Effects of Temperature, Moisture Content, and Fertilizer Addition on Biological Methane Oxidation in Landfill Cover Soils

Patterns of methane (CH4) oxidation were investigated under various combinations of environmental factors including temperature, moisture content, and fertilizer addition (as an additional nutrient source) in two types of existing landfill cover soils. In all the experimental runs, CH4 and oxygen concentrations decreased with time, while carbon dioxide concentration increased suggesting that biological CH4 oxidation was taking place. The highest CH4 oxidation rates (6.4–12.3μgCH4h−1gdrysoil−1) were achieved at 35°C. The lowest oxidation rates (3.3–4.7μgCH4h−1gdrysoil−1) were obtained for experiments conducted at 5°C without adding the fertilizer. For both types of soil, without adding fertilizer, the soil with 20% moisture content (MC) showed consistently higher oxidation rates compared to soil samples containing 25 or 30% MC, for different operating temperatures. Adding the fertilizer as the nutrient source to the two soils samples with 30% moisture content resulted in enhanced CH4 oxidation rates in a range of 44–145% at tested temperatures in the range between 5 and 35°C.