Jun 02, 2010
Summary of EPA’s Technical Corrections to the Mandatory Greenhouse Gas Reporting Rule
On May 27, 2010, the Administrator signed a proposed rule that includes technical corrections, clarifications, and other amendments to the Greenhouse Gas Mandatory Reporting rule (MRR), which was published on October 30, 2009 (40 CFR part 98). Several of the proposed changes would affect how greenhouse gases (GHGs) are reported from landfills under Subpart HH of the Rule. Briefly, these changes include:
- Clarification of the definition of a landfill gas (LFG) collection system to exclude passive vents and flares;
- Specific exclusion of hazardous waste, C&D, and industrial landfills from the Rule;
- Clarification of how undocumented historical waste disposal amounts are to be calculated;
- Clarification of how current and future waste acceptance rates are to be calculated;
- Revision to how LFG generation is to be calculated;
- Clarification of how LFG parameters are to be measured; and
- How leachate recirculation is to be considered along with average annual rainfall when determining k values.
Public comments to these changes must be received by EPA by July 11, 2010. A public hearing must be requested by June 3, 2010.
RSG will continue to monitor the EPA web site for final passage of these proposed changes.
§98.6 clarifies the definition of a “gas collection system or landfill gas collection system” as a system of pipes used to collect landfill gas from different locations in the landfill by means of a fan or similar mechanical draft equipment to a single location for treatment (thermal destruction) or use. This definition specifically excludes “passive” systems.
§98.340(b) specifically excludes Subtitle C or TSCA hazardous waste landfills, dedicated construction and demolition (C&D) waste landfills, and industrial waste landfills.
§98.343(a)(1) clarifies the method for calculating annual modeled methane generation using Equation HH-1. The start year is revised to be 1960 (if the actual start years is unknown), instead of 50 years prior to the year of emissions estimates, as previously stated.
§98.343(a)(3) specifies how annual quantities of waste disposed in the landfill are to be calculated. (a)(3)(i)(A) specifies that direct measurements of each load be made by weighing each vehicle or container as it enters the landfill, and again after it has off-loaded the waste. Alternately, (a)(3)(i)(B) allows for vehicle tare weights to be used in lieu of measuring the “outbound” weight of the vehicle or container. At least five (5) of each vehicle or container types must be weighed after off-loading to establish a representative tare weight.
EPA originally assumed that all MSW landfills were equipped with scales, however, several commenters to the final rule indicated that is not the case. Additionally, although EPA intended that disposed waste quantities be determined by direct scale measurements, the rule may be interpreted to allow other methods. Therefore, EPA revised (a)(3)(ii) to allow for the mass capacity of each vehicle or container type to be determined by volume and density measurements, and recording the number of each vehicle or container type. The annual waste disposal amount is then determined by multiplying the number of vehicles or container types by their mass capacity. Density may be determined for different vehicle or container types with portable wheel or axle scales.
Several significant changes are made to Table HH-1 – Emission Factors, Oxidation Factors, and Methods, as follows:
Regarding waste modeling, k value determination has been changed so that, in addition to average annual rainfall, leachate recirculation, in inches per year, must also be considered. Annual inches of leachate recirculation is to be determined by dividing the total volume of leachate recirculated by the area of the portion of the landfill (presumably receiving recirculated leachate), with appropriate conversion factors.
The parameter for Lo is replaced by DOC (bulk waste), with a default value of 0.20.
DOC and k values of 0 are also assigned for inerts (e.g., glass, plastics, metal, and cement).
Changes to Table HH-2 – U.S. Per Capita Waste Disposal Rates are made for years 1989 through 2009.
Changes to Table HH-3 – Landfill Gas Collection Efficiencies are made to differentiate between final soil covers with a minimum of three (3) feet thickness of clay and/or geomembrane, and those with less than three (3) feet of clay and no geomembrane.
Additionally, several minor revisions and clarifications have been made, as follows:
§98.343(a)(4) specifies that historical waste disposal quantities should only be determined once.
§98.343(b)(1), Equation HH-4 is revised to delete the conversion factor for minutes per day (1,440), and compensates for this change by redefining (V)n as cumulative instead of daily volumetric flow. Equation HH-4 also specifies how volumetric flow is to be corrected for moisture (if needed) by replacing the term [1-(fH2O)n] with (KMC).
Throughout §98.343 (b), including Equation HH-4, measurement periods are defined for methane concentration, temperature, pressure, and, if needed, moisture content as occurring once each calendar week, with at least three (3) days between measurements.
§98.346(a) specifies how leachate recirculation during the previous 10 years is to be reported.
§98.346(b) specifies how historical waste disposal data are to be reported.
§98.346(f) requires reporting of specific cover (i.e., organic, clay, sand, or other) types used, and the surface areas of each.
§98.346(h & i) requires an indication of whether passive vents and/or passive flares (as defined in §98.6) are present.
§98.346(i) requires reporting of total annual LFG flow collected for destruction, average annual methane concentrations, monthly average LFG temperature and pressure (if not incorporated into internal calculations run by the monitoring equipment), and monthly average LFG moisture content (if needed).