Application of nano-scale transition metal carbides as accelerants in anaerobic digestion

Four types of nano-scale transition metal carbides (HfC, SiC, TiC, and WC), used as accelerants in anaerobic digestion (AD) with cattle manure, were investigated through batch experiments under mesophilic conditions (37 +/- 1 degrees C). The AD system with four carbide accelerants showed a higher biogas yield (463-499 mL/g TS), chemical oxygen demand (COD) degradation rate (58.62-78.90%) and total Kjeldahl nitrogen (TKN) concentrations (905.0-1077.0 mg/L) as compared with control check (CK, 294 mL/g TS, 46.99%, 290 mg/L). All of the digestate samples from the AD systems using four carbide accelerants showed not only higher degradation of organic compounds during thermal analysis, but also stronger fertilizer values. The use of transition metal compounds (TMCs) as accelerants in AD can efficiently improve the conversion of waste resources into biogas and fertilizers, which can potentially open new avenues for the use of TMCs in upcoming research on biomass energy. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.