Short-term kinetic response of enhanced methane oxidation in landfill cover soils to environmental factors

This paper aims at a better understanding of methane oxidation under conditions that are representative of landfill cover soils. The kinetics of methane oxidation were studied in landfill cover soils that had been exposed to high methane mixing ratios. This was done in batch experiments, under various environmental conditions. V-max increased exponentially with temperature in the range 5-35 degreesC, with a Q(10) value of 2.8. K-m increased approximately linearly in this range from 1.2 muM to 7 muM. Consequently, the influence of temperature on methane consumption was more pronounced at high concentrations than at low concentrations. The inhibition by ammonium of methane consumption was much stronger after 6-7 months of exposure to high methane mixing ratios than after 5-7 weeks of exposure, indicating that there was a shift of dominating methanotrophic species in soils after long exposure times. Additions of nitrifying sludge or compost to soils initially inhibited methane oxidation, followed by a stimulation after a few days.