install and operate a GCCS. For certain landfills that were expected to generate revenue by using the landfill gas for energy, revenue from electricity sales was incorporated into the net control costs. The annualized costs also include testing and monitoring costs.

Proposed subpart XXX, which tightens the NMOC emissions threshold from 50 to 40 Mg/yr NMOC, would achieve reductions of 79 Mg NMOC/yr and 12,300 Mg methane/yr (about 307,600 Mg CO

2

e/yr) beyond the baseline in year 2023. The associated annualized net cost for proposed subpart XXX is estimated to be an additional $471,000 (2012$) in 2023. The EPA expects that the avoided emissions will result in improvements in air quality and reduce health effects associated with exposure to air pollution related emissions, and result in climate co-benefits due to reductions of the methane component of landfill gas. However, because this rulemaking is not an “economically significant regulatory action” under Executive Order 12866 because it is not likely to have an annual effect on the economy of $100 million or more, we have not conducted a Regulatory Impact Analysis (RIA) or a benefits analysis. The baseline NSPS in effect today is estimated to achieve a reduction of 610 Mg/yr NMOC and 94,800 Mg/yr methane (about 2.4 million Mg/yr CO

2

e) in 2023, compared to the absence of control (see section VI.A. of this preamble and the Economic Impact Analysis for more detail). The associated annualized net cost of the baseline is estimated to be $2.7 million ($2012) in 2023.

II. General Information

A. Does this action apply to me?

This proposal affects municipal solid waste (MSW) landfills and associated solid waste management programs. Affected categories and entities include those listed in Table 1 of this preamble.

Table 1—Regulated Entities

Category

NAICS

a

Examples of affected facilities

Industry: Air and water resource and solid waste management

924110

Solid waste landfills.

Industry: Refuse systems—solid waste landfills

562212

Solid waste landfills.

State, local, and tribal government agencies

924110

Administration of air and water resource and solid waste management programs.

a

North American Industry Classification System.

This table is not intended to be exhaustive but rather provides a guide for readers regarding entities likely to be regulated by the new subpart. To determine whether your facility would be regulated by this action, you should carefully examine the applicability criteria in proposed 40 CFR 60.760 of subpart XXX. If you have any questions regarding the applicability of the proposed subpart to a particular entity, contact the person listed in the preceding

FOR FURTHER INFORMATION CONTACT

section.

B. What should I consider as I prepare my comments?

1. Submitting CBI

Clearly mark the part or all of the information that you claim to be CBI. For CBI information in a disk or CD ROM that you mail to the EPA, mark the outside of the disk or CD ROM as CBI and then identify electronically within the disk or CD ROM the specific information that is claimed as CBI. In addition to one complete version of the comment that includes information claimed as CBI, a copy of the comment that does not contain the information claimed as CBI must be submitted for inclusion in the public docket. Information marked as CBI will not be disclosed except in accordance with procedures set forth in 40 CFR part 2.

Do not submit information that you consider to be CBI or otherwise protected through

http://www.regulations.gov

or email. Send or deliver information identified as CBI to only the following address: Mr. Roberto Morales, OAQPS Document Control Officer (Room C404-02), U.S. EPA, Research Triangle Park, NC 27711, Attention Docket ID No. EPA-HQ-OAR-2003-0215.

If you have any questions about CBI or the procedures for claiming CBI, please consult the person identified in the

FOR FURTHER INFORMATION CONTACT

section.

2. Docket

The docket number for the municipal solid waste landfills new source performance standards (40 CFR part 60, subpart XXX) is Docket ID No. EPA-HQ-OAR-2003-0215. Docket ID No. A-88-09 contains supporting information for related 40 CFR part 60, subparts WWW and Cc.

III. Background

In June 2013, President Obama issued a Climate Action Plan which, among other matters, directed the EPA and five other federal agencies to develop a comprehensive interagency strategy to reduce methane emissions. The plan recognized that methane emissions constitute a significant percentage of domestic greenhouse gas (GHG) emissions, highlighted reductions in methane emissions since 1990, and outlined specific actions that could be taken to achieve additional progress. Specifically, the federal agencies were instructed to focus on “assessing current emissions data, addressing data gaps, identifying technologies and best practices for reducing emissions and identifying existing authorities and incentive-based opportunities to reduce methane emissions.”

As a follow up to the 2013 Climate Action Plan, the Climate Action Plan: Strategy to Reduce Methane Emissions (the Methane Strategy) was released in March 2014. The focus on reducing methane emissions is due to the fact that methane is a potent GHG with a global warming potential that is 25 times greater than carbon dioxide.

2

Methane has an atmospheric life of 12 years, and because of its potency as a GHG and its atmospheric life, reducing methane emissions achieves a near-term beneficial impact in mitigating global climate change.

2

IPCC Fourth Assessment Report (AR4), 2007. Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, Pachauri, R.K. and Reisinger, A. (eds.)]. IPCC, Geneva, Switzerland, 104 pp.

The targeted strategy noted that the landfill standards at issue here and voluntary programs already in place

have considerably reduced methane emissions.

3

With respect to landfills, the Methane Strategy directs the agency to build upon progress to date through updates to the EPA's rules for reducing emissions from new, modified, and reconstructed landfills, issuance of an Advance Notice of Proposed Rulemaking (ANPRM) to explore options to address emissions from existing landfills, and encouragement of beneficial use through voluntary programs.

3

Climate Action Plan: Strategy to Reduce Methane Emissions. March 2014. p.5.

http://www.whitehouse.gov/sites/default/files/strategy_to_reduce_methane_emissions_2014-03-28_final.pdf

.

The EPA has long recognized the climate benefits associated with reducing methane emissions from landfills. In the 1991 Landfill NSPS Background Information Document

4

the EPA noted that reduction of methane emissions from MSW landfills is one of the many options available to reduce possible global warming. When the EPA promulgated the NSPS for MSW landfills, which regulates MSW landfill emissions (commonly referred to as landfill gas), in 1996, the EPA noted the co-benefits of controlling methane, but recognized the then relatively limited understanding of GHG and their effect on global climate change (61 FR 9917, March 12, 1996). In 1996, we stated:

4

Air Emissions from Municipal Solid Waste Landfills—Background Information for Proposed Standards and Guidelines, U.S. EPA (EPA-450/3-90-011a) (NTIS PB 91-197061) page 2-15.

An ancillary benefit from regulating air emissions from MSW landfills is a reduction in the contribution of MSW landfill emissions to global emissions of methane. Methane is a major greenhouse gas, and is 20 to 30 times more potent than CO

2

on a molecule-per-molecule basis. There is a general concern within the scientific community that the increasing emissions of greenhouse gases could lead to climate change, although the rate and magnitude of these changes are uncertain.

Since 1996, the EPA and the scientific community have gained a better understanding of GHGs, such as methane, and their effects on climate change and human health and welfare. In 2009, the EPA Administrator issued the document known as the Endangerment Finding under CAA section 202(a)(1).

5

In the Endangerment Finding, which focused on public health and public welfare impacts within the United States, the Administrator found that elevated concentrations of GHGs in the atmosphere may reasonably be anticipated to endanger the public health and welfare of current and future generations.

5

“Endangerment and Cause or Contribute Findings for Greenhouse Gases Under Section 202(a) of the Clean Air Act,” 74 FR 66496 (December 15, 2009) (“Endangerment Finding”).

There is now scientific consensus that GHGs affect climate change and, as recognized by the President in the Methane Strategy, this scientific consensus increases the need for the EPA to examine regulatory options for reducing methane emissions. The EPA is currently reviewing the MSW Landfills NSPS in light of the President's Climate Action Plan, the Methane Strategy, and improvements in the science related to GHG emissions, and is exploring opportunities to achieve additional reductions in emissions, including methane emissions.

A. Legal Authority

Section 111 of the Clean Air Act (CAA) requires the EPA Administrator to list categories of stationary sources that in the Administrator's judgment cause or contribute significantly to air pollution that may reasonably be anticipated to endanger public health or welfare. 42 U.S.C. § 7411(b)(1)(A). The EPA must then issue performance standards for new (and modified or reconstructed) sources in each source category. 42 U.S.C. § 7411(b)(1)(B). These standards are referred to as new source performance standards or NSPS. The EPA has the authority to define the scope of the source categories, determine the pollutants for which standards should be developed, set the emission level of the standards, and distinguish among classes, type and sizes within categories in establishing the standards. 42 U.S.C. § 7411(b).

On March 12, 1996 (61 FR 9905), under the authority of CAA section 111(b)(1)(A), the EPA added the MSW landfills source category to the priority list in 40 CFR 60.16 because, in the judgment of the Administrator, the source category contributes significantly to air pollution that may reasonably be anticipated to endanger public health and welfare. In that same notice, the EPA promulgated new source performance standards, which apply to new (and modified or reconstructed) landfills under the authority of CAA section 111(b)(1)(B), and emission guidelines, which apply to existing landfills, under the authority of CAA section 111(d). In the March 12, 1996 notice, the EPA defined the MSW landfills source category, identified municipal solid waste landfill emissions (commonly referred to as landfill gas) as the pollutant for which standards should be developed, identified which landfills would be covered, and determined the applicability thresholds and emission level of the standards.

CAA section 111(a)(1) (42 U.S.C. § 7411(a)(1)) provides that standards of performance are to “reflect the degree of emission limitation achievable through the application of the best system of emission reduction which (taking into account the cost of achieving such reduction and any nonair quality health and environmental impact and energy requirements) the Administrator determines has been adequately demonstrated.” We refer to this level of control as the best system of emission reduction or BSER. When promulgated in 1996, BSER for MSW landfills was determined to be a well designed and well operated LFG collection and control system with a control device capable of reducing NMOC by 98 percent by weight. NMOC was established as a surrogate for LFG in the final rule.

The CAA also requires the EPA to review the NSPS at least every 8 years to determine if the level of control that was previously established remains appropriate. Specifically, CAA section 111(b)(1)(B) (42 U.S.C. § 7411(b)(1)(B)) requires the EPA to “at least every 8 years review and, if appropriate, revise” standards of performance. The Administrator need not review a standard, however, if the “Administrator determines that such review is not appropriate in light of readily available information on the efficacy” of the standard. While not required to do so, the EPA has authority to revise an NSPS to add emission limits for pollutants or emission sources not currently regulated for that source category concurrent with its review of the NSPS (77 FR 49494, August 16, 2012).

In determining BSER, we typically conduct a review that identifies what emission reduction systems exist and how much they reduce air pollution in practice. Next, for each control system identified, we evaluate its costs, energy requirements, and any nonair quality health and environmental impacts. Based on our evaluation, we determine BSER for each pollutant to be regulated and establish an appropriate standard of performance based on the identified BSER. The resultant standard is usually expressed either as a numerical emissions limit, e.g., parts per million (ppm) or pounds per million British thermal unit (lb/MMBtu), or a percent reduction requirement. Although the standards are based on the identified BSER, the EPA may not require the use of a particular technology to comply with a performance standard unless the Administrator determines that it is not

feasible to prescribe or enforce a standard of performance. (CAA 111(b)(5), 42 U.S.C. 7411(b)(5).) Thus, except in rare circumstances, sources remain free to select any control measures that will meet the requirements of the standard(s). Upon promulgation, an NSPS becomes a national standard with which all new, reconstructed, and modified sources must comply. (CAA 111(e), 42 U.S.C. 7411(e).)

B. What is the purpose and scope of this action?

The purpose of this action is (1) to review the MSW landfills NSPS, (2) to propose a resolution or to provide clarification regarding implementation issues that were addressed in prior proposed rules published on May 23, 2002 (67 FR 36475) and September 8, 2006 (71 FR 53271), as they apply to new sources, and (3) to take comment on specific aspects of EPA's review that will be considered in promulgating the final NSPS standard. These proposed revisions appear in the proposed 40 CFR part 60 subpart XXX.

Many changes have occurred in the landfill industry since the landfills NSPS was originally promulgated in 1996 that have necessitated this review. Among the factors contributing to the need for review are the following: Changes in landfill characteristics (i.e., size, ownership, age) and population; proliferation of landfill gas energy projects; the availability of more comprehensive data on landfills from mandatory (Greenhouse Gas Reporting Program (GHGRP)) and voluntary EPA programs; and the introduction of new techniques for monitoring landfill gas emissions. The number and size distribution of MSW landfills in the United States has also evolved since 1996. Public opposition to local MSW disposal facilities and the increasing cost of disposal at locations near where the waste is generated have resulted in consolidation and led to an increase in long-distance hauls to large regional landfills. As a result, the corresponding emission profiles and per landfill compliance costs have also changed.

The number of landfill gas to energy projects has also increased substantially. In 1996, there were approximately 160 operational landfill gas energy projects and approximately 700 candidate landfills according to data obtained by the EPA Landfill Methane Outreach Program (LMOP). According to LMOP, as of March 2014, there were 636 operational projects using landfill gas to produce energy and 450 landfills that remain candidates for energy recovery. LMOP is a voluntary assistance program that encourages recovery and beneficial use of landfill gas, and in turn, helps to reduce methane emissions from landfills. During our review, the EPA has also become aware of techniques and procedures for monitoring landfill gas emissions that were not available at the time of the original rule.

The EPA is required to review the MSW Landfills NSPS and sections IV, V, and VI of this preamble present our initial determinations. In addition, the EPA has determined that it is appropriate to propose a revised NSPS based on these initial determinations.

