Integration of submersible microbial fuel cell in anaerobic digestion for enhanced production of methane and current at varying glucose levels

A submersible microbial fuel cell (SMFC) was coupled with anaerobic digestion (AD) system to establish synergy for enhancing the electricity and methane production at different glucose concentration of 2, 4 and 10 g/l. High amount of stable current generation of 0.35 mA was obtained at 4 g/l, which was about 1.5 times higher than the SMFC-AD operated at 10 g/l glucose. Methane production and yield were enhanced by 69% and 28%, respectively in SMFC-AD in comparison with AD operation at 2 g/l. Maximum methane yield of 0.321-CH4/g COD was observed in SMFC-AD operation at 2 g/l, followed by 4 g/l (0.28 1-CH4/g COD) and 10 g/l (0.18 1-CH4/g COD). Furthermore, the SMFC-AD process increased COD removal and maintained proper pH of around 6.8-7.3 for efficient methane production. This study suggests that the SMFC-AD can achieve enhanced methane production compared to stand-alone AD with additional electricity generation. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.