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August 8, 2011 

Via Electronic Transmittal: cozzie.david@epa.gov

 ward.hillary@epa.gov 

Ms. Hillary Ward 

Sector Policies and Programs Division (E143-01) 

Office of Air Quality, Planning and Standards 

U.S. Environmental Protection Agency 

109 T.W. Alexander Drive 

Research Triangle Park, NC 27709 

Dear Hillary: 

We appreciate your taking time on July 29, 2011 to discuss options for addressing closed landfill 

areas pursuant to EPA’s revisions of 40 CFR 60 Subpart WWW (Landfill NSPS). As promised, 

we prepared suggestions for a gradual step down of gas system operations due to declining gas 

production in closed landfill areas. 

The Landfill NSPS articulates design and operational standards for landfill gas collection and 

control systems (GCCS) to address gradual increases in landfill gas generation from waste 

placement activities. For example, the rule requires the owner/operator of the MSW landfill to: 

 Prepare a GCCS Design Plan that illustrates full build out of the GCCS; 

 Install gas collection in areas of the landfill where the age of the initial waste placed 

reaches the two-year or five-year milestone; and 

 Expand the GCCS where operational standards are exceeded. 

However, the Landfill NSPS requirements do not envision an analogous, step-down process for 

landfill areas on the downside of the gas generation curve that are experiencing declining gas 

flows. The provisions offer limited flexibility, employ somewhat confusing definitions, and are 

therefore often subject to varying interpretations by regulators. For example, the MSW Landfill 

owner/operator may apply to: 

 Remove GCCS equipment (this option only applies to the entire MSW Landfill); 

 Demonstrate that non-producing areas excluded from control contribute less than the 1% 

of facility NMOC emissions; 

 Request a higher operating value (HOVs) for one or more gas collectors; or 

 Decommission a gas collector (well) / seek approval for a design change such as 

removing the wellhead and capping the header line. 
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The rule does not appear to provide operational flexibility to shut-off the well, to temporarily 

lock out the vacuum, while declining gas flows preclude the well from meeting the wellhead 

pressure, temperature and oxygen standards. With an operational shut-off, if or when gas flows 

increase as determined from periodic well monitoring and surface monitoring scans, the well 

could be easily brought back on-line. 

We believe that this additional option or rule clarification for temporary shut-off of a well is 

needed because many agencies do not respond to or approve HOV or decommissioning requests 

even when sufficient documentation is provided. This appears to happen because of insufficient 

resources to process these requests, as well as differing interpretations of what 

“decommissioning” means. Absent approvals, facilities may be forced to expand the GCCS in 

the closed landfill area(s) (i.e., the default remedy in the Landfill NSPS); such expansions 

typically do not correct for exceedances and in fact can make the situation worse. It can be very 

costly to meet NSPS operational standards if the closed area with declining flow is expected to 

perform like the active landfill area with increasing gas flow. 

There are also situations where a closed portion of a larger MSW landfill may have triggered the 

fifteen year operating timeline that is now a prerequisite for equipment removal, but the entire 

MSW landfill has not. Some agencies will only allow equipment removal when the entire MSW 

landfill, rather than a closed landfill area has triggered the fifteen year requirement. Such 

interpretations render the option all but useless until the entire site’s gas collection system has 

met the fifteen year operational timeline. 

Proposed Rule Changes and Clarifications: 

As we discussed on the July 29, 2011 conference call, just as the Landfill NSPS has a step-up 

approach to collecting and controlling landfill gas, the rules need to provide for a step-down 

approach to operational shut-off and permanent decommissioning of portions of the collection 

and control system. We have identified several potential rule clarifications and solutions to 

address declining gas flows and gas quality at closed landfills or closed landfill units or areas, 

which include the following: 

1. Clarify that the definition of “closed landfill” refers to an entire landfill facility that is 

closed, as well as to a closed landfill unit or area of an MSW Landfill. Allow closed 

landfill units or areas, as well as an entire MSW Landfill to meet the NSPS rule 

provisions for a closed landfill. This would be consistent with how installation of 

controls is required by landfill area under the two- and five-year criteria prescribed in the 

NSPS rule. 

Further, clarify that provision for annual surface emissions monitoring (SEM) applies to 

closed units or areas of the MSW Landfill; where results of three consecutive quarterly 

SEM events are less than 500 ppmv methane allow a reduction to annual to annual 

testing. Currently, many agencies only allow annual SEM where the entire facility is 

closed. 
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2. Provide flexibility to operationally shut-off, as well as permanently decommission gas 

collection wells located in closed areas with declining flow and/or poor gas quality. 

Specifically, allow facility discretion to shut-off wells and continue to conduct surface 

emissions monitoring in vicinity of the wells in accordance with the rule. We 

recommend that an operational shut-off not require prior agency approval, but that the 

landfill should inspect and document physical condition of the well to demonstrate well 

integrity. We also recommend the facility maintain records of well(s) that are shut-off 

such as a log or GCCS plot map. This approach is consistent with the EPA Region V 

applicability determination issued to the Akron Regional Landfill, dated February 12, 

2003. The Region stated that it viewed an operational shut-off of the well (that keeps the 

well casings and heads in place) to be an operational change rather than a design change. 