This action also provides clarification regarding issues that arose during the implementation of the current landfills regulations and proposes regulatory text addressing some of those issues. We addressed these issues in previous notices as published on May 23, 2002 (67 FR 36475) and September 8, 2006 (71 FR 53271). These issues include the definition of landfill gas treatment and other topics such as surface monitoring, how to address closed areas of landfills and when to allow removal of controls. Although the cited notices addressed these issues in the context of subparts Cc and WWW, the clarifications and resolutions discussed in sections VII and VIII of this preamble would affect only landfills that commence construction, reconstruction, or modification on or after July 17, 2014.

The EPA plans to address amendments and clarifications resulting from implementation activities for landfills subject to 40 CFR part 60, subpart WWW and state or federal plans implementing subpart Cc in a separate action.

This action also requests comment on specific aspects of the EPA's review, the consideration of which will be integral to the EPA in taking final action to promulgate a new NSPS. These provisions include landfill gas treatment, wellhead monitoring, and surface monitoring. See section IX of this preamble for a discussion of those provisions.

C. Where in the Code of Federal Regulations will these changes appear?

The EPA is proposing to add new subpart XXX to 40 CFR part 60. Subpart XXX would apply to landfills that commence construction, reconstruction, or modification on or after July 17, 2014. Proposed subpart XXX in 40 CFR part 60 contains a revision to the NMOC emission rate threshold, as well as provisions that provide clarification and proposed resolutions to technical and implementation issues.

IV. Summary of Proposed Changes Based on Periodic Review of the MSW Landfills NSPS Under the CAA

The EPA is proposing to reduce the NMOC emission rate threshold for installing and operating a gas collection and control system to 40 Mg/yr from the current NSPS level of 50 Mg/yr. The proposal retains the design capacity cutoff of 2.5 million Mg and 2.5 million cubic meters that appears in subpart WWW. See sections V and VI of this preamble for a discussion of the proposed rule changes. The new subpart also resolves or clarifies issues that the EPA and stakeholders identified during implementation of the current landfills NSPS.

The EPA is proposing this revised emission threshold that takes into account the total methane emission reductions that can be achieved in addition to the reductions of NMOC emissions that are realized when the GCCS is installed at an earlier point in time. While the proposal continues to require measurement of NMOC as a surrogate for landfill gas, the EPA asserts that the methane reductions achieved are consistent with the President's Methane Strategy as described in section III of this preamble.

V. What analyses did the EPA conduct to determine BSER?

The EPA first undertook a review to determine whether a well designed and well operated landfill GCCS, which EPA previously determined was BSER for controlling landfill gas, remains BSER for that purpose. The EPA considered GCCSs, as well as other emission control technologies that are either currently in place at landfills, or could be adopted, and considered the emission reductions achieved by those systems. Based on this analysis, the EPA determined that a well designed and operated landfill GCCS remains BSER. The EPA then undertook an analysis to determine whether applying the existing criteria for installing and operating a landfill GCCS to the expected population of new MSW landfills remains the preferred approach to implementing BSER. To do so, the EPA developed and applied a model program in Microsoft® Access to revisit the design capacity cutoff, the NMOC emission rate cutoff, and the time allowed for installing and expanding a gas collection system. In addition to reviewing the thresholds that determine the schedule for installing and expanding the GCCS system, the EPA also reviewed whether the schedule for removing the GCCS needed adjustment (see section V.A of this preamble). For

the above analyses, the EPA compared the environmental benefits and corresponding costs that are expected to be achieved under various control options to the environmental benefits and corresponding costs that are expected to be achieved under the baseline.

A. Review of Control Technology

Prior to promulgation of the MSW landfills NSPS (40 CFR part 60, subpart WWW) in 1996, we conducted a review that identified the existing types of emission control systems being used and the corresponding emission reductions that were being achieved in practice. Based on that evaluation, we determined BSER to be: (1) A well designed and well operated landfill GCCS and (2) a control device capable of reducing NMOC in the collected gas by 98 percent by weight (56 FR 24468, May 30, 1991 and 61 FR 9914, March 12, 1996). For BSER, we set design and operating standards for the gas collection system and set an emission limit for the control system. Then, we established a schedule for installing and then expanding the GCCS based on the landfill's design capacity (2.5 million megagrams and 2.5 million cubic meters) and the estimated NMOC emissions rate (50 Mg/yr).

The current technology review shows that the same types of collection and control systems reviewed in 1996 (see Docket ID No. A-88-09) continue to be prominently used to reduce landfill gas emissions and the design and operational standards promulgated in 1996 continue to be robust. Section VI of this preamble discusses our findings resulting from consideration of potential revisions affecting the criteria and schedule for installing and then expanding the GCCS. We undertook this evaluation to determine if the thresholds associated with BSER established in 1996 are still relevant today, “taking into account the cost of achieving such reduction and any non-air quality health and environmental impact and energy requirements” in accordance with CAA section 111(a)(1).

In 1996, the EPA set design and operational standards in subpart WWW for the GCCS and an emission limit for the control device (61 FR 9907; March 12, 1996).

6

Subpart WWW established design criteria for both horizontal and vertical collection systems because both types of systems are used. The criteria ensure that owners and operators design, construct, and operate gas collection systems to maximize collection and minimize emissions of landfill gas. Landfill GCCS designed according to these criteria are expected to, at a minimum: (1) Be capable of handling the maximum gas generation rate, (2) have a design that provides for monitoring and adjusting the operation of the system, (3) be able to collect gas effectively from all areas of the landfill that warrant control, and (4) be expandable through the addition of further collection system components to collect gas from new areas of the landfill as they require control. Within 1 year of reaching or exceeding an NMOC emission rate of 50 Mg/yr, landfill owners and operators must submit (or update in the case of modification or reconstruction) a collection and control system design plan prepared by a professional engineer to the EPA or delegated authority for approval.

6

In developing the current NSPS, the EPA determined that in order to set a performance standard such as a collection efficiency for the gas collection system it would be necessary to quantify the landfill gas available for collection in comparison to the amount collected and that it was not technically feasible to measure the amount of gas available for collection. On that basis, the EPA concluded that it was necessary to establish a design and operation standard for the gas collection system (56 FR 24484, May 30, 1991).

Gas collection system technology review.

Our review shows that a gas collection system comprising gas collection wells, horizontal or vertical piping, and blowers continues to be the most common technology used to collect landfill gas, regardless of whether a landfill is complying with subpart WWW, state or local regulations, or voluntarily controlling landfill gas for other reasons. Landfills continue to collect landfill gas using gas collection systems that are similar to the types of systems described in the background information of the 1996 landfill NSPS and emission guidelines proposal.

7

As of 2013, hundreds of landfills have installed collection systems to comply with subpart WWW. The EPA is also aware that many landfill owners and operators have installed collection systems on a voluntary basis. As of 2013, approximately 500 landfills voluntarily collect and control landfill gas using the same technologies required by subpart WWW. The EPA estimated this number by comparing the list of landfills that are modeled to have installed a GCCS in 2014 in the NSPS/EG dataset to the list of landfills that are reported to have a GCCS installed in the LMOP database. See section V.B of this preamble for a discussion of the dataset of landfills and corresponding model that the EPA used to examine the potential impact of changes to the landfills NSPS. The LMOP database is a voluntary national database of landfills and landfill gas energy projects, including information on which landfills have a GCCS in place.

7

Air Emissions from Municipal Solid Waste Landfills-Background Information for Proposed Standards and Guidelines, U.S. EPA (EPA-450/3-90-011a) (NTIS PB 91-197061).

Landfill owners and operators collect landfill gas for a variety of reasons: To control odor, to minimize fire and explosion hazards, to recover landfill gas to be used for energy recovery, to sell carbon credits, and to comply with local, state, or federal air quality standards. Landfill owners and operators are motivated to design and operate their landfill gas collection systems to efficiently collect and control landfill gas and they continue to install a gas collection system comprising gas collection wells, horizontal or vertical piping, and blowers to collect and control landfill gas.

Gas collection system as BSER.

For this NSPS review, the EPA is proposing that the combination of design and operational criteria in subpart WWW continue to ensure that the collection system efficiently collects landfill gas and that a gas collection and control system meeting these criteria continues to represent BSER for MSW landfills that commence construction, reconstruction, or modification after July 17, 2014. The EPA is also proposing that a combined design and operation standard for the gas collection system remains the best format for the rule. In developing subpart WWW, the EPA determined that in order to set a performance standard such as a collection efficiency for the gas collection system it would be necessary to quantify the landfill gas available for collection in comparison to the amount collected and that it was not technically feasible to measure the amount of gas available for collection. On that basis, the EPA concluded that it was necessary to establish a design and operation standard for the gas collection system (56 FR 24484, May 30, 1991). The EPA has not determined that the circumstances have changed so as to require the establishment of a standard of performance for the gas collection system. (CAA section 111(h)(3), 42 U.S.C. 7411(h)(3).) Therefore, for the gas collection system, the EPA proposes to maintain the design and operational standards in subpart WWW in subpart XXX.

Gas control system technology review.

As part of the BSER review prior to promulgation of subpart WWW in 1996, we conducted a technology review that identified the existing types of emission control systems, emerging technologies, and the emission reductions achieved in

practice by those systems. Properly operated GCCS reducing NMOC by 98 percent by weight had been demonstrated on landfills of the size affected by subpart WWW. The EPA selected a reduction of 98 percent as the level representing BSER for control of landfill gas because this is the level achievable by demonstrated technologies. Based on this analysis, the EPA selected 98 percent reduction, expressed as a performance level (i.e., a rate-based standard or percent control), as the appropriate BSER-based standard. The EPA determined that this level was reasonable considering costs, nonair quality health and environmental impacts, and energy requirements.

8

Subpart XXX, therefore, requires all control devices to demonstrate 98 percent reduction by weight of NMOC or an outlet concentration of 20 ppmvd of NMOC, as hexane. Enclosed combustion devices have the option of reducing emissions to 20 parts per million, dry volume.

8

Air Emissions from Municipal Solid Waste Landfills—Background Information for Final Standards and Guidelines, EPA-453/R-94-021. EPA Office of Air and Radiation/Office of Air Quality Planning and Standards, Emission Standards Division, December 1995, page 2-79.

Each of the estimated 1,000 gas collection systems in place today, both required and voluntary, has an associated combustion device used to control emissions of landfill gas. At a minimum, landfills employ a flare to combust the gas. Both open and enclosed flares were determined to be among BSER combustion devices and these technologies continue to be used today. The following combustion controls can achieve at least 98 percent destruction of NMOCs and we propose that they continue to represent BSER: Enclosed flares and incinerators, and devices that burn landfill gas to recover energy, such as boilers, turbines, and internal combustion engines. The EPA continues to believe that 98 percent reduction is appropriate because this continues to be the level achievable by demonstrated technologies. Current data are consistent with 98 percent destruction. However, we request comment and additional data on the NMOC destruction efficiency of incinerators and devices that burn landfill gas to recover energy, such as boilers, turbines, and internal combustion engines.

Non-enclosed flares used at landfills meeting the criteria in 40 CFR 60.18(b) are thought to have destruction efficiencies similar to enclosed flares and incinerators, and devices that burn landfill gas to recover energy, such as boilers, turbines, and internal combustion engines. However, in April 2012 the EPA conducted an external peer review on flaring efficiency and made available to the public a draft technical report, “Parameters for Properly Designed and Operated Flares.”

9

In this report, the EPA evaluated test data and identified a variety of parameters that may affect flare performance and that could be monitored to help assure good combustion efficiency. Nevertheless, none of the flare performance data used in this report comes from flares used at MSW landfills, and it does not provide any new test data on non-assisted flare types, which, to our knowledge, are the only non-enclosed flare type found in this source category. Thus, while we have no new information to suggest that flares at MSW landfills complying with 40 CFR 60.18(b) will not achieve at least 98 percent destruction of NMOCs (and methane), we solicit comments and additional information on flare performance specifically for this source category in order to determine whether non-enclosed flares continue to represent BSER for new landfills. Examples of information requested for this source category include: Prevalence of flaring; number and types of flares used; waste gas characteristics such as flow rate, composition and heat content; use of flare gas recovery and other flare emission minimization practices; and existing flare monitoring systems.

9

U.S. EPA, Parameters for Properly Designed and Operated Flares, Report for Flare Review Panel, April 2012.

http://www.epa.gov/ttn/atw/flare/2012flaretechreport.pdf

.

Gas control system as BSER.

Based on the above, for this stage of the NSPS review, the EPA has determined that a control system designed and operated within the parameters demonstrated in the performance test to reduce NMOC (and, in turn, methane) by 98 percent by weight or reduction to 20 parts per million by volume, continues to represent BSER for controlling landfill gas emissions. Therefore, the EPA proposes in subpart XXX to maintain the current performance standard from subpart WWW for the gas control system.

Other current technologies.

The EPA is also considering emission control technologies or practices other than GCCS that are currently in place as part of its review. The EPA qualitatively evaluated the emission reductions achieved by those systems in practice and also considered whether such technologies or practices could be relied upon in establishing a standard of performance under CAA section 111.

The EPA reviewed several best management practices (BMPs) for GCCS that may achieve greater reductions in landfill gas emissions than a well designed and well operated system alone. The EPA reviewed these BMPs to determine if and how they could be incorporated into subpart XXX in conjunction with the current performance-based standard.

