Municipal solid waste (MSW) landfills are the third largest anthropogenic source of methane (CH4) emissions in the United States. Part of the CH4 generated in landfills is converted to carbon dioxide (CO2) by CH4-oxidizing bacteria (MOB) present in the landfill cover soil, whose activity is controlled by various environmental factors including temperature. As landfill temperature fluctuates substantially due to seasonal variations and series of reactions during waste decomposition, which may affect the microbial activity and thus, the rates of CH4 oxidation. This study aims at analyzing the effect of temperature on CH4 oxidation potential and microbial community structure of methanotrophs in laboratory-based microcosm studies on landfill cover soil. Landfill cover soil samples were incubated at selectively two temperatures 23C and 50C, and rates of CH4 oxidation were measured, and microbial community structure was analyzed using shotgun metagenome sequencing. CH4 oxidation occurred at both temperatures in soil microcosm tests with highest activity at 23C. A corresponding shift in the soil microbiota was observed, with a transition from mesophilic to thermophilic methanotrophs with increased incubation temperature. The study shows that temperature is a critical factor affecting rates of CH4 oxidation in landfill cover soil, and the changing rates of CH4 oxidation are in part driven by shift in the methylotroph community.
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Identifying Active Methanotrophs and Mitigation of CH4 Emissions in Landfill Cover Soil
In the USA, municipal solid waste (MSW) landfills constitute one of the major anthropogenic sources of methane emissions. In the landfill cover soils employed at MSW landfills, aerobic methane-oxidizing bacteria (MOB) convert CH4 to CO2, thereby partially mitigating the CH4 emissions to the atmosphere. In this study, culture-dependent and culture-independent techniques were employed to evaluate methane oxidation capacity and to characterize the microbial community in landfill cover soil. Microcosms with synthetic landfill gas headspace were used to measure potential methane oxidation rates in landfill cover soil and in methanotrophs-enriched microbial consortia. The results demonstrate that the enriched landfill cover soil supported the growth of a diverse group of methanotrophic and methylotrophic microorganisms, and were dominated by Type I methanotrophs showing positive correlation with CH4
oxidation rates.
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- Award ID(s):
- 1724773
- NSF-PAR ID:
- 10104616
- Date Published:
- Journal Name:
- Proc. 8th International Congress on Environmental Geotechnics
- Volume:
- 2
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1007/978-981-13-2224-2_38