The Akron Landfill was directed to continue surface monitoring, but was relieved of 

conforming to the wellhead operating standards. 

Meeting the NSPS operating limits at wells with declining flow and poor gas quality is 

extremely difficult to impossible. In our experience, there is minimal risk of oxygen 

intrusion after placement of final cover. Further, because the gas generation/extraction 

rate is significantly reduced the actual volume of oxygen entering the landfill is minimal 

even if the oxygen concentration of the gas itself is high. Therefore the risk for a landfill 

fire is extremely low. Further, by continuing surface monitoring in the vicinity of the 

shut-off well(s), the landfill owner/operator can assure the gas collection system is still 

operating properly, and can identify if collection should resume. Finally, operational 

shut-off should reduce paperwork burden for agencies and industry in obtaining HOVs 

and alternative timelines to address exceedances of the oxygen, temperature and pressure 

operating limits. 

3. Propose a 10% NMOC threshold for non-producing areas in order to address declining 

flows. The 10% NMOC threshold may be determined in accordance with 40 CFR 

§60.754(b) as gas collection is installed in these areas. The non-producing area(s) would 

not be subject to monthly wellhead monitoring requirements or obligations to meet 

pressure, temperature and oxygen standards for wells located in the non-producing 

area(s). 

To demonstrate that the 10% threshold is still protective of the environment, the site 

would continue to conduct monthly cover integrity inspections and quarterly surface 

emissions monitoring. If readings above 500 ppmv are not detected in non-producing 

area(s) after three consecutive quarters, then the site could defer to annual surface 

emissions monitoring as allowed in 40 CFR §60.756(f). If exceedance(s) are detected 

(above 500 ppmv), then apply corrective actions in accordance with 40 CFR 

§60.755(c)(4). The site would re-initiate quarterly monitoring until three consecutive 

quarterly events demonstrate no exceedances of 500 ppmv standard. The site would then 

defer to annual monitoring as allowed in 40 CFR 60.756(f). This proposed provision is 

supplemental to the existing 1% NMOC threshold provided for in 40 CFR 

§60.759(a)(3)(2) for non-producing areas where a GCCS would not be required at all. 
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4. Allow use of actual gas recovery data to determine when a non-productive area can meet 

the 10% and 1% NMOC thresholds. Presently, a landfill owner/operator can only use a 

LFG generation model to determine when a non-productive landfill area can meet the 1% 

requirements for NMOC emissions, and thus be relieved of control requirements (40 CFR 

60.759(a)). However, a landfill owner/operator may use actual site-specific LFG 

recovery data (measured landfill gas flow rate and NMOC concentration) to meet the 

criteria for complete removal of a GCCS at the end of NSPS compliance life (40 CFR 

60.754(b)). We believe that actual recovery data is more accurate, and its use for 

evaluating the 10%NMOC threshold is warranted and consistent with the intent of the 

regulation. 

5. Eliminate the 15-year criterion for GCCS removal, as it is subjective and has no statutory 

or scientific basis. Demonstration for GCCS removal should be performance based. 

When the MSW Landfill can demonstrate facility emissions are less than 50 Mg NMOC, 

then the GCCS requirement of the NSPS should not apply. Requiring GCCS operation in 

accordance with the NSPS when NMOC emissions are less than 50 Mg/year is 

inconsistent with the intent of the rule, and was never considered in the required financial 

impact analysis done for the NSPS. Nevertheless should the Agency choose to keep the 

15-year criterion, we recommend applying it to each portion of the MSW landfill 

independently. For example, when one landfill unit or area closes, the 15-year operations 

criterion for GCCS equipment removal starts regardless of whether other landfill units or 

areas are still active. 

6. Allow facilities to complete a Tier 2 or Tier 3 analysis at any time to defer NSPS criteria, 

as long as NSPS requirements are met to that point in time. In the NSPS rule and 

preamble, it is clear that EPA never intended to regulate landfills with NMOC emissions 

under 50 Mg/year. Therefore, whenever the MSW Landfill can demonstrate facility 

emissions are less than 50 Mg NMOC, then the GCCS requirement of the NSPS should 

not apply. It should not matter when the facility completes a Tier 2 (or Tier 3) analysis. 

Agency applicability determinations state that “late” (after 180 days from the Tier 1) Tier 

2 analyses could be conducted but not beyond the final compliance date under the NSPS 

(30 months from first exceeding 50 Mg/year). The NSPS rule is silent on this topic, and 

the requirement for a Tier 2 is voluntary. 

 
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Please contact us if you have any questions regarding our comments. Waste Management 

greatly values the successful collaboration we have shared with the Agency in developing 

protective and workable standards for MSW landfills. We look forward to our continued 

working relationship with you. 

Sincerely, 

 

Kerry Kelly, Director, Amy Van Kolken Banister, Senior Director, 

Federal Public Affairs Corporate Air Programs 

CC: D. Cozzie, USEPA, OAQPS 

 F. Caponi, LACSD 

 S. Crawford, SWANA 

 A. Marconi, DSWA 

 R. Repa, NSWMA 

 R. Strube, Veolia 

 P. Sullivan, SCS 

 N. Wuestenberg, Republic