One BMP the EPA considered was collecting landfill gas from leachate removal systems in order to control landfill gas that exists below the waste mass along the bottom of the landfill. The EPA is aware of landfills with leachate recirculation systems that have connected the landfill gas collection system and leachate collection system; however, references suggest that connection of these systems is not common at landfills that do not employ leachate recirculation.

10

The efficiency of capturing LFG emissions through this BMP depends on the efficiency of both the gas collection system and the leachate recirculation system. Proposed 40 CFR 60.762(b)(2)(i)(D) recognizes that leachate collection components may be part of a site-specific collection and control system design plan. Because the design plan is not prescriptive and instead contains design and operational standards that are site-specific, the design plan has the flexibility to include collection of landfill gas from leachate collection systems. However, since we do not currently have sufficient information on the efficacy of collecting gas from leachate removal systems in circumstances that do not include leachate recirculation and since the use of leachate recirculation is not prevalent in the landfill industry, the EPA does not currently consider this BMP to be part of BSER for controlling landfill gas, including methane, emissions. The EPA does, however, request comments on the efficacy and costs of enhancing gas collection systems to collect LFG from leachate removal or storage systems. The EPA also requests comment on the types of landfills currently collecting gas from leachate removal systems and the specifics of the gas collection systems used in practice. The EPA will use this information to evaluate if and when the use of an enhanced gas collection system that collects landfill gas from the leachate removal system may be appropriate.

10

SCS Engineers, Technology and Management Options for Reducing Greenhouse Gas Emissions. Prepared for California Integrated Waste Management Board. Prepared by SCS Engineers. April 2008.

Another BMP the EPA considered is requiring a gas collection system to prevent waterlogged wells, perhaps

through the use of leachate removal pumps. Leachate and condensate can accumulate in collection wells, blocking landfill gas capture. Because a flooded well cannot collect gas, fixing a flooded well would have a high emission reduction potential. Wellhead operating parameters in proposed subpart XXX require that each owner or operator of an MSW landfill either operate the collection system with a negative pressure at each wellhead or, in areas with a geomembrane or synthetic cover, establish acceptable pressure limits in the design plan. These performance standards would help identify any inoperable wells resulting from flooding. The proposed surface emissions monitoring would also identify any elevated methane levels resulting from an inoperable well. The EPA has determined that the operating requirements in proposed subpart XXX provide a sufficient system to detect and correct waterlogged wells and thus ensure that the gas collection system is well operated.

The EPA does not currently consider requiring that the gas collection system be operated in such a way as to prevent waterlogged wells, rather than requiring that the wells be monitored so as to identify any such wells, to be BSER. Nonetheless, the EPA requests comment on whether the current combination of wellhead monitoring and surface emission monitoring is sufficient for identifying inoperable wells, especially in cases where wells have been installed for a significant amount of time. If the proposed monitoring systems are believed to be deficient for identifying flooded wells, the EPA also asks for comment on whether any additional recordkeeping, such as periodic measurement of liquid levels in gas wells, might be useful in identifying flooded wells that are not collecting gas.

The EPA also considered a BMP of requiring redundant seals and enhanced sealing materials on wellheads. One study includes a forward-looking infrared (FLIR) survey suggesting that landfill gas wellheads and other surface penetrations present high potential for concentrated leaks of organic compounds.

11

The use of advanced seals at wellheads may help to ensure that the well can apply sufficient vacuum to the landfill to facilitate gas extraction while preventing leaks of landfill gas to the atmosphere.

11

ARCADIS. Quantifying Methane Abatement Efficiency at Three Municipal Solid Waste Landfills. Prepared for USEPA/ORD. January 2012.

Proposed subpart XXX requires the preparation of a site-specific design plan by a professional engineer, which must be approved by the EPA or a delegated authority. Because the design plan is not prescriptive and instead contains design and operational standards that are site-specific, the design plan has the flexibility to determine the appropriate number or type of seals in order to accommodate the conditions and climates at different landfills. The EPA believes that this site-specific approach is preferable to specifying the use of a particular number of seals. This site-specific approach also provides for continued flexibility for future design plans to incorporate new sealing materials that may be more efficient than those currently available today. The design plan, coupled with wellhead and surface monitoring requirements, ensures that leaks from wells are minimized.

With this proposal, the EPA is clarifying that all cover penetrations must be checked during quarterly surface monitoring and this clarification would apply to checking around each wellhead for any elevated emission levels. Proposed subpart XXX requires corrective action for any surface monitoring reading over 500 ppm. Finally, the EPA is taking comment on tighter traverse patterns for surface monitoring, coupled with more rigorous surface maintenance activity, as another level of protection against leaks from improperly sealed wells.

Further, one reference indicates that many engineers already require two and sometimes three seals in a well when preparing design plans for GCCS. For all of these reasons, the EPA believes that a site-specific approach is more effective than prescribing the use of a particular number of seals or the use of a particular type of sealing material. As a result, at this point in its review, the EPA has determined that the use of advanced seals is not a component of BSER. The EPA, nevertheless, requests comment on whether the use of advanced seals should be a component of BSER.

The EPA also reviewed several emerging technologies that may achieve additional landfill gas emission reductions. The EPA evaluated whether the technology is adequately demonstrated and the extent to which the technology could be applied to new landfills.

The EPA considered a number of technologies that increase the methane oxidation rate of the landfill, thereby reducing the amount of methane that could escape through the surface of the landfill. Co-oxidation of NMOC has been observed during use of these alternative landfill cover materials, which has the potential to reduce odors and toxic air pollutants.

12

Oxidative covers, including biocovers, use methanotrophic bacteria to oxidize methane into water, carbon dioxide, and biomass. A biocover is an additional layer of final cover that is typically made of two layers, a permeable layer to evenly distribute the landfill gas to the oxidation media, and a layer of oxidation media typically made of soil, compost, or other porous media. While these innovative final cover practices at MSW landfills have the potential for achieving a moderate amount of methane emission reductions, final cover practices are currently addressed under Subtitle D of the Resource Conservation and Recovery Act (RCRA) and not under the CAA. As a result, the EPA does not currently consider them to be BSER; however, research indicates that biocovers may help to reduce emissions of methane, a primary constituent of landfill gas.

12

U.S. EPA. Available and Emerging Technologies for Reducing Greenhouse Gas Emissions from Municipal Solid Waste Landfills. June 2011.

Another method for increasing the oxidation rate is to route passively vented landfill gas through a vessel containing methane-oxidizing media, commonly referred to as a biofiltration cell. Biofilters have been tested for use at landfills over only the past 10 to 15 years, and, although they may achieve moderate to high reductions in uncontrolled methane emissions, we cannot conclude at this time that these systems have been adequately demonstrated, as we explain below.

13 14

Biofiltration cells are feasible for use only at small landfills or landfills with passive gas collection systems due to the size of the biofiltration bed required to treat the mixture of air and landfill gas. New landfills are expected to be large and have active gas collection systems to comply with the requirements in the proposed subpart XXX. In addition, due to the nature of passive gas collection systems, this technology lacks the ability to control and monitor the oxidation of methane in the landfill gas.

15

13

Buske, D. and M. Lannan. The Biofilter Effect on Landfill Gas Capture. 2009 SWANA Landfill Gas Symposium Proceedings.

14

Gebert, J.; and Groengroeft, A., 2006, “Performance of a passively vented field-scale biofilter for the microbial oxidation of landfill methane”.

Waste Management Research

26: 399-407.

15

USEPA. Available and Emerging Technologies for Reducing Greenhouse Gas Emissions from Municipal Solid Waste Landfills. June 2011.

http://www.epa.gov/nsr/ghgdocs/landfills.pdf.

No data exist on the long-term performance, effectiveness, or maintenance requirements of these

systems.

16 17 18

For these reasons, these methane oxidation technologies were not considered to be BSER. However, the EPA is requesting information about application of these technologies to better understand these characteristics for full-scale use of biocovers and biofilters. The EPA is seeking information and data about the long-term performance, effectiveness, and/or maintenance requirements of full-scale use of biocovers and biofilters, as well as comment on appropriate mechanisms to monitor the performance of these alternatives. Comment is also requested on biocover parameters and their effect on oxidation. Such parameters may include depth, soil characteristics, measurement, and their effect on percent oxidation.

16

Ibid.

17

Abichou, T, J. Chanton, D. Powelson, “Field Performance of Biocells, Biocovers, and Biofilters to Mitigate Greenhouse Gas Emissions from Landfills,” State University Systems of Florida, Florida Center for Solid and Hazardous Waste Management March 2006.

18

Yazdani, R, and Imhoff, P. Contractor's report to CalRecycle: Biocovers at Landfills for Methane Emissions Reduction Demonstration. October 2010.

B. What data and control criteria did the EPA consider in evaluating potential changes to the timing of installing, expanding, and removing the GCCS?

To examine the potential impact of changes to the timing of initiating landfill gas collection and control, the EPA developed a dataset of information for existing and new landfills, as described below, and applied a model to assess when controls were needed under the baseline control scenario as well as various regulatory options. Each regulatory option assessed variations in the design capacity and emission rate thresholds, as well as changes to the initial lag time and expansion lag time. The “initial lag time” is the time period between when the landfill exceeds the emission rate threshold and when controls are required to be installed and started up (30 months in subpart WWW). The “expansion lag time” is the amount of time allotted for the landfill to expand the GCCS into new areas of the landfill (5 years for active areas and 2 years for areas that are closed or at final grade in subpart WWW).

The EPA created a dataset of information for existing and new landfills, which included landfill-specific data such as landfill open and closure year, landfill design capacity, landfill design area, and landfill depth. The creation of the landfill dataset is detailed in the docketed memorandum, “Summary of Landfill Dataset Used in the Cost and Emission Reduction Analysis of Landfills Regulations. 2014.”

The EPA used attributes of these existing landfills to develop model landfills to represent new landfills opening in the first 5 years after subpart XXX is proposed (2014-2018). The model future landfills were developed by evaluating the most recently opened existing landfills and assuming that the sizes and locations of landfills opening in the future would be similar to the sizes and locations of landfills that opened in the last 8 years with complete data (2003-2010).

The EPA then incorporated technical landfill parameters from this dataset, such as landfill size, annual waste acceptance rate, and open year, into a model in order to estimate when each landfill would install GCCS under various regulatory options. This model used a first-order decay equation to model the landfill gas emissions (i.e., NMOC and methane) from each landfill for 50 years following the effective date of subpart XXX.

The EPA programmed a Microsoft® Access database to calculate the cost and emission impacts associated with different regulatory options (hereinafter referred to as the “model”). To determine when landfills exceeded regulatory emission thresholds, the model uses Tier 1 default values from subpart WWW for the methane generation potential (L

0

) and the methane generation rate (k), but uses the NMOC concentration in “Compilation of Air Pollutant Emission Factors (AP-42

19

)” for determining when landfills would meet the regulatory NMOC emissions threshold. The Tier 1 default values in subpart WWW for L

0

and k are conservatively high for the purpose of estimating actual emissions; therefore, they are used only for estimating uncontrolled emissions to determine when landfills could exceed the threshold and be required to install controls. For the average NMOC concentration, the model uses the default value specified in AP-42. Subpart WWW allows the use of Tier 2 tests to determine NMOC concentration, and industry experience suggests the majority of landfills have conducted Tier 2 tests and obtained estimates that are consistent with the AP-42 NMOC value; thus, the AP-42 NMOC value was deemed to be more representative than Tier 1 NMOC values for determining when landfills would meet the regulatory NMOC emissions threshold for installing a landfill GCCS.

19

U.S. EPA, AP-42, Fifth Edition, Compilation of Air Pollutant Emission Factors, Volume 1: Stationary Point and Area Sources. 1995.

http://www.epa.gov/ttnchie1/ap42/.

When modeled landfill gas emissions for a particular landfill exceeded the emission rate threshold, the EPA assumed that collection equipment was installed and started operating at the landfill after the initial lag time specified in each option. The EPA also assumed that as the landfill was filled over time, the landfill would expand the GCCS into new areas of waste placement in time intervals that coincide with the expansion lag time specified in each option.

To determine when controls may be capped or removed, and to calculate the amount of landfill gas, NMOC, and methane collected under each option, the model uses L

0,

k, and NMOC values from AP-42 instead of the Tier 1 default values. To determine when control systems may be removed, subpart WWW requires landfills to conduct actual measurements of the collected gas flow rate and NMOC concentration. Because the AP-42 default values are more representative of actual emissions from landfills than Tier 1 values, they are more useful for predicting when a landfill would be able to remove its control system. For the same reason, AP-42 values were used to determine actual annual emissions reductions achieved by control systems.

To estimate the costs of each regulatory option, the EPA incorporated the estimated landfill gas recovery rates from the first-order decay equation and an estimated well field acreage into a set of cost equations based on EPA's Landfill Gas Energy Cost Model (LFGcost), version 2.3, which was developed by EPA's LMOP. (LFGcost estimates gas collection, flare and energy recovery system capital, operating, and maintenance costs.) The EPA also collected data on monitoring and testing costs such as initial performance tests, subpart WWW Tier 1 and Tier 2 calculations, and quarterly surface monitoring that were not provided in the LFGcost model.

The capital costs are all presented in year 2012 dollars and annualized using an interest rate of 7 percent over the lifetime of the equipment (typically 15 years), or in the case of drill mobilization costs, the length of time between each wellfield expansion. These annualized capital costs were added to the annual operating and maintenance costs estimated by LFGcost. The annualized cost includes capital requirements related to the purchase, installation, operation and maintenance of GCCS, and costs related to testing and monitoring requirements.

