Effect of rainfall on the diurnal variations of CH4, CO2, and N2O fluxes from a municipal solid waste landfill

Abstract

This paper presents the results of a field investigation into the effect of rainfall on the diurnal variations of CH4, CO2, and N2O fluxes at three different sites in a landfill. The three sites were all net sources of CH4, CO2, and N2O emissions ranging from 4.7–796mg CH4–Cm−2h−1, 131–811mg CO2–Cm−2h−1, and 90.6–2209μg N2O–Nm−2h−1. CH4 and N2O were generated by anaerobic digestion of waste and by nitrification and denitrification in the cover soil, respectively. Installation of an HDPE (High Density Polyethylene) membrane cover at landfill Site 1 was very effective in controlling CH4 emissions, and the CH4 fluxes at that site were 40–50 times lower than those at Site 2 and Site 3. For 36h following a rainfall event, both CH4 and N2O emissions were significantly correlated with moisture content of the cover soil at the two landfill sites without HDPE membrane cover (p<0.05). When CH4 and N2O fluxes were expressed as CO2-equivalent (CO2-e) emissions, CH4 emissions dominated in the three gases after rainfall (96.1% CO2-e emissions) and could be expressed by the following equation: YCH4=988.7+41.1X(soil moisture content)−32.2X(soil temperature) (R2=0.73, p<0.05).