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Determination of As-Discarded Methane Potential in Residential and Commercial Municipal Solid Waste
Citation:
Townsend, T., G. Chickering, S. Thorneloe, AND M. Krause. Determination of As-Discarded Methane Potential in Residential and Commercial Municipal Solid Waste. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-18/087, 2018.
Impact/Purpose:
Methane emissions from U.S. landfills are a major contributor of global methane emissions contributing to increasing carbon content in the atmosphere. This study is unique in that it looked total waste being discarded - including fines - rather than preselecting components to evaluate. The results confirm the range of potential values based on sampling four different locations and support the current value recommended for use in emission inventories. The results also reflect the range of values that can exist reflecting the uncertainties of estimating landfill methane emissions.
Description:
The objective of this research was to measure methane potential (Lo) in commercial and residential waste samples obtained from waste collection vehicles at the point of disposal. Previously reported Lo values span a wide range including estimates substantially lower than the current US EPA default values (100 m3 CH4/Mg MSW) for use in emission inventories. Most previous estimates were developed from waste composition studies and default component Lo values or best-fit analysis based on measured landfill gas collection and default collection efficiencies. This research took a waste compositional approach paired with individually measured methane generation potentials for each sample collected. This study also addressed the fines fraction of MSW which is omitted in previous studies. On average 43% of biogenic carbon evolved to carbon in CH4 or CO2 among all biodegradable waste under anaerobic conditions. These findings showed residential and commercial waste produced an average Lo lower than existing default value but higher than estimates in some recent studies. Several loads of waste in this study produced methane in excess of the current AP-42 value.