For certain landfills that were expected to generate revenue by using the LFG for energy, the EPA also estimated LFG energy recovery rates and associated costs to install and operate the energy recovery equipment as well as the revenue streams from the recovered energy. These revenues were subtracted from the annualized capital and operating and maintenance costs at each landfill in order to obtain a net cost estimate for each option in each year. The emission reduction and cost and revenue equations and assumptions are detailed in the docketed memorandum, “Methodology for Estimating Cost and Emission Impacts of MSW Landfills Regulations. 2014.”

Often the EPA examines the impacts of NSPS at 5 years after rule implementation; however, the EPA selected 10 years for this landfills NSPS review, 2023. Due to the emission characteristics of new landfills that begin to accept waste in 2014 or after and the applicability provisions of the NSPS, 5 years would not provide a representative population of landfills for evaluating alternative standards, and in fact none of the modeled landfills would be expected to have installed controls by year five. Landfills do not become subject to the control requirements of the NSPS on the date that they begin operation. Instead, landfills exceeding the design capacity threshold become subject to control requirements 30 months after the emissions exceed the NMOC emission threshold. It may take well over 5 years for a newly constructed landfill to exceed the NMOC threshold, depending on the rate of waste acceptance and other site-specific factors. Therefore, evaluating the impacts of the rule at 5 years would significantly underestimate the impacts that subpart XXX may have on affected facilities.

The EPA recognizes that landfills have a unique emissions and emission control timeline over their lifetime, compared to other stationary sources of emissions. The quantity of emission reductions achieved and the costs to achieve those reductions will vary depending on where each landfill is in its lifecycle. By year 10 (year 2023), landfills in this analysis are further along in their lifecycle than they would be at year five and over half of the modeled landfills have installed controls, incurred costs, and achieved emission reductions under several options the EPA considered in its review of the NSPS.

C. What control options did the EPA consider?

When determining which control options would represent BSER, the EPA ran many permutations of various control options. Some options adjusted a single threshold in isolation; for example, reducing the NMOC emission threshold while keeping the design capacity threshold constant, or conversely, reducing the design capacity threshold while keeping the NMOC emission threshold constant. Other options adjusted multiple control parameters simultaneously, taking into account the relationship between the parameters. For example, recognizing that NMOC emissions are a function of waste-in-place, some options that significantly reduced the NMOC emission threshold also reduced the design capacity thresholds to avoid situations where the NMOC emission threshold would be exceeded long before the design capacity threshold. Other options increased the design capacity threshold while reducing the NMOC emission threshold by relatively small increments in order to minimize the reporting-only burden that would be imposed on landfills that had exceeded the design capacity threshold, but not the NMOC emission threshold, and would therefore be reporting, but not controlling.

In addition to adjusting applicability and emission control thresholds, other model runs varied the initial and/or expansion lag times. These variations estimated the impacts of requiring landfill owners or operators to install gas collection systems more quickly after crossing each applicable NMOC emission threshold. Specifically, some model runs assessed the impacts of reducing the initial lag time from 30 months (modeled as 3 years for the purpose of this analysis, as discussed in the docketed memorandum “Methodology for Estimating Cost and Emission Impacts of MSW Landfills Regulations. 2014”) to 2 years. Model runs varying the expansion lag time were also run. For expansion lag times, subpart WWW allows 2 years after initial waste placement in closed areas and 5 years after initial waste placement in active areas of the landfill. As a result, the actual expansion lag time varies by landfill depending on how quickly expansion areas are filled and closed. Modern large landfill designs tend to expand the collection system 5 years after initial waste placement in active areas of the landfill. Based on input received during public outreach, most modern large landfills do not reach final grade within 2 years and a majority of landfills are complying with the 5 year provision. Therefore, a 4-year expansion lag time was assumed to represent the baseline, as discussed in more detail in the docketed memorandum “Methodology for Estimating Cost and Emission Impacts of MSW Landfills Regulations. 2014.” A shorter expansion lag time of 2 years after initial waste placement was examined as an alternative regulatory option. Some model runs evaluated the impacts of reducing both the initial and expansion lag times in parallel and other model runs evaluated the impacts of reduced emission and/or design capacity thresholds in conjunction with reduced initial and/or expansion lag times.

Preliminary results of the model runs showed that the current set of design capacity and NMOC emission threshold parameters in subpart WWW was the most cost effective option in year 2023. Options that reduced the NMOC emission threshold slightly, either in isolation or in conjunction with a reduction in the design capacity threshold had only a slightly higher cost effectiveness than the baseline. See the docketed memorandum “Cost and Emissions Impacts Resulting from the Landfills NSPS Review. 2014” and the docketed item “Modeling Database Containing Inputs and Results of Proposed Revisions to MSW Landfill NSPS. 2014.” Options that reduced the initial and/or expansion lag times to 2 years were typically less cost effective than the options that reduced the NMOC emission threshold.

Based on the results of the preliminary analysis, the EPA presented different model runs during Federalism consultations and small entity outreach that represented the range of variation in both the threshold and lag time parameters. For the options presented, Small entity representatives (SERs) and Federalism consultation participants provided feedback to the EPA, which included implementation concerns with varying certain parameters as part of this NSPS review, as discussed in the following section. The EPA took these concerns into consideration when developing the set of proposed options in this action.

D. What are the implementation concerns with changing the design capacity criteria?

Options that increase the design capacity threshold provide some opportunities for reduced reporting burden; however, these options also introduce the potential to miss emission reduction opportunities at certain landfills that exceed the NMOC

emission thresholds but do not meet the design capacity thresholds. Further, installation of GCCS at landfills with design capacities between 2.5 and 3.0 million Mg are well demonstrated. According to the LMOP database, there are more than 50 landfills out of 70 in this size range that have installed GCCS.

Options that reduce the design capacity threshold without also lowering the NMOC emission threshold would create additional reporting and permitting burden without any additional environmental benefit. These types of options would not change the number of landfills required to control emissions, but they would increase the number of landfills required to obtain an operating permit and also increase the number of landfills required to complete Tier 1 or Tier 2 emission calculations and reports.

When the EPA promulgated the 2.5 million Mg design capacity threshold in 1996, we considered the impact on small entities based on public comment (61 FR 9910). Today, small entities still tend to own smaller sized landfills, whereas larger entities tend to own larger regional landfills. Approximately 10 percent of the landfills subject to subpart WWW or the MSW landfills state or federal plan implementing subpart Cc are owned by small entities. Further, the cost burden for installing a collection and control system is more significant for small landfills, which are more often owned by small entities, than larger landfills. Certain costs to construct the gas collection system (e.g., flat fees for drill rig mobilization, and monitoring and construction costs) remain relatively constant regardless of the size of the landfill.

For these reasons, the EPA is not proposing any changes to the current design capacity threshold of 2.5 million Mg and 2.5 million m

3

.

E. What are the implementation concerns with reducing the NMOC threshold?

The EPA recognizes that NMOC emissions are site specific, varying widely from landfill to landfill and understands that a majority of landfills currently affected by subpart WWW conduct Tier 2 testing in order to refine their NMOC emission estimates before installing a GCCS.

Lowering the NMOC emission threshold would result in earlier GCCS installations, 13 percent more emission reductions, and a dollar-per-Mg cost to control NMOC that is higher than the baseline ($6,000/Mg NMOC vs. $4,400/Mg NMOC). Despite these higher costs, the EPA also recognizes the value of reducing methane emissions ($1.50/Mg CO

2

e vs. $1.10/Mg CO

2

e at baseline) that are associated with a lower NMOC emission threshold, as discussed in sections III and VI.B of this preamble. Based on these considerations, among others, the EPA is proposing to reduce the NMOC emission threshold from 50 Mg/yr to 40 Mg/yr. See section VI.B of this preamble for more details.

F. What are the implementation concerns with shortening the initial or expansion lag times?

The emission reductions achieved by reducing the initial or expansion lag time are affected by the size of the landfill, waste placement patterns, and annual acceptance rates. For example, the size of the landfill and the filling cycle affects how much and when emission reductions would be achieved. Based on comments received from SERs and Federalism consultation participants, modern landfill designs typically do not reach final grade before 7 years. Because the landfills NSPS allows two options for expanding the GCCS (2 years after initial waste placement in closed areas and 5 years after initial waste placement in active areas), any reduction to the 2 year lag time for closed areas would not likely achieve any actual additional reductions from these larger landfills because the majority of landfills are complying with the 5-year allowance period instead of the 2-year allowance period. Modifying the 5-year provision may also have a limited actual impact on emission reductions. Many landfills in wet climates install wells ahead of the 5-year schedule for odor or energy recovery purposes. When examining the effects of shortening the lag times, the emission reductions vary over the time period considered. To visually observe how reducing the lag times affects emissions and reductions over the 10-year period following proposal, see the charts comparing emissions from reduced lag times in the docketed memorandum, “Cost and Emissions Impacts Resulting from the Landfills NSPS Review. 2014.”

When isolating the timeframe for initial GCCS installation from the other control criteria, modeling showed that the reductions in year 2023 are lower than those estimated to be achieved under the current baseline. Although the initial GCCS would be installed earlier, for example in year 2020, it would also be designed slightly smaller (i.e., a smaller number of wells) than a GCCS installed in a later year. By 2023, the system would not have been expanded yet, thus, the total amount of emission reductions achieved in 2023 will be less than the baseline until the system is expanded in 2024.

Reducing the expansion lag time would achieve a short period of modeled reductions during every expansion cycle because the GCCS would be expanded one year earlier. Emission reductions in year 2023 would be approximately 27 percent higher than an option that did not shorten the expansion lag time. However, when considered over a 10-year period, the additional emission reduction would be approximately 8 percent.

Small entity representatives and Federalism consultation participants expressed concern about the potential shortening of lag times. For details, refer to the docketed report “Summary of Small Entity Outreach. 2014.”

According to the commenters, reduced lag times would result in the installation of more GCCS equipment in active fill areas. Wells located in these areas are more frequently damaged as a result of daily filling operations and the movement of equipment. Damaged wells must be repaired with well extensions and/or redrilling of wells. In addition, waste in active fill areas undergoes significant settlement. This settlement affects the alignment of gas header equipment, requiring more frequent repairs, troubleshooting, and replacement of equipment. These repairs can add a significant cost to the construction and operation of a GCCS that is not currently accounted for in the LFGcost estimates and also increase the amount of system downtime.

In addition to the implementation concerns, reducing the lag times would require more frequent mobilization of drill rig equipment, purchase of GCCS infrastructure, and system repairs, which could lead to higher costs. In year 2023, the dollar-per-Mg cost to reduce the initial and/or expansion lag times in conjunction with reducing the NMOC threshold are higher than the options that do not adjust the lag times ($6,900 to $11,300/Mg NMOC vs. $6,000/Mg NMOC). This higher cost is due in part to the timing of the first round of wellfield expansions at these new landfills, many of which were modeled to expand their systems in 2023, and thus incurring additional costs in that year to operate both the initial GCCS and the first set of expansion wells.

Small entity representatives and Federalism consultation participants raised several practical concerns with reducing the expansion lag time. Reducing the expansion lag time would result in more wells located in active fill areas because more of the face of the landfill is active after only 2 years of waste acceptance and the landfill owner

or operator must add wells into these active areas sooner.

In addition, active fill areas are still in the aerobic phase of waste decomposition. Installing wells in areas with high oxygen levels increases the chance of subsurface fires. It also leads to more frequent exceedances of the current wellhead monitoring standards for oxygen. In these cases the landfill owner or operator would also be unlikely to request a higher operating value for oxygen because they would have difficulty meeting the two criteria in proposed 40 CFR 60.763(c) for a higher operating value demonstration: A higher operating value must not cause fires and must not significantly inhibit anaerobic decomposition by killing methanogens. Neither of these criteria would apply to wells located in active fill areas.

Horizontal LFG collection wells may provide some relief to these implementation concerns that were raised by the SERs, while also allowing for the wells to be installed more quickly after the waste is placed in the landfill. These types of wells consist of perforated pipe in gravel-filled trenches constructed within the waste mass as an active area is filled. The wellheads are installed remotely outside of the active fill area to allow landfill owners/operators to monitor the wells. Although the horizontal collection infrastructure is installed as the waste is placed in the fill area, the collectors are not brought online under an active vacuum until a sufficient refuse layer has been placed on top of the collectors. This time period is necessary in order to prevent air infiltration in the landfill. However, this time period is often shorter than the timeframe needed to install vertical wells, and can be as short as a few months after refuse is buried.

20

20

Barlaz et al., Controls on Landfill Gas Collection Efficiency: Instantaneous and Lifetime Performance 59 J. Air & Waste Mgmt. Ass'n 1399, 1402-03 (Dec. 2009).

The EPA is aware of several horizontal collector installations, including several landfills in California

21

and 18 different landfills that reported using horizontal collectors in the voluntary data collection effort for this rulemaking (see “Summary of Landfill Dataset Used in the Cost and Emission Reduction Analysis of Landfills Regulations. 2014”).

21

SCS Engineers, Technology and Management Options for Reducing Greenhouse Gas Emissions. Prepared for California Integrated Waste Management Board.

The shorter length of time associated with bringing horizontal collectors online can be especially important at landfills employing liquids recirculation techniques or located in wetter climates, given the higher LFG generation rates at those sites (see section V.G of this preamble). Bringing these collectors online more quickly and more proactively addresses odor concerns at landfills. These systems are also useful in landfills that practice “over-filling,” where new waste is placed on top of a section of the landfill that was capped temporarily. SERs did express some implementation concerns with horizontal collectors, indicating that these systems have a shorter lifetime than vertical wells and require more frequent replacement.

