Effect of moisture of municipal biowaste on start-up and efficiency of mesophilic and thermophilic dry anaerobic digestion

Methane production from biowaste with 20-30% dry matter (DM) by box-type dry anaerobic digestion and contributing bacteria were determined for incubation at 20, 37 and 55 degrees C. The same digestion efficiency as for wet anaerobic digestion of biowaste was obtained for dry anaerobic digestion with 20% DM content at 20, 37 and 55 degrees C and with 25% DM content at 37 and 55 degrees C. No or only little methane was produced in dry anaerobic reactors with 30% DM at 20, 37 or 55 degrees C. Population densities in the 20-30% DM-containing biowaste reactors were similar although in mesophilic and thermophilic biowaste reactors with 30% DM content significantly less but phylogenetically more diverse archaea existed. Biogas production in the 20% and 25% DM assays was catalyzed by Methanosarcinales and Methanomicrobiales. In all assays Pelotomaculum and Syntrophobacter species were dominant propionate degraders. (C) 2014 Elsevier Ltd. All rights reserved.