Landfills, XXX Rated!



Sure, MSW Landfills are a bit trashy, but at only 1.7 percent of all GHG emissions in the U.S., these sources are receiving quite a bit of attention from the EPA.  This article provides an update on new and important regulatory proposals related to the necessary business of “talking trash.”

EQ_Landfill photo1The “existing” performance standards for municipal solid waste (MSW) landfills were originally proposed on May 30, 1991 and subsequently finalized on March 12, 1996.  These New Source Performance Standards (NSPS) and Emission Guidelines (EG) have been the subject of numerous subsequent corrections and proposed amendments.  However, the MSW landfill industry has not been subject to any substantive rule changes since the Standards and Guidelines were originally promulgated in 1996.  While every few years EPA appears to take one step forward and seemingly two steps back in its mission to revise the landfill standards, EPA may have inched closer (yet again) to finalizing new standards for landfills.  The following sections discuss recent actions from EPA on both the landfill new source performance standards and the emission guidelines applicable to “existing” sources.

Proposed MSW Landfill NSPS Subpart XXX

Only July 17, 2014, the U.S. EPA issued a proposed rule (NSPS Subpart XXX) to update the existing Standards of Performance for Municipal Solid Waste Landfills.  The proposed rule would apply to landfills that commence construction, reconstruction or modification (e.g., an increase in the permitted volume design capacity of the landfill through either a horizontal or vertical expansion) after July 17, 2014.  NSPS Subpart XXX introduced or clarified several new concepts (in comparison to the current new source standard, NSPS Subpart WWW), including the following:

  • Establishment of 40 megagram per year (Mg/yr) generation (or emission rate) threshold for nonmethane organic compounds (NMOC) for installation of a gas collection and control system (GCCS)
  • Clarification on the use of treated landfill gas
  • Clarification on what constitutes treated landfill gas (with specific numerical values to define filtration and dewatering)
  • Removal of Startup, Shutdown and Malfunction exemptions
  • Improvements to criteria for exempting areas from collection and control
  • GCCS design plan update requirements
  • Clarification on when alternative corrective action timelines must be requested (implying that some notification is required within 15 days)

On August 14, 2015, the EPA Administrator signed a supplemental proposal for the Standards of Performance for Municipal Solid Waste (MSW) Landfills (NSPS Subpart XXX) to address the NMOC emission rate threshold at which an MSW landfill must install gas collection and control.  Again, EPA’s review of the NSPS for MSW Landfills applies to landfills that commenced construction, reconstruction, or modification after July 17, 2014.

This most recent rule proposal aims to achieve additional reductions of landfill gas (LFG) emissions, largely focused on methane, through a lower emission threshold at which landfills must install and operate a GCCS.  The recent proposal lowers the initially proposed 40 Mg/yr NMOC emission rate threshold (for installation of a GCCS) to an NMOC emission rate of 34 Mg/yr. 

EPA is specifically requesting comment on the appropriateness of the proposed 34 Mg/yr threshold, which it claims would achieve even higher reductions in methane emissions than originally estimated.  EPA is also requesting feedback on the number of facilities that may ultimately become subject to the new Subpart XXX (based on the stated applicability date).  Comments must be received by EPA within 60 days from the date this proposed rule was published in the Federal Register (or by October 26, 2015).  EPA is not accepting any comments on last year’s proposed rulemaking during this comment period.

The proposed NSPS from July 17, 2014 is consistent with the President’s Climate Action Plan and associated Methane Strategy. EPA claims that the new supplemental proposal is based on updates to the model that estimates emission reductions and cost impacts of changes to the design capacity thresholds and/or the NMOC emission rate triggers.  The language within the Federal Register provides some of EPA’s justification for the NMOC threshold reduction.  EPA indicates that the July 17, 2014 NSPS proposal considered emission reductions and costs associated with 17 new “greenfield” MSW landfills that it estimated would commence construction, reconstruction or modification between 2014 and 2018 (with a design capacity above 2.5 million m3 and 2.5 million Mg).  As a result of public comment and additional research (relative to the original emission reduction and cost impact dataset), EPA now projects (one year later) that the number of landfills expected to be affected by proposed Subpart XXX went from 17 new landfills to 140 new or modified landfills.  Considering this change, EPA now asserts that lowering the NMOC emission rate threshold to 34 Mg/yr NMOC would accelerate the schedule for installing a GCCS and increase the number of landfills required to install a GCCS, thereby yielding additional NMOC and methane emission reductions.
EQ_Landfill photo2