For the reasons presented in this section, the EPA is not proposing to shorten the initial or expansion lag times from the lag times codified in subpart WWW. However, the EPA requests comment on the feasibility and potential benefits of reducing either or both of the lag times. Specifically, the EPA requests comment on the practicality, cost, and emission reduction implications of installing or expanding the wellfield on active areas in a shorter timeframe. The EPA believes that this may be appropriate since horizontal collector systems have been installed at several landfills that were not in operation when the NSPS was originally promulgated in 1996. The EPA also requests data and/or comment on the potential emission reductions and corresponding costs that could result from reduced lag times. The EPA also notes that the cost analysis presented in section X of this preamble is based on vertical wells and the EPA is interested in any comments and data that address any differential in costs between these two types of systems.

G. Request for Comment on BSER

The EPA is requesting comment on several items regarding BSER. EPA is requesting comment on the proposed design and operational standards for new sources that EPA believes are necessary to ensure a GCCS is well designed and well operated. The EPA is requesting comment on additional emission control technologies that are in place at landfills—other than a GCCS as described here—that could be considered BSER. We request descriptions of such systems, an indication of their current use, data demonstrating emission reductions, and corresponding costs of such systems. The EPA is also requesting comment on whether a well designed and well operated GCCS in conjunction with any of the technologies or practices discussed in section V.A of this preamble should be considered to be BSER.

The EPA is also taking comment on whether it should consider reducing the design capacity threshold or initial lag times for landfills that are located in a wet climate or that recirculate leachate or add other liquids to the landfills to accelerate waste decomposition. Wetter wastes decompose more quickly than drier wastes and as a result generate more landfill gas in the short term. Therefore, it may be appropriate to require these landfills to install the gas collection system sooner, which SERs indicated is already occurring in practice for landfills in wetter climates. Similarly, smaller landfills in wetter climates, or those employing leachate recirculation, may also generate earlier spikes in landfill gas emissions that could exceed the NMOC threshold. Although these landfills are exempt from proposed subpart XXX under the design capacity threshold of 2.5 million Mg and 2.5 million cubic meters, if a smaller design capacity threshold were adopted for these wet landfills, more emission reductions may be achieved.

If a separate set of thresholds and/or lag times were to apply to these wet landfills, the EPA requests comment on how a wet landfill might be defined. For example, a wet landfill could be defined as a landfill that has precipitation of greater than 25 inches per year and/or recirculates leachate (or other liquids).

VI. Rationale for the Proposed Changes Based on Review of the NSPS

To determine which option to propose, the EPA considered the emission reductions that are expected to be achieved under the criteria in the baseline (subpart WWW), as well as emission reductions that would be achieved under several control options more stringent than the baseline.

A. What are the environmental impacts and costs associated with the baseline?

In this analysis, the baseline contains the same gas collection and control requirements and thresholds (2.5 million Mg or 2.5 million cubic meters and 50 Mg NMOC per year) that are in subpart WWW. For the baseline, the initial lag time is 30 months; and the expansion lag time is 2 years after initial waste placement in cells that are closed or at final grade or 5 years after initial waste placement in active areas of the landfill. These parameters are described in detail in section V of this preamble.

Table 2 of this preamble summarizes the impacts of the baseline for year 2023. The table includes emission reductions for NMOC, methane, and carbon dioxide equivalent (CO

2

e) and corresponding annualized net costs based on the annualized control, testing,

and monitoring costs, and annual revenues from energy recovery (when applicable), as discussed in section V.B of this preamble.

Table 2—Baseline Emission Reductions and Costs in 2023

Number of

landfills

affected

Number of

landfills

controlling

Number of

landfills

reporting

but not

controlling

Annual

net cost

($2012)

a

Annual

NMOC

reductions

(Mg/yr)

Annual

methane

reductions

(Mg/yr)

Annual CO

2

e

reductions

(Mg/yr)

NMOC cost

effectiveness

($/Mg)

Methane cost

effectiveness

($/Mg)

CO

2

e cost

effectiveness

($/Mg)

17

8

9

2,708,000

610

94,800

2,371,000

4,400

29

1.1

a

The annualized net cost ($2,708,000) is the difference between the average annualized revenue ($21,315,300) and the sum of annualized control cost ($23,956,900) and the average annualized testing and monitoring costs ($66,400).

The baseline is estimated to require control at eight landfills in 2023, and achieve reductions of 610 Mg/yr NMOC, 94,800 Mg/yr methane (2,371,000 Mg/yr CO

2

e). The annualized net cost is $2.7 million. The cost effectiveness of the baseline is estimated to be $4,400 per Mg NMOC, and $29 per Mg methane ($1.10 per Mg CO

2

e) if all of the control cost were attributed to each pollutant separately.

In this analysis, the EPA projects 21 new landfills would commence construction, reconstruction, or modification between 2014 and 2018. The basis of this projection is discussed in detail in the docketed memorandum “Summary of Landfill Dataset Used in the Cost and Emission Reduction Analysis of Landfills Regulations. 2014.” These 21 landfills are projected to emit, 1,040 Mg/yr of NMOC and 161,600 Mg/yr of methane in 2023 if the landfills had no emission controls in place. However, the baseline is modeled to require 38 percent (8/21) of these projected landfills to install emission controls by at least year 2023. In terms of emissions, the baseline is expected to achieve 59 percent reduction in estimated emissions from these landfills in 2023. Further, the eight landfills installing controls under the baseline represent 77 percent of the estimated total waste-in-place in 2023 from all 21 of the projected landfills.

The baseline allows landfills to remove the GCCS only after the following criteria are met (1) the landfill is closed, (2) the landfill has had the GCCS in operation for at least 15 years, and (3) three successive tests for NMOC emissions are below the NMOC emission threshold of 50 Mg/yr. Until the GCCS is removed, the landfill must continue to operate the system in accordance with 40 CFR 60.763, which includes wellhead monitoring and surface emissions monitoring to detect and correct for any emission exceedances.

B. How did the EPA determine which control option to propose?

When determining which control options would represent BSER, the EPA considered several factors: The implementation concerns identified in section V of this preamble; and the incremental emission reductions, cost, and co-benefits that would be achieved beyond the baseline.

The EPA compared the annualized net cost and emission impacts in 2023 of the various regulatory options to the annualized net costs and emission impacts in 2023 of the baseline. The EPA analyzed numerous iterations of alternate control and reporting thresholds and presented potential control options to SERs and Federalism consultation participants, as described in section V of this preamble. After considering feedback from the SERs and Federalism consultation participants, the EPA selected for consideration three regulatory alternatives as presented in Table 3 of this preamble. Table 3 of this preamble summarizes the incremental impacts of each control option, when compared to the baseline. The table shows the emission reductions and corresponding annualized net costs for NMOC and methane in 2023.

Table 3—Emission Reductions and Costs for Control Options in Year 2023

Control parameters

Number of landfills

affected

a

Number of landfills

controlling

a

Annual net cost

(2012$)

Annual NMOC

reductions

(Mg/yr)

Annual

methane

reductions

(Mg/yr)

Annual

methane

reductions

(Mg CO

2

e/yr)

NMOC cost

effectiveness

($/Mg)

Methane cost effectiveness

($/Mg)

Methane cost effectiveness *

($/Mg CO

2

e)

Baseline = 2.5 million Mg and m

3

, design capacity and 50 Mg/yr NMOC

Baseline (2.5 design capacity/50 Mg/yr NMOC)

17

8

2,708,000

610

94,800

2,371,000

4,400

29

1.1

Incremental values versus the Baseline

Option (3.0 design capacity/40 Mg/yr NMOC

0

3

471,000

79

12,300

307,600

6,000

38

1.5

Option (2.5 design capacity/40 Mg/yr NMOC

0

3

471,000

79

12,300

307,600

6,000

38

1.5

Option (2.0 design capacity/40 Mg/yr NMOC

1

3

472,700

79

12,300

307,600

6,000

38

1.5

a

Landfills are affected by the landfills NSPS based on design capacity. Once affected, they calculate and report emissions until they exceed the NMOC threshold, which triggers control requirements.

Baseline.

The baseline affects 17 new landfills, meaning that 17 landfills meet the design capacity thresholds and would have to report their emissions during this period. Eight of these landfills would have controls in place in

year 2023. The baseline values are compared to landfills' emissions assuming that no GCCS are installed. This comparison to a no-control scenario may overestimate both the costs and emissions reduction resulting from implementation of subpart XXX due to other regulatory or voluntary reasons for installing GCCS, as discussed below.

The EPA is aware that some state or local ordinances require landfill gas combustion for odor, safety, or methane control reasons. For example, methane regulations in California

22

require GCCS to be installed at all landfills accepting waste after January 1, 1977, having at least 450,000 tons of waste-in-place, and having a gas heat input capacity threshold of 3.0 MMBtu/hr or greater to install GCCS. The emission reductions from these programs could not be quantified for the projected set of model landfills because the EPA cannot reliably estimate where these future landfills will be installed.

22

California Code of Regulations, title 17, subchapter 10, article 4, subarticle 6, sections 95460 to 95476, Methane Emissions from Municipal Solid Waste Landfills.

Finally, based on data from LMOP, the EPA is also aware of approximately 500 landfills that have voluntarily installed a gas collection system that would not otherwise be required under federal NSPS or emission guideline regulations (see section V.A of this preamble for details). These systems may have been installed to recover energy and generate revenue, including sale of electricity or landfill gas as well as to create carbon credits. However, because it is not known how many projected new landfills will voluntarily collect and combust their gas in the absence of NSPS regulation, the reductions associated with voluntary gas collection system installations were not considered when establishing the reductions associated with the baseline.

Regulatory options.

The EPA considered three regulatory options more stringent than the baseline, as presented in Table 3 of this preamble. Based on the characteristics of the projected landfills, all three of the more stringent options would require a total of 11 landfills to install controls by 2023. Thus, 11 landfills would incur costs and achieve emission reductions in 2023 under all of the more stringent options, compared with eight landfills under the baseline.

Although the overall difference in the number of landfills requiring control in 2023 under the more stringent options is only three landfills, it is important to note that each of these options would require controls to be installed earlier than the baseline, because lower NMOC emission thresholds would subject landfills to the control requirements at an earlier date.

Table 4 presents the number of landfills with control systems installed, by year, for the baseline and options considered in this analysis. Due to the 30-month initial lag time period, no controls are anticipated to be installed prior to 2020 under any of the options under consideration.

Table 4—Total Number of New Landfills Projected To Control Landfill Gas Emissions in Each Year of the 10-Year Period, by Option

Control parameters

Number of landfills with

control systems installed

2014-2019

2020

2021

2022

2023

Baseline 2.5/50

0

0

6

7

8

Option 3.0/40

0

3

6

7

11

Option 2.5/40

0

3

6

7

11

Option 2.0/40

0

3

6

7

11

Emission reductions.

Under all three of the options considered, three additional landfills would be required to install controls in 2023 compared to the baseline. The reductions achieved under these three options are the same because each option has the same NMOC threshold trigger of 40 Mg/yr. The corresponding emission reductions in 2023 would be an additional 79 Mg/year NMOC, 12,300 Mg/year methane (307,600 Mg/year CO

2

e) compared to the baseline. The wide range in magnitude of emission reductions among pollutants is due to the composition of landfill gas: NMOC represents less than 1 percent of landfill gas, while methane represents approximately 50 percent. CO

2

e is an expression of methane in terms of the carbon dioxide equivalents, given the methane global warming potential (GWP) of 25.

23

Each of these options represents approximately a 13 percent reduction beyond the baseline.

23

IPCC Fourth Assessment Report (AR4), 2007. Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, Pachauri, R.K and Reisinger, A. (eds.)]. IPCC, Geneva, Switzerland, 104 pp.

Cost.

Under both options 2.5/40 and 3.0/40, the incremental annual cost would be $471,000. The cost is identical for these two options because all of the projected new landfills that exceed the NMOC thresholds and install controls by 2023 have a design capacity greater than 3.0 million Mg. Based on the characteristics of recently constructed landfills, it is likely that most new landfills will be larger sites. The incremental annual cost of option 2.0/40 is $2,700 higher, at $472,700 due to additional reporting costs for one landfill that is projected to exceed the lowered design capacity threshold but not the NMOC threshold. All of these options represent approximately 17 percent in additional costs beyond the baseline.

In terms of cost effectiveness, the overall dollar-per-Mg cost for NMOC reductions is $4,400 per Mg NMOC under the baseline in Table 3 of this preamble. Note the cost of controlling methane is significantly lower than for NMOC because methane constitutes approximately 50 percent of landfill gas, while NMOC represents less than 1 percent of landfill gas. The incremental dollar-per-Mg cost for NMOC reductions is $6,000 per Mg NMOC under all of the other options. For option 2.0/40, however, there are additional reporting requirements for one landfill affected by this option that would result in a marginally higher actual cost compared with the option 2.5/40. Therefore, we are not proposing option 2.0/40. Other than the added reporting costs, the emission reductions and control costs are identical for options 2.5/40 and 3.0/40. For the reasons stated in section V.D of this preamble (potential to miss reductions at landfills that exceed the NMOC emission thresholds but do not

meet the design capacity thresholds and application of GCCS at landfills with design capacities between 2.5 and 3.0 million Mg is well demonstrated), alternative option 3.0/40 is also not being proposed.

