Similar evolution in 13CH4 and model-predicted relative rate of aceticlastic methanogenesis during mesophilic methanization of municipal solid wastes

摘要

Similar evolution was obtained for the stable carbon isotope signatures d13nCH4 and the model-npredicted relative rate of aceticlastic methanogenesis during mesophilic methanization ofnmunicipal solid wastes. In batch incubations, the importance of aceticlastic and hydrogenotrophicnmethanogenesis changes in time. Initially, hydrogenotrophic methanogenesis dominated, butnincreasing population of Methanosarcina sp. enhances aceticlastic methanogenesis. Later,nhydrogenotrophic methanogenesis intensified again. A mathematical model was developed tonevaluate the relative contribution of hydrogenotrophic and aceticlastic pathways of methanengeneration during mesophilic batch anaerobic biodegradation of the French and the ChinesenMunicipal Solid Wastes (FMSW and CMSW). Taking into account molecular biology analysisnreported earlier three groups of methanogens including strictly hydrogenotrophic methanogens,nstrictly aceticlastic methanogens (Methanosaeta sp.) and Methanosarcina sp., consuming bothnacetate and H2/H2CO3 were considered in the model. The total organic and inorganic carbonnconcentrations, methane production volume, methane and carbon dioxide partial pressuresnvalues were used for the model calibration and validation. Methane isotopic composition (d13nCH4)nevolution during the incubations was used to independently validate the model results. The modelndemonstrated that only the putrescible solid waste was totally converted to methane.