Methane Oxidation Potential of Landfill Cover Soil and Its Influencing Factors

An indoor batch incubation experiment was carried out to explore methane oxidation potentials of four kinds of typical landfill cover soils aged sandy cover soil (ASCS), new sandy cover soil (NSCS), aged clayey cover soil (ACCS) and new clayey cover soil (NCCS) and effects of moisture content and temperature on methane oxidation rate (MOR) of ASCS and ACCS. Results show that in terms of MOR, the four types of cover soils followed an order of ACCS ＞ASCS ＞NCCS ＞NSCS; MOR of the aged cover soils was dramatically affected by both moisture content and temperature and ascended and then descended with rising water content and temperature; MOR was the highest when moisture content and temperature was at 25% and in the range of 20-30°C,respectively. Besides, addition of sawdust (SD) and cow dung (CD) mixture with mixing ratio varying between 4:0 and 3:1, increased MOR significantly in NSCS and NCCS; MORs peaked in NSCS and NCCS added with SD and CD mixture 1:3 in ratio, being about 1.63 and 1.41 times as high as that in the control, respectively. It is, therefore, recommended that in designing landfill cover, SD and CD mixture be added to increase CH₄ oxidation potential of new cover soils.