Proposed option 2.5/40.

Based on the emission reduction and cost discussions above and consistent with the President's Methane Strategy as discussed in section III of this preamble, the EPA is proposing to reduce the NMOC threshold to 40 Mg/yr. Lowering the NMOC threshold would result in earlier GCCS installations and additional NMOC and methane reductions compared to the baseline, as shown in Table 3 of this preamble. This lowered threshold achieves reductions without adjusting the initial and expansion lag times and incurring the associated costs and implementation concerns.

Reducing the NMOC threshold from the baseline-level of 50 Mg/yr to 40 Mg/yr would affect only three more landfills in 2023 but would achieve an estimated 13 percent additional reduction in emissions of NMOC and methane compared to the baseline. Further, this proposal would maintain the same control device removal criteria as the baseline except that the controls would have to stay on until three successive tests for NMOC emissions were below the NMOC emission threshold of 40 Mg/yr instead of 50 Mg/yr. Depending on the waste-in-place of the landfill at closure and other site-specific factors (e.g., waste composition, climate), it may take more than 30 years after closure for a large modern landfill to emit less than the NMOC emission threshold, and in turn qualify for capping or removing the GCCS. Although the emission reductions associated with these later years in the landfills' lifetimes are not incorporated in the environmental and economic impacts of the baseline and options under consideration, the lower threshold associated with this proposal would require controls to be installed for a slightly longer period than the baseline.

Although some commenters have expressed concerns about the quantity of emissions after landfills have closed and the GCCS has ceased to operate, the analysis the EPA conducted demonstrates that GCCS would be installed for a significant period after landfill closure that is commensurate with the size and corresponding emissions profile of each affected landfill. For these reasons, the EPA is proposing that emissions must be below an emissions threshold of 40 Mg/yr as one of the three criteria for determining when a GCCS may be capped or removed. The EPA is also requesting comment on whether these three criteria are appropriate, and if alternative criteria such as consecutive quarterly measurements below a surface emission threshold should also be considered. RCRA, specifically subpart F of Part 258, also requires supplemental basic post-closure care to maintain cover integrity.

Reducing the NMOC threshold also recognizes the opportunity to build upon progress to date and achieve even more reductions of landfill gas and its components, consistent with the President's Methane Strategy as discussed in section III of this preamble. Landfill gas generated from established waste (waste that has been in place for at least a year) is typically composed of roughly 50 percent methane and 50 percent carbon dioxide by volume, with less than 1 percent NMOC. Because the components of landfill gas are associated with substantial health, welfare, and climate effects, additional reductions of landfill gas would improve air quality and reduce health and welfare effects associated with exposure to landfill gas emissions. Note that in 2012, landfills continued to be the third largest source of human-related methane emissions in the United States, representing 18.1 percent of total methane emissions.

24

Methane emissions represent 8.7 percent of all GHG emissions (in CO

2

e) in the United States.

Alternative option 2.0/34.

Consistent with the President's Methane Strategy and the potential to achieve a near-term beneficial impact in mitigating global climate change (see section III of this preamble), the EPA considered even more stringent alternatives in its analysis of control options that may achieve additional reductions of methane and NMOC. For example, reducing the NMOC threshold below 40 Mg/yr in conjunction with reducing the design capacity to below 2.5 million Mg or 2.5 million cubic meters, an alternative option 2.0/34 would require controls at 11 landfills by 2023, which is the same number of landfills required to control under this proposal. However, under this more stringent option, four of the 11 landfills would install controls one year earlier. The extent of the emission reductions for this option depends on the time period considered. For example, in year 2023, emission reductions would not be any greater than the proposal. However, when averaged over the 10-year period (2014-2023), this more stringent option would achieve additional NMOC and methane reductions compared with the proposal. Refer to the Environmental Impacts Analysis,

25

and the docketed memoranda “Cost and Emissions Impacts Resulting from the Landfills NSPS Review. 2014” for details on the estimated reductions. Additional emission reductions would be expected to be achieved over the lifetime of the landfills subject to subpart XXX because the lower NMOC threshold would require earlier installation of controls and also require the controls to remain installed for a longer period. The annualized cost to implement alternative option 2.0/34 would be higher than the proposal. The EPA did not analyze an option that reduced the NMOC threshold below 40 Mg/year without also reducing the design capacity threshold. In light of these additional reductions, as well as the additional costs to affected entities, the EPA is soliciting comment on whether an NMOC threshold below 40 Mg/yr in conjunction with a reduced design capacity threshold should be considered for new landfills subject to subpart XXX.

25

Municipal Solid Waste Landfills, Economic Impact Analysis for the Proposed New Subpart to the New Source Performance Standards.

VII. Summary of Clarifications and Resolutions That Are the Result of Implementation Activity

The EPA proposed amendments to the landfills NSPS (40 CFR part 60, subpart WWW) on May 23, 2002 (67 FR 36475) to address implementation issues. Consideration of public comments received and additional implementation activity led to the proposal of further clarifications on implementing the landfills regulations on September 8, 2006. After considering public comments received on the September 8, 2006 amendments and additional implementation activity, we are proposing resolutions and clarifications of the issues specifically identified below under new subpart XXX. The EPA plans to address amendments and clarifications resulting from implementation activities as they apply to subparts Cc and WWW in a separate document. The EPA will also address any potential changes to subparts Cc and WWW in a separate document. Thus EPA is not taking final action on either the May 23, 2002 or the September 8, 2006 proposed rules at this time. In addition to the specifically identified resolutions and clarifications associated with the May 23, 2002 and September 8, 2006 proposed rules, we are proposing a number of provisions in subpart XXX that are intended to address other implementation issues

that have arisen in the context of subpart WWW.

2002 Proposed amendments.

On May 23, 2002 (67 FR 36475), the EPA proposed several amendments to subpart WWW, including clarifying what constitutes treated landfill gas by adding a definition of treatment system that specified that the system must filter, de-water, and compress landfill gas.

2006 Proposed amendments.

Public comments on the May 23, 2002 amendments created new questions and caused the EPA to reconsider the approach we had taken on several proposed amendments, including our approach to clarifying what constitutes treated landfill gas. Specifically, we proposed refined definitions of “treated landfill gas” and “treatment system” by adding specific numerical values for filtration and de-watering to provide long-term protection of the combustion equipment, which would also support good combustion. The September 8, 2006 amendments also proposed to clarify the monitoring requirements for treatment systems.

The following resolutions and clarifications apply to proposed subpart XXX.

A. Definitions for Treated Landfill Gas and Treatment System and Treatment System Monitoring

Subpart XXX contains requirements for landfill gas treatment that are consistent with the September 8, 2006 proposed amendments, except that the treatment definition would require the water dew point of landfill gas to be reduced to at least 45 °F, rather than lowered by at least 20 °F. We also propose to specify a location for the temperature monitoring device that would demonstrate continuous compliance with the 45 °F requirement. The measurement device would be located at (or immediately after) the coalescing filter or other direct contact moisture removal device that follows the chiller and removes the condensed moisture. If a landfill owner/operator uses de-watering equipment that is not based on cooling the gas, such as a desiccant system, the landfill owner/operator would monitor dew point instead of temperature. For particulate matter filtration, we propose to retain the requirement for a filter system to have an absolute rating no greater than 10 microns.

We also propose to clarify monitoring, recordkeeping, and reporting requirements for treatment systems. To ensure that treatment systems are operating properly to achieve the filtration and de-watering levels specified in the revised proposed treatment system definition, owners/operators would install equipment to continuously monitor pressure drop across a filter, temperature for a chiller-based de-watering system, and dew point for a non-chiller-based de-watering system. Owners/operators would record 24-hour block averages. Owners/operators may use other site-specific monitoring parameters if they demonstrate that such parameters would effectively monitor filtration or de-watering system performance. For other site-specific monitoring parameters, owners/operators must develop operating ranges for each monitored operating parameter based on manufacturer's recommendations or engineering analysis and submit those ranges, along with justification, for approval by the Administrator in an amended design plan. The proposed recordkeeping and reporting requirements for treatment systems are similar to those for control device temperature monitoring requirements already in the NSPS.

The EPA is considering and taking public comment on an alternative approach to defining landfill gas treatment and the corresponding monitoring requirements, as discussed in section IX.A of this preamble.

Uses of treated landfill gas.

Subpart WWW allows landfill owners or operators the option of achieving compliance by routing the collected gas to a treatment system “that processes the collected gas for subsequent sale or use.” We propose to include language in subpart XXX (40 CFR 60.762(b)(2)(iii)(C)) to clarify that the use of treated landfill gas is not limited to use as a fuel for a stationary combustion device, as some people have previously interpreted this compliance option, but also includes other uses such as the production of vehicle fuel, production of high-Btu gas for pipeline injection, or use as a raw material in a chemical manufacturing process.

B. Startup, Shutdown and Malfunction Provisions

The general provisions in 40 CFR part 60 provide that emissions in excess of the level of the applicable emissions limit during periods of startup, shutdown and malfunction (SSM) shall not be considered a violation of the applicable emission limit

unless otherwise specified in the applicable standard

(see 40 CFR 60.8(c))(emphasis added). As reflected in the italicized language, an individual subpart can supersede this provision. In today's action, the EPA is proposing standards in subpart XXX that apply at all times, including periods of startup or shutdown, and periods of malfunction. In addition, to enable the EPA to determine the severity of an emissions exceedance for periods when the gas collection system or a control device is not operating, the EPA is proposing to add a recordkeeping and reporting requirement for landfill owners or operators to estimate emissions during such periods.

C. Closed Areas

To determine whether NMOC emissions from nonproductive areas of the landfill are less than 1 percent of the total landfill NMOC emissions (and hence controls are not required), subpart WWW relies on modeled (calculated) NMOC rates (see 40 CFR 60.759(a)(3)(ii)). To refine the measurements of these nonproductive areas, the EPA is proposing to allow owners or operators of landfills subject to subpart XXX to use measured or modeled flow of landfill gas to determine if an area is nonproductive. The EPA proposes that owners or operators of physically separated, closed areas of landfills subject to subpart XXX may use the procedures in proposed 40 CFR 60.764(b), which determine the flow rate of landfill gas using actual or modeled measurements, to determine NMOC emissions.

D. Surface Monitoring

Subpart WWW requires quarterly surface monitoring to demonstrate that the cover and gas collection system are working properly. The intent of the surface monitoring provision is to maintain a tight cover that minimizes landfill gas emissions through the landfill surface. In this proposal, we are reiterating the intent that landfills must monitor along a pattern that traverses the landfill at specified intervals and where visual observations indicate elevated concentrations of landfill gas, which includes all cover penetrations and openings within the area of the landfill where waste has been placed and a gas collection system is required. The EPA is also considering and taking public comment on revisions to the surface monitoring requirements, as discussed in section IX of this preamble.

E. Electronic Reporting

The EPA is proposing electronic reporting of required performance test reports, NMOC emission rate reports, and annual reports. We also propose that industry should be required to maintain only electronic copies of the records to satisfy federal recordkeeping requirements. The proposed electronic submission and storage procedures are

discussed in detail in section VIII.E of this preamble.

The proposal to submit performance test data electronically to the EPA applies only to those performance tests conducted using test methods that are supported by the Electronic Reporting Tool (ERT). At this time, most of the methods in the landfills NSPS are not supported by the ERT. Thus, electronic reporting of performance tests may not be required for some landfills initially, but will be required when applicable methods are added to the ERT. A listing of the pollutants and test methods supported by the ERT is available at:

http://www.epa.gov/ttn/chief/ert/index.html.

F. Wellhead Monitoring Requirements

Subpart WWW addresses operational standards for wellheads. Under 40 CFR 60.753(c), landfill owners/operators may request and demonstrate a higher operating temperature, nitrogen, or oxygen value at a particular well. The EPA is clarifying in this preamble the intent of the following requirement: “A higher operating value demonstration must be submitted to the Administrator for approval and must include supporting data demonstrating that the elevated parameter neither causes fires nor significantly inhibits anaerobic decomposition by killing methanogens.” The demonstration must meet

both

criteria; that is a higher operating value must not cause fires

and

must not significantly inhibit anaerobic decomposition by killing methanogens.

The EPA proposes to clarify in subpart XXX that any alternate operating value for temperature, nitrogen, or oxygen proposed by an owner or operator according to the proposed 40 CFR 60.763(c) must be submitted to the Administrator (i.e., the EPA Administrator or delegated authority) for approval. The request may be submitted separately from a design plan revision. However, the design plan would have to be updated on the schedule described in the next section.

The EPA is also considering and taking comment on the landfill wellhead monitoring requirements, as discussed in the section IX.B of this preamble.

G. Requirements for Updating the Design Plan

We propose adding three criteria for when an affected source must update its design plan and submit it to the Administrator under subpart XXX (40 CFR 60.767(h)). We propose requiring submittal of a revised design plan as follows: (1) Within 90 days of expanding operations to an area not covered by the previously approved design plan; (2) prior to installing or expanding the gas collection system in a manner other than described in a previously approved design plan; and (3) prior to implementing an alternative operating parameter value for temperature, nitrogen, or oxygen.

H. Submitting Corrective Action Timeline Requests

Subpart WWW outlines the timeline for correcting for air infiltration in the gas collection system within 15 days of any exceedance of temperature, nitrogen, or oxygen parameters. We propose clarifying this requirement in subpart XXX (40 CFR 60.765(a)(5)) to require the landfill to submit an alternative corrective action timeline request to the Administrator if the landfill cannot correct for air infiltration within 15 calendar days of the initial exceedance and the landfill is unable to (or does not plan to) expand the gas collection within 120 days of the initial exceedance.

