4 The record articles

New Landfill Air Regulations May Inspire a Round of Tic Tac Toe

Posted: July 9th, 2021

Authors: Lindsey K. 

If it seems like you’ve been hearing a lot about air quality regulations for landfills over the last few years, that’s because there are seven different Subparts under Parts 60, 62, and 63 to Title 40 of the Code of Federal Regulations (CFR) that pertain to landfill air emissions.  In addition, four of those rules have been subject to 11 regulatory actions since 2014.  These rules generally require landfills to collect and control landfill gas (LFG) if and when they reach a certain capacity of waste and a certain emissions rate of non-methane organic compounds (NMOC).  Before getting into the details of the most recent rulemakings, and why they might inspire a round of Tic Tac Toe, let’s first revisit the seven different 40 CFR Subparts that pertain to landfill air emissions.

The Landfill Regulations

Many of the rules applicable to a landfill depend on when the landfill was constructed, modified, or reconstructed, which dictates whether the landfill is considered “new” or “existing.”  New landfills are regulated by Standards of Performance for New Stationary Sources, commonly referred to as New Source Performance Standards (NSPS) under 40 CFR Part 60.  Under Part 60, Subparts WWW and XXX may be applicable depending on when the landfill was constructed, modified, or reconstructed.

Existing landfills are indirectly regulated by Emission Guidelines, which are also codified under 40 CFR Part 60.  Under Part 60, Subparts Cc and Cf may be indirectly applicable depending on when the landfill was constructed, modified, or reconstructed.  Rather than applying directly to landfills, Emission Guidelines direct state, local, and tribal agencies (herein referred to as states) to develop their own State Plans to implement the Emission Guidelines.  If a state does not develop a State Plan, or the U.S. Environmental Protection Agency (U.S. EPA) does not approve a submitted State Plan, U.S. EPA will develop a Federal Plan.  Federal Plans are codified under 40 CFR Part 62.  Under Part 62, Subparts GGG and OOO may be applicable depending on when the landfill was constructed, modified, or reconstructed.

While the six NSPS and Emission Guidelines regulate emissions of criteria and other pollutants pursuant to Section 111 of the Clean Air Act (CAA), the seventh rule is a National Emission Standard for Hazardous Air Pollutants (NESHAP) under 40 CFR Part 63, which regulates emissions of hazardous air pollutants (HAP) pursuant to Section 112 of the CAA.  Under Part 63, Subpart AAAA may be applicable depending on the landfill’s size, NMOC emissions rate, and HAP emissions rate.

Rule History

Prior to 2014, Emission Guideline Subpart Cc, NSPS Subpart WWW, Federal Plan Subpart GGG, and NESHAP Subpart AAAA were potentially applicable to a landfill.  NESHAP Subpart AAAA was amended on March 26, 2020 and remains an applicable rule for landfills.  However, rather than amending Emission Guideline Subpart Cc, NSPS Subpart WWW, and Federal Plan Subpart GGG, U.S. EPA promulgated new Emission Guideline Subpart Cf, NSPS Subpart XXX, and Federal Plan Subpart OOO over the span of approximately five years, effectively making the three previous rules obsolete once the new rules became effective, and potentially changing the regulation to which a landfill had been subject.  For example, a landfill that was modified on or before July 17, 2014 that had been subject to NSPS Subpart WWW under 40 CFR Part 60 may now be subject to Federal Plan Subpart OOO under 40 CFR Part 62, or the State Plan (if developed by their state and approved by U.S. EPA).

NSPS Subpart XXX was proposed on July 17, 2014 and finalized on August 29, 2016, with an effective date of October 28, 2016.  Therefore, any affected landfills that commenced construction, modification, or reconstruction after July 17, 2014 became subject to NSPS Subpart XXX on October 28, 2016.  Emission Guideline Subpart Cf was proposed on August 27, 2015 and finalized on August 29, 2016 (the same day as the final NSPS Subpart XXX).  The newest rule, Federal Plan Subpart OOO, was proposed on August 22, 2019, signed on May 10, 2021, and published in the Federal Register just 11 days later on May 21, 2021 with an effective date June 21, 2021.  The relatively quick turnaround for implementing a regulation was likely due to U.S. EPA’s recent focus on climate change, to which landfills contribute due to their emissions of methane.  U.S. EPA acknowledged the short timeline, stating in the preamble to the Federal Register notice that Emission Guideline Subpart Cf was published “over 3 years prior to the publication of the proposed Federal plan;” in other words, these requirements shouldn’t come as a surprise.

