Landfill bio-cover plays a significant role in methane reducing. It inhabits methane-oxidizing bacteria which reduce methane emissions to the atmosphere and supply carbon dioxide for photosynthesis. Full factorial 34 experimental design using simulation columns was conducted to investigate statistically the effects of mixed ratio, moisture content, nutrient addition and cover thickness on the CH4 oxidation efficiency through a landfill bio-cover sewage sludge modified by coal ash. The results from all experiment sets showed that all factors definitely influence methane oxidation ability. The CH4 oxidation efficiencies were different under different experimental and operating conditions. Synthesize the maximum CH4 oxidation efficiency and V(CH4), the optimal conditions was 1:1 mixed ratio of coal ash and sewage sludge, added 0.05 mL/g NMS nutrients to 400 mm thickness in landfill bio-cover which made moisture content of material reached 40%. The maximum CH4 oxidation efficiency and V(CH4) were 88.6% and 0.75 mmol/(kg•d) under the optimal conditions. Additionally, the decrease in the CH4 concentration and the increase in CO2 concentration in the headspace gas were clear indication that there was CH4 oxidation process.