Newly Proposed Emission Guidelines for MSW Landfills (Subpart Cf)

On July 17, 2014, EPA issued an Advanced Notice of Proposed Rulemaking (ANPRM) to request public input on methods to reduce emissions from existing MSW landfills.  EPA’s goal was to utilize responses from the ANPRM to determine whether additional changes to NSPS Subpart WWW (beyond those proposed for new sources under proposed Subpart XXX) were warranted.

Through the August 14, 2015 proposed rulemaking, EPA is now proposing a new subpart (Cf) that updates the Emission Guidelines (EG) and Compliance Times for Municipal Solid Waste Landfills that were originally promulgated in 1996.  This proposed subpart applies to landfills that accepted waste after November 8, 1987 and commenced construction, reconstruction, or modification on or before July 17, 2014.  The proposed EG is expected to yield additional reductions of LFG and its components, including methane, by lowering the thresholds at which a landfill must install a GCCS.  The August 27, 2015 proposal incorporates information from last year’s ANPRM and addresses other topics such as surface emissions monitoring, wellhead monitoring, and the definition of a landfill gas treatment system.  The proposed changes are based on EPA’s review of “advances in technology and operating practices” and are consistent with the President’s 2013 Climate Action Plan and Methane Strategy. 

Landfills currently subject to 40 CFR Part 60, Subparts Cc and WWW would be considered “existing” sources and would ultimately be affected by the future, final version of these proposed Emission Guidelines (Subpart Cf).  Landfills that are constructed, modified (expanded), or reconstructed after July 17, 2014 would be subject to the new Subpart XXX (for “new” sources), discussed above.  In general, Subpart WWW sources would continue to comply with that Subpart until they become subject to the new EG (as implemented through a revised State or Federal Plan).  States will have nine months (from rule promulgation) to submit a State Plan to EPA.  A revised Federal plan (40 CFR Part 62, Subpart GGG) will apply in States that either do not submit a State Plan or have not received EPA approval.

EPA claims that the proposed revisions to the EG, once implemented through a revised State or Federal plan, would further reduce emissions of nonmethane organic compounds and methane.  Comments on the proposed rule must be received by EPA on or before October 26, 2015.

A summary of the major provisions of the proposed rule includes the following:

Threshold for installing or removing controls: The NMOC emission threshold for the installation and removal of a GCCS is reduced from 50 Mg/yr to 34 Mg/yr.  Landfills with a design capacity above the existing 2.5 million cubic meter and 2.5 million megagram threshold must install a GCCS within 30 months after exceeding an NMOC level of 34 Mg/yr.  This is consistent with the 8/14/15 supplemental proposal related to NSPS Subpart XXX.

Emission Threshold Determinations:  EPA is proposing an optional site-specific emission threshold determination (called Tier 4) to determine when a site must install and operate a GCCS.  Tier 4 is a surface emission monitoring procedure that can be used by sites that exceed the applicable NMOC emission threshold using Tiers 1, 2, or 3, to avoid the GCCS installation requirement.  By demonstrating that surface concentrations of methane are below 500 ppm for four consecutive quarters, and semi-annually thereafter, a facility would avoid the requirement to install a GCCS even if the new 34 Mg/yr NMOC threshold was exceeded using Tier 1, 2, or 3.  Please keep in mind that the provision creates a “sudden death” scenario that triggers the GCCS installation requirement at the first detection of a methane “hit” while using the Tier 4 approach. 