Subparts XXX and OOO (Tic Tac Toe!)

NSPS for new sources are generally more stringent than Emission Guidelines (i.e., State or Federal Plans) for existing sources.  In this case, however, NSPS Subpart XXX and Federal Plan Subpart OOO are fairly consistent.  For example, both Subparts XXX and OOO reduced the NMOC applicability threshold from 50 megagrams per year (Mg/year) to 34 Mg/year (Subpart OOO retained the 50 Mg/year threshold for closed landfills), removed the corrective action requirements for wellhead oxygen and nitrogen operating parameters, and added a Tier 4 option to demonstrate surface methane emissions are less than 500 parts per million (ppm) via surface emissions monitoring (SEM) before triggering the requirement to install a gas collection and control system (GCCS).

Subparts XXX and OOO also added an option to comply with the “major compliance provisions” of NESHAP Subpart AAAA “in lieu of complying with the analogous provisions in the NSPS and EG.”  As implied by this option, NESHAP Subpart AAAA is also very similar to Subparts XXX and OOO.  While it has a less stringent (i.e., higher) temperature parameter limit, it has additional corresponding enhanced monitoring and reporting requirements.  Subpart AAAA also has additional requirements for landfills with bioreactors.

Newly effective Federal Plan Subpart OOO contains provisions for existing “legacy controlled landfills” that already have a GCCS in place (i.e., they are not expected to redo certain specified previously completed compliance obligations), as well as increments of progress for previously uncontrolled existing landfills to meet the requirements (i.e., they are not expected to comply on day one).  Uncontrolled landfills now subject to Federal Plan Subpart OOO must submit a design capacity report (and an NMOC emissions rate report if the capacity equals or exceeds 2.5 million Mg and 2.5 million cubic meters) by September 20, 2021.  Future requirements will depend on the NMOC emissions rate; once greater than 34 Mg/year (50 Mg/year for closed landfills), and if surface methane emissions exceed 500 ppm for those choosing to utilize the new Tier 4 option, the landfill will be required to install a GCCS according to specified increments of progress.  The first increment is due one year after the NMOC emissions rate report in which NMOC emissions equaled or exceeded 34/50 Mg/year, and the last increment (i.e., achieving final compliance) is due 30 months after that report.

Applicability & Permitting Considerations

U.S. EPA issued a finding of failure on March 12, 2020 for 42 states to submit State Plans in response to Emission Guideline Subpart Cf, which were due by May 30, 2017; therefore, the Federal Plan is expected to impact many landfills that would otherwise be subject to a State Plan.  Indeed, U.S. EPA states in the preamble to the Federal Register notice that “there are an estimated 1,590 landfills covered by this final Federal plan.”  While previously unregulated landfills may not be looking forward to their new compliance obligations, previously regulated landfills have been waiting almost five years for Emission Guideline Subpart Cf to be implemented, which relaxes certain requirements like the oxygen and nitrogen operating parameter limits compared to the previously applicable rule(s).  However, a previously regulated landfill’s operating permit will still reflect the previously applicable rule(s) until it is amended, so landfill operators should make sure to demonstrate compliance with all requirements until they are able to complete the permit amendment process.

Additionally, until a state requests delegation of authority to implement Federal Plan Subpart OOO, U.S. EPA remains the Administrator.  Even after delegation, U.S. EPA “will continue to hold enforcement authority along with the state or tribe,” but the state will have responsibility for “administration and oversight of compliance, reporting, and recordkeeping requirements, MSW landfill inspections, and preparation of draft notices of violation.”  There are also certain other authorities that cannot be delegated to a state, which generally include alternatives and waivers for certain requirements.

If you would rather play a round of Tic Tac Toe than try to keep all of the landfill air regulations straight, please contact Lindsey Kroos at lkroos@all4inc.com or 610.933.5246 x122 so she can answer your questions about how NSPS Subpart XXX, Federal Plan Subpart OOO, or any of the other landfill regulations may impact your facility.


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