Regulations Updates

Published on Monday, July 18, 2016

EPA Finalizes New Emission Guidelines (EG) & New Source Performance Standards (NSPS) for MSW Landfills

Effective July 14, 2016


On July 14, 2016, the U.S. Environmental Protection Agency (EPA) finalized two new regulations to reduce emissions of methane from municipal solid waste (MSW) landfills.  The most significant change that has been included in both regulations is a decrease in the non-methane organic compound (NMOC) emission rate threshold which triggers the requirement to install and operate a landfill gas collection and control system (GCCS).  EPA has decreased this NMOC threshold from 50 Mg/yr to 34 Mg/yr.  Closed landfills remain subject to the current threshold of 50 Mg/yr.  It should be noted that EPA retained the same design capacity size thresholds of 2.5 million metric tons and 2.5 cubic meters as was currently regulated.   


The final Emission Guidelines (EG) apply to existing landfills that began construction, reconstruction or modification on or before July 17, 2014, and accepted waste after November 8, 1987.  The new EG regulation 40 CFR 60 Subpart Cf replaces Subparts WWW and Cc.  The New Source Performance Standard (NSPS) 40 CFR Subpart XXX applies to landfills constructed, modified or reconstructed after July 17, 2014. 


Many landfills will now be required to install and operate a GCCS in accordance with these regulations.  EPA estimates an additional 93 open landfills would be required to collect and control landfill gas emissions as a result of this change.  In addition, this change may extend the operational requirements of existing GCCSs.  As part of this ruling, EPA has confirmed that a well-designed and well-operated GCCS remains the best system of emission reduction for controlling landfill gas. 


For existing sites that are not required to operate a GCCS:  For existing sites that do not have NMOC emission rates exceeding 50 Mg/yr, but are reporting Annual NMOC Emission Rates near or exceeding 34 Mg/yr, there is the potential for big changes.  Gas collection and control could soon be a requirement; however, EPA has included in the final rule an alternative to Tier 2 or Tier 3 site-specific gas sampling methods for emission threshold determinations. This alternative emission threshold determination, referred to as “Tier 4,” is based on surface emission monitoring to demonstrate that surface emissions are below a specific threshold: 


  • Tier 4:  Tier 4 allows sites already actively collecting landfill gas to rely on a well-designed and operated GCCS in lieu of becoming subject to EPA gas collection and control requirements.  If surface emissions monitoring (SEM) shows that 4 consecutive quarters are below 500 parts per million by volume (ppmv) of methane at the landfill surface, the facility remains exempt from the GCCS monitoring and reporting requirements.  Once an exceedance of the 500 ppmv is recorded, the GCCS requirement is triggered, and the facility must submit a GCCS Design Plan and comply with the applicable recordkeeping, monitoring and reporting requirements.  Tier 4 is allowed only if the landfill owner or operator can demonstrate that NMOC emissions are greater than or equal to 34 Mg/yr, but less than 50 Mg/yr using Tier 1 or Tier 2.  If both Tier 1 and Tier 2 indicate NMOC emissions of 50 Mg/yr or greater, Tier 4 cannot be used (a landfill need not model emissions under Tier 3 before using Tier 4). 


For existing sites that are required to operate a GCCS:  The following are changes to GCCS monitoring, recordkeeping and reporting requirements:


  • Wellhead Monitoring:  Monthly monitoring for temperature and pressure at wellheads is still required, as is the requirement to take corrective action for elevated temperature or positive pressure.  The rule retains requirements to monitor nitrogen/oxygen levels on a monthly basis, but requirements for corrective action for these parameters have been removed. For pressure/temperature exceedances, corrective action must be initiated within 5 days.  If correction of the exceedance cannot be achieved within 15 days, the owner or operator has up to 60 days after the first measurement exceedance to conduct a root cause analysis and correct the exceedance.  Additional time may be requested based on site specific corrective action analysis and submittal of an implementation schedule.    


