Dynamics Research On Anaerobic Oxidation Of MSW Landfill Methane

Municipal solid waste (MSW) Landfill is one of the major sources of themethane emissions to the atmosphere. The Landfill Gas Collection (LFG) can reducethe several magnitudes of the methane, but the cost is high. By the indigenousmethanotrophic bacteria，bio-cover can be a cost effective manufacturing method forlow-calorific emissions from MSW landfills. By comparing the two methods, Aerobicoxidation of methane (AOM) of MSW is fairly mature, meanwhile, the anaerobicmethane oxidation is not mentioned frequently. The objective of this study was toquantify the dynamics of AOM in the cover soils of MSW.Firstly, CH4fluxes were explored during the whole year around by usingGC-static chamber method. The test sites were distinguished by a diverse range of thelandfill ages, waste type, LFG, etc.Secondly, proved the existence of AOM in the deep of the soil where wasanaerobic through4different kinds of landfill cover soils.At last, anaerobic batch experiments were carried out to analyze the roles ofenvironmental factors, sulphate, nitrate and heavy metals on the landfill gas emissionsin four different soils, and this article colud draw some conclusions as following:1、The MSW landfills were different for the the variations of waste andenvironmental factors during the four seasons. In consequence of this distinction, themethane emissions were changeable, therefore, a continuous monitoring should beused on MWS landfills.2、The decreasing concentration of methane in the cover soils, which was notcaused by the dilution effect of air, could prove the impossibility of methane oxidationunder anaerobic conditions and show the carbon transform relationship betweenmethane and carbon dioxide.3、AOM was effected by the initial concentration of methane, similarly,controlled by environmental factors. The optimum conditions for the AOM werefound that initial concentration of CH4was10%, soil size was a part of0.25~2mm,moisture content was20%and the culture temperature was35℃.4、Both nitrate and sulfate had an effect on the rate of CH4oxidation. Nitrate wasbeneficial to nitrification and denitrification. With the sulfate addition could improvethe amount of bacteria group and activity of sulfate in the soils. But as the sulfateincreased, the depressant action on nitrification and denitrification reaction would appear. Mostly, the oxidation of methane, as well as the form of carbon dioxide andnitrous through the7-d incubation, which showed that early stage of the reaction wasa key to control AOM.5、Heavy metals would affect anaerobic methane oxidation and the extentdepended on both the kinds of heavy metals and the type of tested soils. Aged refusesoils had strong capacity of heavy metals for the high organic content, accumulationof ammonia oxidizing bacteria. Meanwhile, the leading role of CH4oxidizing bacteriain aged refuse were different from other soil samples.