Sulfate produced during anaerobic reduction limits the activity of methanogens but it is not reflected in the Intergovernmental Panel on Climate Change (IPCC) methodology for estimating CH4 emissions. In this study, CH4 emissions from the Sudokwon landfill site were estimated by adopting a methane correction factor, which was determined through the relationship between the COD/sulfate ratio and CH4 generation. Although the gas originating from the Sudokwon landfill site has not produced any environmental problems in recent years due to gas collection and soil cover maintenance activities, CH4 emissions estimated by the IPCC methodology indicated that only 60% of the CH4 was recovered and the remainder was emitted into the atmosphere, suggesting a potential environmental problem. Accordingly, CH4 estimates determined according to IPCC methodology must be modified by adopting the methane correction factor and considering the effect of sulfate concentration.

The 2nd landfill of Sudokwon landfill site has been collecting landfill gas flowing into vertical wells using the vacuum generated by blowers. The vacuum applied to the wells enables the landfill gas within the collection boundary to be collected and the air in the atmosphere to be penetrated through landfill cover soil, as well. In this study, we tried to investigate the impact of active landfill gas collection with vertical wells on landfill aeration. The pressure changes and the compositions of landfill gas, measured at the wells and 4 bore holes made in the landfill for this study, showed the air penetrates the landfill cover and inflows into the vertical wells. The concentration of nitrogen in the landfill gas collected from the 2nd landfill site has been increased to 14 ~ 15% as of February 2013, indicating 18 ~ 19% of the air is being included in the landfill gas.