  • Surface Monitoring:   All surface penetrations are now required to be monitored during quarterly surface emissions monitoring (SEM) events in addition to the traverse already conducted.   In addition, the latitude and longitude of each surface emission exceedance must be measured with an instrument accuracy of at least 4 meters and reported in the SEM Report. 

  • Treated LFG:  The proposed regulation clarifies that 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 such as vehicle fuel, and high-BTU gas to pipeline.  Owners or operators must develop a site-specific treatment system monitoring plan that includes monitoring parameters addressing all three elements of treatment (filtration, de-watering, and compression) to ensure the treatment system is operating properly for each intended end use of the treated LFG.  The treatment system monitoring plan is required to be submitted as part of a Title V Permit Application, and treatment system operating parameters can be included in the permit as applicable enforceable requirements.


  • Criteria for Removing GCCS:   Removal of the GCCS is now allowed if the following criteria are met:  (1) the landfill is closed; (2) GCCS must have operated for 15 years or you must show that the GCCS could not operate for 15 years due to declining landfill gas collection; and (3) the calculated NMOC emission rate at the landfills is less than 34 Mg/yr on three successive test dates.  For existing closed landfills, the NMOC emission rate threshold for removing controls remains 50 Mg/yr. 


  • Low Producing Areas:  The new rule allows the use of actual flow data to determine NMOC emissions for the calculation of NMOC emissions from low-producing areas to evaluate emissions against the existing 1 percent criteria level for NMOC emissions when compared to the entire site.    

  • Startup, Shutdown and Malfunction Provisions:  EPA has clarified that emission limits apply at all times, including periods of startup, shutdown, and malfunction (SSM).  All valves that could vent to the atmosphere must be closed within 1 hour of a gas mover system shutdown.  The 5-day exemption for SSM periods has been removed from the regulation. 

  • Requirements for Updating the Design Plan:  GCCS Design Plans are now required to be updated within 90 days of expansion of the GCCS into a new area not covered by the previously approved design plan, or if changes made to the GCCS are not consistent with the current plan.  The landfill owner or operator must notify the Administrator that the plan is completed and provide a copy of the plan’s signature page.  The Administrator has 90 days to decide if the plan needs to be submitted for review.    



For new sites or sites undergoing a modification:  These sites will be subject to the new NSPS Subpart XXX.  The requirements of NSPS Subpart XXX are similar to the new EG requirements.  GCCS installation and monitoring will not be required under this regulation as long as the NMOC emission rate remains less than 34 Mg/yr.  EPA estimates that 128 new, modified or reconstructed landfills will be subject to the new NSPS rule.   


EPA has also provided minor changes/clarifications to the rule including:


  • Emission Testing:  EPA Method 25A is included as an approved method for testing low NMOC concentrations on the control device exhaust.  EPA Method 18 will not be allowed for NMOC analysis, but can be used in conjunction with Method 25A


  • Waste Definitions:  EPA has clarified the definitions of “household waste” and “segregated yard waste”. 

  • Electronic Reporting:  EPA has included a requirement for electronic reporting of required performance test reports, NMOC emission rate reports, and annual reports.


  • Wet Landfill Reporting:  In the final ruling, EPA stated that they did not receive enough information on wet landfills to support additional action such as separate emission thresholds, so they are continuing with the study.  As part of this, facilities are now required to report information on leachate recirculation and/or liquid addition.  This information will be submitted electronically to EPA per the new electronic reporting requirements.



States will have nine months after the guidelines are published in the Federal Register to submit state plans for implementation the final guidelines.  


For a copy of both rules and associated implementation information and fact sheets:

Number of views (2436)
Kyle Williams, P.E.
Kyle Williams, P.E.>

Kyle Williams, P.E.

Kyle Williams provides environmental engineering services for environmental investigation, air quality, and remediation projects. Other posts by Kyle Williams, P.E.
Contact author Full biography