I. Other Corrections and Clarifications

We propose to standardize the terms “control system” and “collection and control system” throughout proposed subpart XXX in order to use consistent terminology throughout the regulatory text. Subparts Cc and WWW include phrases such as “control or treatment system”; however, 40 CFR 60.752(b)(2)(iii) indicates that a treatment system described in 40 CFR 60.752(b)(2)(iii)(C) is considered to be a type of control system, and therefore the term “control system” is sufficient and more concise. Further, some other parts of subpart WWW refer to “collection and control device” or “control equipment”; however, the terms “device” and “equipment” are synonymous with the term “system” in the context of these rules and were replaced with “control system” or “control system equipment” in several places as appropriate, for consistency. Finally, many parts of subpart WWW inaccurately reference “control system” instead of “collection and control system” when referring back to paragraphs in 40 CFR 60.752(b). These corrections and clarifications appear in subpart XXX.

We also propose to make the following clarifications and corrections to subpart XXX, which are consistent with the May 23, 2002 and September 8, 2006 proposed amendments in subpart WWW.

Consistent with the May 23, 2002 and September 8, 2006 proposed amendments, we propose to include language in subpart XXX to exempt owners/operators of boilers and process heaters with design capacities of 44 megawatts or greater from the requirement to conduct an initial performance test (40 CFR 60.762(b)(2)(iii)(B)).

Consistent with the September 8, 2006 proposed amendments, we propose to remove the term “combustion” from the requirement to monitor temperature of enclosed combustors (40 CFR 60.768(b)(2)(i) and 40 CFR 60.768(c)(1)(i)).

Consistent with the September 8, 2006 proposed amendments, we propose to incorporate a corrected test method cross-reference in 40 CFR 60.765(c)(3) of subpart XXX necessitated by the reorganization of Method 21 in appendix A to 40 CFR part 60.

Consistent with the September 8, 2006 proposed amendments, we propose to amend the definition of “household waste” and add a definition of “segregated yard waste” in subpart XXX (40 CFR 60.761) to clarify our intent regarding the applicability of the landfills NSPS to landfills that do not accept household waste, but accept segregated yard waste.

We are clarifying that the definition of “Modification” in subpart XXX includes a change in mass or volume and we are requesting comment on the definition of modification as discussed in section VIII.I of this preamble.

VIII. Rationale for the Clarifications and Resolutions That Are the Result of Implementation Activity

A. Definitions for Treated Landfill Gas and Treatment System and Treatment System Monitoring

Landfill gas treatment.

In the May 23, 2002 proposed amendments, we proposed a definition for “treatment system” that would be used to determine if a facility qualifies for the treatment option provided in subpart WWW. The purpose of this definition was to provide consistency as to what qualifies as a treatment system and to reduce the burden on state and local agencies and EPA Regions currently performing case-by-case determinations related to the adequacy of treatment options being employed across the nation. The proposed definition of treatment system was “a system that filters, de-waters, and compresses landfill gas.”

Following the May 23, 2002 proposal of the treatment system definition, several commenters requested further clarification as to what levels of filtration and de-watering would be considered acceptable to meet the definition of treatment. Some

commenters requested that EPA allow owners/operators to treat their gas such that it would meet the end-use combustion equipment “manufacturer's requirements” for fuel quality. Other commenters requested that EPA develop specific particulate, moisture, and compression targets that demonstrate “treated landfill gas.”

We agreed with commenters that the definition of treatment system needed additional detail. We contacted manufacturers of combustion devices that are used to recover energy from landfill gas, and we obtained their written specifications and recommendations for fuel quality. As suggested by the commenters, we reviewed the available manufacturers' specifications for acceptable moisture and particulate levels. Because different manufacturers have different specifications, our proposed definition of “treatment system” did not refer directly to the manufacturers' requirements. Instead, we developed specific filtration and de-watering targets based on those requirements.

On September 8, 2006, we proposed levels of de-watering and filtration that were consistent with most manufacturers' specifications for landfill gas burned in energy recovery devices such as reciprocating engines, gas turbines, and boilers. We also proposed a supplemental definition of treatment system, as follows: “. . . a system that has an absolute filtration rating of 10 microns or less, lowers the water dew point of the landfill gas by at least 20 degrees Fahrenheit with a de-watering process, and compresses the landfill gas.” The term “absolute filtration rating” means the diameter of the largest hard spherical particle that would pass through the filter. These treatment levels would minimize degradation of the combustion device and promote proper destruction of NMOC.

Following the September 8, 2006 supplemental amendments, several commenters objected to the 20 °F dew point reduction requirement and the requirement to monitor temperature reduction across the moisture removal system. Commenters cited several reasons, including the following:

• In cold climates, it might not be feasible to meet the proposed definition because the gas can be cooled from wellhead to temperatures in the 40 °F-range simply because of ambient conditions, and lowering the temperature further is not feasible.

• Verifying inlet and outlet temperatures is difficult because they vary depending on the pressures in the system. Accounting for these conditions could require multiple points of measure plus use of an algorithm to determine the reduction.

• The proposed standard does not take into account water removal that may be occurring in other parts of the gas collection system, such as the header.

• The level of treatment needed depends on the type and design of the specific combustion equipment being used, so some commenters favored case-by-case determinations.

The EPA maintains the position that the intent of the treatment option is to require active lowering of the dew point consistent with the better available treatment systems, and that we did not intend knock-out pots (for example) to qualify. The numerical specifications ensure that the treated gas is suitable for use in a wide range of applications. They also allow uniform national application of the NSPS, provide certainty to the landfill industry and regulated agencies, and avoid case-by-case determinations that are likely to be complex, time-consuming, and yield inconsistent results.

However, the EPA agrees with the comments that the 2006 proposed 20 °F dew point reduction requirement contains some ambiguity. For example, is the 20 °F relative to the gas temperature at the wells, in the main header prior to compression, or just prior to the chiller? Does the gas need to be chilled 20 °F below atmospheric temperature, which could be impractical in cold climates? We also agree with the commenters that if the treatment system first compresses and then chills the gas, measuring the gas temperature before the compressor and after the chiller would not give an accurate indication of the dew point reduction due to the change in pressure, and algorithms would be required to calculate the reduction.

In light of these comments, we reviewed designs from manufacturers of gas treatment compression-dehydration skids for the landfill gas utilization industry to determine if the numerical moisture requirement could be expressed as an absolute dew point or temperature that could be measured at a single location, rather than requiring a 20 °F reduction. Such a requirement would eliminate ambiguity and make it easier for landfills and regulatory agencies to determine compliance. Manufacturers commonly compress the gas first and then cool the gas to reduce the dew point. Manufacturers commonly offer dew points of 38 to 45 °F. They also reheat the final dehydrated product prior to it leaving their treatment unit. Therefore, we propose a dew point reduction to 45 °F, rather than a reduction by 20 °F.

The EPA requests comments on all aspects of this proposed definition of landfill gas treatment.

Continuous monitoring.

To ensure continuous compliance with the treatment option, we are proposing similar monitoring requirements to the September 8, 2006 supplemental proposal, except that temperature or dew point is measured at a single location to determine that it has been reduced to 45 °F, rather than measuring it before and after the moisture removal device. Landfill owners/operators would install instrumentation to continuously monitor pressure drop across a filter, temperature for a chiller-based de-watering system, and dew point for a non-chiller-based de-watering system. These requirements would ensure that the treatment system is continuously operating in the manner in which it was designed to operate to achieve the specific filtration, de-watering, and compression targets that define a treatment system for the purposes of the landfills NSPS.

Continuous monitoring is appropriate for treatment systems because it ensures timely identification of sudden failures in equipment such as chillers and filters and ensures that treatment systems are operating properly to achieve the filtration and de-watering levels specified in the rule. Continuous monitoring is available for the selected treatment system operating parameters and is required to ensure continuous compliance.

For filtration systems, the pressure drop (24-hour average) across the filter would be continuously monitored and maintained above the minimum pressure drop established by engineering analysis or manufacturer's specifications. Alternatively, the owners/operators can request approval to monitor another parameter that indicates proper performance of the filtration system. Pressure drop was selected as a monitoring parameter because it is a good indicator of proper filter operation. A noticeable reduction in pressure drop across the filter indicates a breach of the filter material.

Continuous monitoring of temperature for a chiller-based de-watering system, dew point from a de-watering system that is not chiller-based, or another approved parameter that is indicative of proper performance of the de-watering system, would also be required. If the owner/operator requests to measure a parameter other than temperature or dew point, then the monitored parameter (24-hour average) would have to be kept within the operating range established by engineering analysis or manufacturer's

specifications. The owner or operator would submit the treatment system design and justification for the operating parameter ranges for approval by the Administrator in the design plan required by 40 CFR 60.752(b)(2) of subpart WWW.

For chiller-based de-watering systems, we selected temperature as a monitoring parameter because it indicates that the chiller is operating properly and the target 45 °F dew point is achieved. Continuous measurement of the gas temperature at the chiller outlet is required. The temperature measurement device should be located at (or immediately after) the coalescing filter or other direct contact moisture removal device that follows the chiller and removes the condensed moisture. Because the gas will be saturated at the temperature it leaves the filter, the temperature in that location is a good measure of the dew point. Temperature monitors are readily available, commonly used, reliable, and less expensive than alternative monitoring systems.

If a de-watering system that is not based on chilling, for example, a desiccant system, is used, then temperature would not be an appropriate parameter to monitor. In such cases, monitoring of the dew point would indicate whether the system is operating properly to achieve a temperature of 45 °F. Dew point can be continuously monitored using a hygrometer with a dew point readout. The hygrometer should be located after the equipment that performs the moisture removal. Dew point monitors are available and suitable for landfill gas applications.

Data collection is required at 15-minute intervals, consistent with current landfills NSPS requirements for flare pilot flame monitoring and enclosed combustor temperature monitoring that apply to landfills that opt to comply with the control options rather than the treatment option. A 24-hour block average for determining compliance with the treatment system operating parameter limits is sufficient to indicate any significant change in treatment system operation and would be less burdensome than more frequent averaging. Owners or operators of treatment systems would be required to report periods when the 24-hour block average for a monitored parameter (e.g., pressure drop, temperature, dew point) is outside the operating range established in the approved design plan.

Compliance schedule.

Landfills subject to subpart XXX that choose to comply with subpart XXX by treating the landfill gas according to 40 CFR 60.762(b)(2)(iii)(C) would comply with the treatment requirements upon choosing to control landfill gas using the treatment option.

Uses of Treated Landfill Gas.

Subpart WWW allows landfill owners or operators the option of achieving compliance by routing the collected gas to a treatment system “that processes the collected gas for subsequent sale or use.” We propose language in subpart XXX (40 CFR 60.762(b)(2)(iii)(C)) to clarify that the use of treated landfill gas is not limited to use as a fuel for a stationary combustion device as some have interpreted the provision. We clarify the intent of the treatment option to allow other beneficial uses such as vehicle fuel, production of high-Btu gas for pipeline injection, or use as a raw material in a chemical manufacturing process. Newer uses of landfill gas are being implemented and result in the production of useful energy or products, reducing the use of fossil fuels or other raw materials and the associated emissions. For the uses mentioned, the gas is treated at least as well as the specified treatment requirements. Site-specific approval of alternative monitoring parameters would be required for uses other than combustion because treatment systems for these end uses are relatively few in number and have unique designs. Owners or operators would be required to apply for approval of monitoring parameters.

B. Startup, Shutdown and Malfunction Provisions

In its 2008 decision in

Sierra Club

v.

EPA,

551 F.3d 1019 (D.C. Cir. 2008),

cert. denied,

130 S. Ct. 1735 (U.S. 2010), the United States Court of Appeals for the District of Columbia Circuit vacated portions of two provisions in the EPA's CAA section 112 regulations governing the emissions of HAP during periods of SSM. Specifically, the Court vacated the SSM exemption contained in 40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1), holding that under CAA section 302(k), emissions standards or limitations must be continuous in nature and that the SSM exemption violates the CAA's requirement that some CAA section 112 standards apply continuously.

Periods of startup or shutdown.

Consistent with

Sierra Club

v.

EPA

(551 F.3d 1019 (D.C. Cir. 2008)), the EPA has established standards in subpart XXX that apply at all times. The part 60 general provisions, which define startup, shutdown and malfunction, were written for typical industrial or manufacturing sources and associated processes. Many of these sources and processes may, at times, be shut down entirely for clean-out, maintenance, or repairs, and then restarted. Applying the standards at all times, including periods of startup and shutdown, is intended to minimize excess emissions when the source or process ceases operation or commences operation, or malfunctions. Landfill emissions, however, are produced by a continuous biological process that cannot be stopped or restarted. For landfills, the primary SSM concern is with malfunction of the landfill GCCS and associated monitoring equipment, not with the startup or shutdown of the entire source. Thus, SSM provisions in the subpart XXX focus primarily on malfunction of the gas collection system, gas control system, and gas treatment system, which is part of the gas control system.

Periods of malfunction.

