Methane Oxidation in Landfill Cover Soils

Microbial methane oxidation in landfill cover soil is a very effective approach for reducing emissions from landfills. Oxidation of methane may be enhanced by the application of materials present on site, such as yard waste or compost. Engineers require a method to quantify methane oxidation in different types of covers. In this paper we will present a simple, effective stable isotope technique for the evaluation of cover soil methane oxidation. The approach exploits systematic variations in the ratio of ¹³C/¹²C in CH₄ prior to and following exposure to methane oxidizing microbes in the soil. The action of the bacteria increases this ratio, due to their preference for utilizing ¹²CH₄ rather than ¹³CH₄. The shift in the ratio following oxidation is proportional to the amount of CH₄ oxidized.