Characterization And Mitigation Of Methane Emission At A Municipal Solid Waste Landfill Located In The North Of China

Municipal solid waste(MSW) landfills are one of main sources of anthropogenic methane emissions in China. Due to the low methane collection efficiency, a large amount of methane is fugitively released to the atmosphere from MSW landfills in China. Biocover technique is one of the key techniques for mitigating fugitive methane emission. However, because the performance of fugitive methane emission in Chinese landfills is unknown now, the use of biocover technique is limited. Thus, it is of great significance to study both the characters of fugitive methane emission in landfills and the feasibility of biocover technique for mitigating.Characteristics of methane oxidation and emission in field scale were determined at Landfill P by using static chamber approach, probe approach and stable isotope technique. Methane oxidation process could hardly occur in the operating surface. In autumn and winter, methane emission flux increased dramatically in both soil cover surface and operating surface. And the soil cover almost lost the methane oxidation capacity during this period.To mitigate the large amount of fugitive methane emissions from the operating surfacein autumn and winter, five types of materials were used as temporary covers. And the performance of these temporary covers on methane oxidation was evaluated. Methane oxidation hardly occurred in the blank cells. The mean value of fox were 56.1% in biochar-amended soil cells, 61.5% in aged refuse cells, 43.7% in waste compost cells, 34.7% in construction waste cells, and 64.3% in soil cells, respectively. The methane emission flux were 92.9 g/(m2·d) to 148.9 g/(m2·d) in biochar-amended soil cells, 7.2 g/(m2·d) to 96.9 g/(m2·d) in aged refuse cells, 69.4 g/(m2·d) to 129.1 g/(m2·d) in construction waste cells, 10.1 g/(m2·d) to 80.5 g/(m2·d) in waste compost cells, and 3.7 g/(m2·d) to 56.4 g/(m2·d) in soil cells. The methane oxidation capacity of construction waste and compost was poor.The effects of environmental factors(e.g., temperature, moisture content, and vegetation cover), nature of cover material(e.g., NH3-N, p H, and organic matter content), methane flux and cover depth on methane oxidation capacitywere studied. Except for the soil cover, the other four types of temporary covers had better adaptability to environmental factors(e.g., temperature, moisture content, and barometric pressure). High NH3-N concentration, low organic matter condition, and alkaline condition inhibited methane oxidation. Meanwhile, biochar-amended soil and aged refuse had better adaptability to methane influx. At more shallow depths, the fox of methaneincreased in all of the temporary covers, with the highest value occurring at the depth of 10 cm.Biochar-amended soil and aged refuse covers had excellent potentials for engineering applications in the operating surface. The methane reduced by the above two covers could account for approximately 1.0% or 0.9% of the total anthropogenic methane emission reported in China. When a temporary cover was applied, the effect of leachate and the quilt effect should be considered.