Landfill Gas Treatment:  EPA is clarifying that use of treated gas collected using the NSPS required GCCS systems is not limited to stationary combustion devices.  EPA recognizes other beneficial uses such as vehicle fuel, high-Btu gas generation for pipeline injection, and as a raw material (for chemical production).  In addition, EPA is again proposing to define the terms “Treated landfill gas” and “Treatment system.”  A treatment system is a system that filters, de-waters, and compresses LFG for sale or beneficial use.  The proposed definition allows for the level of treatment to be specific to the type and design of the end use of the gas.  A site-specific treatment system monitoring plan would be utilized (with appropriate recordkeeping) to define the monitoring parameters for each aspect of treatment (filtration, de-watering and compression).

Surface Methane Monitoring:  The proposal “confirms” the interpretation of several EPA Regions by requiring monitoring of all surface penetrations at existing landfills that have exceeded the NMOC generation threshold.  Landfill owners are required to conduct surface monitoring on a quarterly basis at the specified intervals, including areas where visual observations indicate elevated concentrations of LFG. 

Wellhead Operational Standards:  EPA is proposing to remove the operational standards for temperature and nitrogen/oxygen at wellheads in NSPS applicable GCCS systems.  Facilities would still be required to monitor and record temperature and oxygen/nitrogen on a monthly basis, but they would not be required to take corrective action based on that data.  Corrective action would continue to be required at any monthly wellhead check where the wellhead was found to be at non-negative pressure.

Closed Landfills:
EPA is proposing a separate subcategory for landfills that closed on or before August 27, 2015.  To avoid already-closed landfills being required to install new GCCS systems only as a result of the reduction in the LFG generation threshold, these landfills will remain subject to an NMOC emission threshold of 50 Mg/yr for determination of when controls can be installed or removed.

Low LFG Producing Areas:  EPA is proposing an alternative criteria for demonstrating when portions of an NSPS applicable GCCS can be capped or removed (due to low LFG production).  The proposal would allow for portions of the GCCS to be removed when the landfill or area is closed, the GCCS has operated for at least 15 years (or a demonstration can be made that there is not enough gas to accommodate 15 years of operation), and the owner/operator can demonstrate that there are no surface methane emissions of 500 ppm or greater in the subject area for four consecutive quarters.

Startup, Shutdown, Malfunction (SSM):  Similar to requirements under most new source performance standards, EPA is proposing that standards in the EG apply at all times, including periods of SSM.  It is also proposing recordkeeping and reporting requirements to estimate emissions during periods of SSM.

The preamble to the proposed EG also indicates that EPA is specifically seeking comment (prior to October 26, 2015) on several provisions including the following:

  • Defining “closed areas” of open landfills
  • Changing the walking pattern spacing for surface emissions monitoring from 30 meters to 25 feet
  • Adding an average methane concentration limit of 25 ppm (integrated reading)
  • Separate handling of “wet landfills”
  • Requiring monitoring of the LFG flow rate at individual wells
  • Establishing a process for third-party GCCS design plan certification

EPA is also proposing two criteria to determine when an affected source must update its GCCS design plan.  These criteria include: 1) within 90 days of expanding operations to an area not covered by the existing, approved plan, and 2) prior to installing or expanding the GCCS in a manner not consistent with the existing, approved plan.

This rule proposal for existing MSW landfills includes several provisions that could substantially reduce the regulatory burden that has been experienced by landfill owners and operators for nearly two decades.  Removal of wellhead requirements for temperature and oxygen/nitrogen would allow operators to tune their wellfields in a manner that is consistent with current field conditions, gas generation rates, and gas quality rather than arbitrary regulatory limits.  In addition, EPA has appropriately indicated that it anticipates a drastic reduction in the number of alternative timeline requests by eliminating the operational standards for wellhead oxygen/nitrogen and temperature.  The use of surface emission monitoring for determining the need to install or ability to remove a GCCS from the landfill (or subject areas) represents a valuable option and tool for landfill operators.  Minimization of surface emissions now plays an important and logical role in dictating current and future operation of a facility’s GCCS.

Trinity Consultants will continue to monitor EPA activity with regard to the proposed Performance Standards and Emission Guidelines for MSW Landfills.  Our team of landfill savvy engineers and scientists are available to assist with navigating the current standards, participating in the rulemaking for the new standards, demonstrating compliance, and leveraging the rules upon their promulgation (within the next year…or so).