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Regional climate impact on landfill methane production and collection
Citation:
Krause, M. Regional climate impact on landfill methane production and collection. 2022 Intercontinental Landfill Research Symposium (ICLRS), Asheville, NC, September 19, 2021 - September 21, 2022.
Impact/Purpose:
In the US, landfill methane emissions are not direcly measured, they are modeled using various assumptions. This modeling approach requires the use of site-specific information as well as default parameter values. Research was performed to determine site-specific paramter values for dozens of closed landfills across the US. In most cases, the statisitical regression approach to derive site-specific values were greater than defaults. This suggests that waste is decaying faster than anticipated and that emissions during a landfill's active age are greater than previously thought.
Description:
An examination of the US Greenhouse Gas Reporting Program (GHGRP) database provided an opportunity for the largest evaluation to date of landfilled waste decomposition kinetics with respect to different US climate regimes. Five to eight years of annual methane collection data from 114 closed landfills located in 29 states were used to estimate site-specific waste decay rates (k) and methane collection potentials (Lc). These sites account for approximately 9% of all US landfills required to report GHG emissions to the US EPA annually. In typical gas generation modeling, the methane generation potential, L0, represents the ultimate amount of methane that would be generated per ton of waste disposed. This parameter is not able to be measured in field conditions, as shown in Figure 1a. While L0 is a function only of waste composition, Lc is a function of composition and operational conditions. Both Lc and k can be calculated with annual gas collection volumes provided in GHGRP, using inverse modeling, assuming gas collection is very close to the amount of gas being generated. This assumption is not valid for active landfills but is more appropriate for closed landfills where a cap has been installed and gas collection efficiency is at its highest.