On August 14, 2015, the U.S. Environmental Protection Agency (EPA) proposed updates to its 1996 Emission Guidelines for existing municipal solid waste (MSW) landfills to further reduce emissions of methane-rich landfill gas. In a separate action, the agency issued a supplemental proposal to their July 17, 2014 proposed regulation intended to reduce emissions from new and modified landfills, New Source Performance Standard (NSPS) Subpart XXX. Both actions are part of the Obama Administration’s Climate Action Plan − Strategy to Reduce Methane Emissions.
The new subpart (40 CFR 60, Subpart Cf) updates the Emission Guidelines and Compliance Times for Municipal Solid Waste (MSW) Landfills and if finalized as proposed will apply to existing MSW landfills that commenced construction, modification, or reconstruction on or before July 17, 2014, and received waste after November 8, 1987 (80 FR 52099). Landfills that fall into this category that are currently subject to 40 CFR part 60, subparts Cc and WWW would be considered “existing” under Subpart Cf and would ultimately be affected by any changes to the Emission Guidelines resulting from this review. Since the revised Emission Guidelines apply to existing sources, any source that is not subject to new subpart XXX (proposed on July 17, 2014) could become subject to the revised Emission Guidelines. Sources currently subject to subpart WWW would need to continue to comply with the requirements in that rule unless and until they become subject to more stringent requirements in the revised Emission Guidelines as implemented through a revised state or federal plan.
An estimated 989 open and closed landfills would be subject to the proposed Emission Guidelines. Of these, 574 currently are required to collect and control their emissions. Under the proposed updates, an additional 106 open landfills would be required to collect and control landfill gas emissions, bringing the total number of open and closed landfills collecting and controlling emissions from 574 currently to 680 in 2025. EPA projects that 105 open landfills would have to report their emissions but would not be required to collect them.
Proposed Updates to NSPS Subpart XXX
On July 17, 2014, the EPA proposed a new NSPS subpart, Standards of Performance for Municipal Solid Waste Landfills That Commenced Construction, Reconstruction, or Modification on or After July 17, 2014, (40 CFR part 60, subpart XXX) based on its ongoing review of the MSW Landfills NSPS (40 CFR part 60, subpart WWW) (79 FR 41796).
The August 2015 update proposes to achieve additional reductions in emissions of landfill gas (LFG) and its components, including methane, through a lower emission threshold at which MSW landfills must install and operate a gas collection and control system (GCCS). The July 2014 proposed included a lowering of the NMOC emissions threshold at which controls are required for MSW landfills from 50 megagrams per year (Mg/yr) to 40 Mg/yr. The new proposal includes a further lowering, from 40 Mg/yr to 34 Mg/yr of this threshold. EPA states that this change is based on additional data reviewed that indicates greater potential for reductions in methane emissions from these sources than they originally estimated could be achieved at reasonable cost.
Proposed Emission Guidelines for MSW Landfills
The proposed 40 CFR Part 60, Subpart Cf, Emission Guidelines and Compliance Times for Municipal Solid Waste Landfills, requires submittal of a State plan to the EPA by the Administrator of an air quality program in a State or United States protectorate with one or more existing MSW landfills that commenced construction, modification, or reconstruction on or before July 17, 2014, and received waste after November 8, 1987. States would have nine (9) months to prepare or update state plans to implement the proposed guidelines, with plans due after the final emission guidelines are issued.
The proposed Emission Guidelines would retain a number of current requirements included in the current Emission Guidelines found at 40 CFR 60, Subpart Cc, including:
- Existing landfills would be subject to the guidelines if they have a design capacity of 2.5 million metric tons and 2.5 million cubic meters of waste.
- A well-designed and well-operated landfill gas collection and control system would be the best system of emission reductions for controlling landfill gas. Landfill owners/operators may control gas by putting it to beneficial use by combusting it in an enclosed combustion device (such as a boiler, engine or turbine) for energy generation, by using a treatment system that processes the collected gas for sale, or by flaring it.
- Landfills subject to the proposed guidelines would have 30 months after reaching the emissions threshold to install and begin operating a gas collection and control system.
- Landfill owners/operators with a gas collection and control system would to be required to expand that system into new areas of the landfill within five years for active areas, and two years for areas that are closed or at final grade.
The proposed Emission Guidelines would add additional measures as well, including:
- The agency is proposing to update the emissions threshold that triggers a requirement to install landfill gas collection and control systems. That annual threshold, currently set at 50 metric tons (written as megagrams in the proposal) of nonmethane organic compounds, would change to 34 metric tons for active landfills under the proposed guidelines. This is the same threshold EPA is proposing for new landfills. Closed landfills would remain subject to the current threshold of 50 metric tons per year.
- An alternative, site-specific method for determining when a landfill must install and operate a gas collection and control system. Using this method, which is based on surface emissions monitoring, a landfill would not be required to collect and control landfill gas if it can demonstrate that emissions of methane are below 500 parts per million for four consecutive quarters. EPA also is proposing to allow a similar, site-specific method for determining when controls can be removed.
- Elimination of the wellhead operating limits for oxygen, nitrogen and temperature; however, the limits for negative pressure would remain in place. Landfills would continue to monitor and record temperature and oxygen/nitrogen levels at wellheads to help them determine whether adjustments to their gas collection and control systems are necessary.
- A number of clarifications, including clarifying that the use of treated landfill gas is not limited to use as a fuel for stationary engines but also may be used for other beneficial purposes.
Opportunity for Submittal of Comments
Comments on either proposal must be received on or before October 26, 2015. Under the Paperwork Reduction Act (PRA), comments on the information collection provisions are best assured of consideration if the Office of Management and Budget (OMB) receives a copy of your comments on or before September 28, 2015. Comments should identify Docket ID No. EPA-HQ-OAR-2014-0451.
The proposed updates and the supplemental proposal for new landfills are available here.