Extracellular polysaccharides (EPS) are suspicious one of the causes in reduction of methane oxidation in landfill cover soils. This study aims to investigate effect of aeration at surface landfill cover soil on methane oxidation rate in relating to EPS production. The dual simulated cover soil columns were separately observed for soil and gas monitoring for one-year operation to obtain information of soil and gas changes in the same time. First set was the control without soil surface aeration. Second one was operated by supplying various soil surface aeration rates of 44, 88 and 440 mL/min. The results show that aeration could provide more oxygen available in deeper soil (20 ～ 60cm of depth). Because of aeration, methane oxidation could be occurring in deeper soil (40 ～ 50cm) in the aerated column but insignificant rate while the control could not. However, methane oxidation was found mainly only the upper soil column (1～30 cm) in both conditions. It appeared that surface aeration in low rates (44～88ml/min) did not promote methane oxidation. Inversely, it gave negative effect on MOR resulting in the lower total MOR in aerated column (350g/(m~2 · d)) as compared to the control (400g/(m~2 · d)). In case of high aeration rate, aeration rate of 440ml/min gradually increased the MOR at 1 ～ 15 cm depth resulting in increase of total MOR equal to the control (400g/(m~2 · d)). The EPS content had trended to increase with the operational time, but trended to reduce with soil depths in both conditions. Moreover, increasing EPS content directly related to the soil surface aeration which the maximum EPS (4. 8mgC/g soil) was found when aeration increased to 440ml/min. The EPS/ biomass ratio (1.3) was highest at soil surface where the methane and oxygen ratio was the lowest in the column with maximum aeration rate.
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