Periods of startup, normal operations, and shutdown are all predictable and routine aspects of a source's operations. However, by contrast, malfunction is defined as “any sudden, infrequent, and not reasonably preventable failure of air pollution control equipment, process equipment, or a process to operate in a normal or usual manner. Failures that are caused in part by poor maintenance or careless operation are not malfunctions” (40 CFR 60.2). The EPA has determined that CAA section 111 does not require that emissions that occur during periods of malfunction be factored into development of CAA section 111 standards. Nothing in CAA section 111 or in case law requires that the EPA anticipate and account for the innumerable types of potential malfunction events in setting emission standards. CAA section 111 provides that the EPA set standards of performance which reflect the degree of emission limitation achievable through “the application of the best system of emission reduction” that the EPA determines is adequately demonstrated. A malfunction is a failure of the source to perform in a “normal or usual manner” and no statutory language compels the EPA to consider such events in setting standards based on the “best system of emission reduction.” The “application of the best system of emission reduction” is more appropriately understood to include operating units in such a way as to avoid malfunctions.

Further, accounting for malfunctions in setting emission standards would be difficult, if not impossible, given the myriad different types of malfunctions that can occur across all sources in the category and given the difficulties associated with predicting or accounting for the frequency, degree, and duration of various malfunctions that might

occur. As such, the performance of units that are malfunctioning is not “reasonably” foreseeable. See, e.g.,

Sierra Club

v.

EPA,

167 F.3d 658, 662 (D.C. Cir. 1999) (“The EPA typically has wide latitude in determining the extent of data-gathering necessary to solve a problem. We generally defer to an agency's decision to proceed on the basis of imperfect scientific information, rather than to `invest the resources to conduct the perfect study.' ”) See also,

Weyerhaeuser

v.

Costle,

590 F.2d 1011, 1058 (D.C. Cir. 1978) (“In the nature of things, no general limit, individual permit, or even any upset provision can anticipate all upset situations. After a certain point, the transgression of regulatory limits caused by `uncontrollable acts of third parties,' such as strikes, sabotage, operator intoxication or insanity, and a variety of other eventualities, must be a matter for the administrative exercise of case-by-case enforcement discretion, not for specification in advance by regulation.”). In addition, emissions during a malfunction event can be significantly higher than emissions at any other time of source operation and thus accounting for malfunctions could lead to standards that are significantly less stringent than levels that are achieved by a well-performing non-malfunctioning source. It is reasonable to interpret CAA section 111 to avoid such a result. The EPA's approach to malfunctions is consistent with CAA section 111 and is a reasonable interpretation of the statute.

In the event that a source fails to comply with the applicable CAA section 111 standards as a result of a malfunction event, the EPA would determine an appropriate response based on, among other things, the good faith efforts of the source to minimize emissions during malfunction periods, including preventative and corrective actions, as well as root cause analyses to ascertain and rectify excess emissions. The EPA would also consider whether the source's failure to comply with the CAA section 111 standard was, in fact, “sudden, infrequent, not reasonably preventable” and was not instead “caused in part by poor maintenance or careless operation” (40 CFR 60.2 (definition of malfunction)).

Further, to the extent the EPA files an enforcement action against a source for violation of an emission standard, the source can raise any and all defenses in that enforcement action and the federal district court will determine what, if any, relief is appropriate. The same is true for citizen enforcement actions. Similarly, the presiding officer in an administrative proceeding can consider any defense raised and determine whether administrative penalties are appropriate.

In several prior rules, the EPA had included an affirmative defense to civil penalties for violations caused by malfunctions in an effort to create a system that incorporates some flexibility, recognizing that there is a tension, inherent in many types of air regulation, to ensure adequate compliance while simultaneously recognizing that despite the most diligent of efforts, emission standards may be violated under circumstances entirely beyond the control of the source. Although the EPA recognized that its case-by-case enforcement discretion provides sufficient flexibility in these circumstances, it included the affirmative defense to provide a more formalized approach and more regulatory clarity. See

Weyerhaeuser Co.

v.

Costle,

590 F.2d 1011, 1057-58 (D.C. Cir. 1978) (holding that an informal case-by-case enforcement discretion approach is adequate); but see

Marathon Oil Co.

v.

EPA,

564 F.2d 1253, 1272-73 (9th Cir. 1977) (requiring a more formalized approach to consideration of “upsets beyond the control of the permit holder”). Under the EPA's regulatory affirmative defense provisions, if a source could demonstrate in a judicial or administrative proceeding that it had met the requirements of the affirmative defense in the regulation, civil penalties would not be assessed. Recently, the United States Court of Appeals for the District of Columbia Circuit vacated such an affirmative defense in one of the EPA's section 112(d) regulations.

NRDC

v.

EPA,

No. 10-1371 (D.C. Cir. April 18, 2014) 2014 U.S. App. LEXIS 7281 (vacating affirmative defense provisions in section 112(d) rule establishing emission standards for Portland cement kilns). The court found that the EPA lacked authority to establish an affirmative defense for private civil suits and held that under the CAA, the authority to determine civil penalty amounts lies exclusively with the courts, not the EPA. Specifically, the Court found: “As the language of the statute makes clear, the courts determine, on a case-by-case basis, whether civil penalties are `appropriate.' ” See NRDC, 2014 U.S. App. LEXIS 7281 at *21 (“[U]nder this statute, deciding whether penalties are `appropriate' in a given private civil suit is a job for the courts, not EPA.”). In light of NRDC, the EPA is not including a regulatory affirmative defense provision in this rulemaking. As explained above, if a source is unable to comply with emissions standards as a result of a malfunction, the EPA may use its case-by-case enforcement discretion to provide flexibility, as appropriate. Further, as the D.C. Circuit recognized, in an EPA or citizen enforcement action, the court has the discretion to consider any defense raised and determine whether penalties are appropriate. Cf. NRDC, 2014 U.S. App. LEXIS 7281 at *24. (arguments that violation were caused by unavoidable technology failure can be made to the courts in future civil cases when the issue arises). The same logic applies to EPA administrative enforcement actions.

Limit on SSM duration.

Subpart WWW limits the duration of SSM events to 5 days for the landfill gas collection system and 1 hour for treatment or control devices. Proposed subpart XXX does not include the 5-day and 1-hour time limitations because some malfunctions cannot be corrected within these timeframes. Excluding these provisions is consistent with

Sierra Club

v.

EPA

(551 F.3d 1019 (D.C. Cir. 2008)), which concluded that that emission standards apply at all times, including periods of SSM, and 40 CFR 60.11(d), which states that at all times, including periods of startup, shutdown and malfunction, owners or operators shall, to the extent practicable, maintain and operate any source facility including associated air pollution control equipment in a manner consistent with good air pollution control practice for minimizing emissions. The proposed revisions clarify that the NSPS standards continue to apply during periods of SSM.

To prevent free venting of landfill gas to the atmosphere during control device malfunctions, we propose to include a requirement in subpart XXX (40 CFR 60.763(e)) that states that in the event the collection or control system is not operating, the gas mover system must be shut down and all valves in the collection and control system contributing to venting of gas to the atmosphere must be closed within 1 hour. Note that 40 CFR 60.753(e) of subpart WWW says “inoperable.” This provision was written when there was an allowance for periods of SSM: Subpart WWW (40 CFR 60.755(e)) allows SSM periods of 5 days for the landfill gas collection system and 1 hour for periods when collection or control devices were “not operable” due to malfunction. During those periods, the emission standards do not apply. However, proposed subpart XXX states that the standards apply at all times, including periods of SSM, and there is no allowance for SSM periods. Thus,

the term “inoperable” no longer applies. The EPA proposes to use the term “not operating,” which includes periods when the gas collection or control system is not operating for whatever reason, including when the gas collection or control system is inoperable.

The practice to shut down the gas mover equipment and all valves contributing to venting of gas to the atmosphere minimizes emissions from the landfill while the control system is not operating and is being repaired. Compliance with 40 CFR 60.763(e) does not constitute compliance with the applicable standards in 40 CFR 60.762. Compliance with 40 CFR 60.763(e) is necessary to demonstrate compliance with the general duty to minimize emissions in 40 CFR 60.11(d) during control or collection system malfunctions.

Under subpart XXX, landfill owners/operators must keep records of combustion temperature, bypass flow, and periods when the flare flame or the flare pilot flame is out. However, without additional provisions, the EPA would have no way to gauge the severity of an emissions exceedance that may occur when these operating parameters are not being met or when the control device is not operating. Therefore, the EPA is including provisions for landfill owners/operators to estimate NMOC emissions when the control device or collection system is not operating. The landfill owners/operators may use whatever information is available to estimate NMOC emissions during the period, including but not limited to, landfill gas flow to or bypass of the control device, the concentration of NMOC (from the most recent performance test or from AP-42), and the amount of time the control device is not operating. Landfill owners/operators would keep records of the estimated emissions and would report the information in the annual compliance report. (See provisions in proposed subpart XXX: 60.767(f)(7) and 60.768(c)(5).)

C. Closed Areas

In the September 8, 2006 proposed amendments, the EPA requested public comments on how to address closed areas of landfills and when to allow removal of controls. Under 40 CFR 60.759(a)(3)(ii) of subpart WWW, landfills owners/operators can exclude from control, provided that the total NMOC emissions of all excluded areas can be shown to contribute less than 1 percent of the total amount of NMOC emissions from the landfill.

As discussed in the September 8, 2006 proposed amendments (71 FR 53277), it has come to our attention that there are situations in which the quantity of gas production has greatly declined in separate closed areas of some landfills, and the methane content has fallen such that the area is producing insufficient gas to properly operate a GCCS and control device. Actual measurements may show that the quantity of landfill gas from the area is less than 1 percent of the total gas from the entire landfill, but using the first order decay equation, it is calculated to be greater than 1 percent of the total gas from the entire landfill.

The EPA proposes in subpart XXX that owners or operators of physically separated, closed areas of landfills may use the procedures in 40 CFR 60.764(b), which determine the flow rate of landfill gas using actual measurements, to determine NMOC emissions. Alternatively, owners or operators of physically separated, closed areas may use subpart XXX (40 CFR 60.769(a)(3)(ii)), which relies on modeled (calculated) NMOC rates. The EPA proposes to allow the use of actual flow measurements because using actual flow measurements yields a more precise measurement of NMOC emissions for purposes of determining if NMOC emissions from the closed, nonproductive area of the landfill are less than 1 percent of the total NMOC emissions from the entire landfill. Landfills would be allowed to stop collecting gas from the closed separated area if it accounts for less than 1 percent of total landfill NMOC emissions.

The measurement approach would be allowed only in closed areas that are physically separated from other parts of the landfill (e.g., with liners). If the closed area is not separated, gas can migrate between that area and the rest of the landfill. In such a situation, measurements might not accurately reflect emissions from the given landfill area because gas could be moving underground and escaping or being collected from an adjacent section of the landfill.

D. Surface Monitoring

The landfills NSPS requires quarterly surface monitoring to demonstrate that the cover and gas collection system are working properly. The intent of the surface monitoring provision is to maintain a tight cover that minimizes the migration of emissions through the landfill surface. The operational requirements in subpart WWW specify that the landfill must “operate the collection system so that the methane concentration is less than 500 parts per million above background at the surface of the landfill. To determine if this level is exceeded, the owner or operator shall conduct surface testing around the perimeter of the collection area along a pattern that traverses the landfill at 30 meter intervals and where visual observations indicate elevated concentrations of landfill gas, such as distressed vegetation and cracks or seeps in the cover.”

Several commenters on the September 8, 2006 notice asserted that the monitoring of every cover penetration was unnecessary or too burdensome. One commenter believed quarterly monitoring of penetrations was needed and suggested rule amendments to require the surface monitoring be conducted not only in areas where distressed vegetation and cracks or seeps in the cover can be seen, but also in other areas such as at the base of gas collection wells or at the top of the gas collection boot.

In proposed subpart XXX, we are reiterating the position that landfills must monitor all cover penetrations and openings within the area of the landfill where waste has been placed and a gas collection system is required. Specifically, landfill owners/operators must conduct surface monitoring at 30-meter intervals and where visual observations indicate elevated concentrations of landfill gas. Cover penetrations can be observed visually and are clearly a place where gas would be escaping from the cover, so monitoring of them is required by the regulatory language. The regulatory language gives distressed vegetation and cracks as an example of a visual indication that gas may be escaping, but this example does not limit the places that should be monitored by landfill staff or by enforcement agency inspectors. Thus, the landfill must monitor any openings that are within an area of the landfill where waste has been placed and a gas collection system is required. The EPA is clarifying this intent in 40 CFR 60.763(d), as follows: Owners/operator must also monitor “* * * where visual observations indicate elevated concentrations of landfill gas, such as distressed vegetation and cracks or seeps in the cover and all cover penetrations.”

Regarding how to monitor landfill surfaces including surface penetrations, subpart XXX states that surface emission monitoring must be performed in accordance with section 8.3.1 of Method 21 of appendix A of part 60, except that the probe must be placed within 5 to 10 centimeters of the ground.

E. Electronic Reporting

Through this proposal, the EPA is presenting a process to increase the ease and efficiency of data submittal and improve data accessibility. Specifically, the EPA is proposing that owners or operators of MSW landfills submit electronic copies of required performance test reports, NMOC emission rate reports, and annual reports by direct computer-to-computer electronic transfer through the EPA's Central Data Exchange (CDX) using the Compliance and Emissions Data Reporting Interface (CEDRI).

The CDX is the EPA's portal for submittal of electronic data. The EPA-provided ERT software is used to generate electronic reports of performance tests that will be uploaded into the CDX using the CEDRI. NMOC emission rate reports and annual reports wi

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