Empirical gas emission and oxidation measurement at cover soil of dumping site: example from Malaysia

Methane (CH4) is one of the most relevant greenhouse gases and it has a global warming potential 25 times greater than that of carbon dioxide (CO2), risking human health and the environment. Microbial CH4 oxidation in landfill cover soils may constitute a means of controlling CH4 emissions. The study was intended to quantify CH4 and CO2 emissions rates at the Sungai Sedu open dumping landfill during the dry season, characterize their spatial and temporal variations, and measure the CH4 oxidation associated with the landfill cover soil using a homemade static flux chamber. Concentrations of the gases were analyzed by a Micro-GC CP-4900. Two methods, kriging values and inverse distance weighting (IDW), were found almost identical. The findings of the proposed method show that the ratio of CH4 to CO2 emissions was 25.4 %, indicating higher CO2 emissions than CH4 emissions. Also, the average CH4 oxidation in the landfill cover soil was 52.5 %. The CH4 and CO2 emissions did not show fixed-pattern temporal variation based on daytime measurements. Statistically, a negative relationship was found between CH4 emissions and oxidation (R (2) = 0.46). It can be concluded that the variation in the CH4 oxidation was mainly attributed to the properties of the landfill cover soil.