Methane oxidation in landfill waste biocover soil: Kinetics and sensitivity to ambient conditions

Abstract

Waste biocover soil was investigated as an alternative in regions with a shortage of landfill cover soil. In the work, effects of the composition, ambient conditions and nitrogen stress on CH 4 oxidation in waste biocover soil were studied. The results showed that the optimal composition of waste biocover soil as a landfill cover material for CH 4 oxidation was original pH value, 45% moisture and a particle size of ⩽4 mm. CH 4 oxidation rate increased rapidly over a CH 4 concentration range of 0.01–10% (v/v), and kept stable at CH 4 concentrations of 10–30% (v/v). The Michaelis–Menten model showed a good fit for the kinetic of CH 4 oxidation in landfill waste biocover soil with a maximum of 9.03 μmol/g d.w./h. The average Q 10 was 10.6 in the batch experiments. A level of 5% of oxygen concentration was enough to sustain the activity of methanotrophs community structure in waste biocover soil. Waste biocover soil had low baseline concentrations of NH 4 + -N and NO 3 - -N. Ammonia volatilization from landfills and nitrification in landfill waste biocover soils might stimulate CH 4 consumption at concentrations below 600 mg/kg. However, the contents of NH 4 + -N and NO 3 - -N above 1200 mg/kg would inhibit CH 4 oxidation in landfill waste biocover soil. Compared with NO 3 - -N, NH 4 + -N had a greater stimulating action as nutrient at lower concentrations and inhibitory effect at higher concentrations on CH 4 oxidation in landfill waste biocover soil.