Enhancement of biohythane production from solid waste by co-digestion with palm oil mill effluent in two-stage thermophilic fermentation

Improvement of biohythane production from oil palm industry solid waste residues by co-digestion with palm oil mill effluent (POME) in two-stage thermophilic fermentation was investigated. A two-stage co-digestion of solid waste with POME has biohythane production of 26.5-34 m(3)/ton waste. The co-digestion of solid waste with POME increased biohythane production of 67-114% compared to digestion POME alone. Co-digestion of solid waste with POME enhanced hydrolysis constant (k(h)) from 0.07 to 0.113 to 0.120-0.223 d(-1). The hydrolysis constant (k(h)) of co-digestion was 10 times higher than the single digestion of solid waste. Clostridium sp. was predominated in the hydrogen stage, while Methanosphaera sp. was predominant in methane stage. The co digestion of solid waste with readily biodegradable organic matter (POME) could significantly increase biohythane production with achieving the significant cost reduction for pretreatment of solid wastes. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.