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United States Department of Agriculture

Agricultural Research Service

Research Project: FARMING PRACTICES FOR THE NORTHERN CORN BELT TO PROTECT SOIL RESOURCES, SUPPORT BIOFUEL PRODUCTION AND REDUCE GLOBAL WARMING POTENTIAL Title: Seasonal greenhouse gas emissions (methane, carbon dioxide, nitrous oxide) from engineered landfills: Daily, intermediate, and final California cover soils

Authors
item Bogner, -
item Spokas, Kurt
item Chanton, J -

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 10, 2011
Publication Date: March 24, 2011
Repository URL: http://handle.nal.usda.gov/10113/59582
Citation: Bogner, Spokas, K.A., Chanton, J. 2011. Seasonal greenhouse gas emissions (methane, carbon dioxide, nitrous oxide) from engineered landfills: Daily, intermediate, and final California cover soils. Journal of Environmental Quality. 40(3):1010-1020.

Interpretive Summary: We measured the seasonal variability of methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O) emissions from various cover materials (e.g. fresh refuse, daily, intermediate, and final cover materials) at two California landfills. This was one of the first efforts examining the emissions from fresh refuse, and the averaged fluxes (g m-2 d-1) were 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). A negative surface emissions indicates that the cover materials coupled with the methanotrophic bacteria within the soil were sufficient to suppress all methane emissions and the soil cover is also oxidizing atmospheric methane, as has been observed in other ecosystems. Daily covers had the highest CO2 and N2O fluxes, indicating rapid onset of aerobic and semi-aerobic processes in recently-buried refuse (i.e. composting). 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. This research illustrates the high variability in surface emissions as a function of season, cover thickness and soil type. This research will contribute to improving annual greenhouse gas inventory guidelines where the soil processes need to be estimated for the assessment of the net emissions of methane to the atmosphere. Inclusion of these dynamic relationships coupled with appropriate modeling of soil temperature and moisture conditions will improve annual greenhouse gas inventory assessments

Technical Abstract: 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.

Last Modified: 12/26/2014