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Seasonal greenhouse gas emissions (methane, carbon dioxide, nitrous oxide) from engineered landfills: Daily, intermediate, and final California cover soils

Bogner, Jean, Spokas, Kurt A., Chanton, Jeffery P.
ARS USDA Submissions 2011
biogeochemical cycles, carbon dioxide, greenhouse gas emissions, landfills, methane, models, monitoring, nitrous oxide, organic wastes, oxidation, seasonal variation, soil ecology, soil water, solid wastes, temperature, windrow composting, California
We quantified the seasonal variability of CH4, CO2, and N2O emissions from fresh refuse and daily, intermediate, and final cover materials at two California landfills. Fresh refuse fluxes (g m-2 d-1) averaged CH4 0.053[+/-0.03], CO2 135[+/-117], and N2O 0.063[+/-0.059]. Average CH4 emissions across all cover types and wet/dry seasons ranged over more than 4 orders of magnitude (<0.01 to 100 g m-2 d-1) with most cover types, including both final covers, averaging <0.1 g m-2 d-1 with 10-40% of surface areas characterized by negative fluxes (uptake of atmospheric CH4). Daily covers had the highest CO2 and N2O fluxes, indicating rapid onset of aerobic and semi-aerobic processes in recently-buried refuse. Flux ranges from the more aerobic fresh refuse and daily covers can be systematically compared to published values for emissions from soil ecosystems and windrow composting of organic waste. For the intermediate and final cover materials, the variability in gaseous fluxes was attributable to cover thickness, properties, and seasonally-variable soil moisture and temperature at suboptimal conditions for CH4 oxidation. This study has emphasized the need for improved understanding of emissions from all cover types and the incorporation of seasonal as well as spatial variability in landfill monitoring designs and modeling frameworks.