MICROBIAL OXIDATION OF LANDFILL METHANE IN OPTIMIZED SOIL BIOCOVERS: COMPETITION OF RESPIRATION AND METHANE OXIDATION FOR OXYGEN AVAILABILITY

摘要

Microbial oxidation of CH4 in landfill cover soils is a known tool for the reduction of CH4 emission, The quantification of CH4 oxidation is of interest as a measure for the reduction of climate relevant emissions. Field methods include the gas push-pull test, the analysis of stable isotope fractionation, and a method that calculates CH4 oxidation efficiency from the shift in the CO2-CH4-ratio within the soil gas depth profile, or from the soil CH4 concentration and the CH4 and CO2 surface flux. In case of a known flux to the cover, a carbon mass balance can be established by measuring the CH4 and CO2 emission. For the latter three methods one limitation is the unknown quantity of CO2 stemming from soil respiration. Here, neglecting respiration as a CO2 source may lead to an overestimation of CH4 oxidation if respiratory CO2 is a significant CO2 source.