Flux measurements of greenhouse gases from an abandoned open dumping site of solid waste in Sri Lanka

Abstract

The investigation of greenhouse gas emission from a waste dumping site in Sri Lanka was conducted. The investigated site in this study is an abandoned waste dump site located at a hilly river bank in the Central Province of Sri Lanka (N 7º 09', E 80º 35'), consisting of two different sections with waste ages of around 0.5 year (New-section) and 7 years (Old-section). A simplified method for determination of methane gas flux using laser methane detector was considered to be effective to grasp the magnitude of methane flux. It was shown that the points those exhibited high value of methane gas flux also showed low EC-value compared with those of the other surround points. Furthermore, the low hardness of these points indicated that large amount of methane gas flux was caused by high permeability of surface as some stumps had been grown or as boundary between buried waste and ground line had been loosened. Measured fluxes for methane, carbon dioxide, and nitrous oxide in New-section ranged in <0.04-1800, 4.9-1800, and <0.0001-0.35 mL m-2 min-1, respectively. Little amount of methane gas was emitted from surface in Old-section. Relatively high fluxes of nitrous oxide were observed in some plots at middle and bottom for both sections, suggesting that nitrification was stimulated by aerobic condition due to the penetration of air from the slope of dumped waste.