Volume 53

Composite electrode plate for enhancing methanogenesis and microbial community performance in microbial electrolytic cell Qi Wu, Hongguang Zhu, Fanghui Pan, Fulu Lu, Yanan Liao

Abstract

Anaerobic digestion coupled with microbial electrolytic cell (AD-MEC) is a promising method for waste energy conversion. However, the technology is currently stuck in a bottleneck. The optimization of the electrode structure is a prospective way to improve the methane production efficiency of AD-MEC. In this study, a new composite electrode structure applied in AD-MEC is developed, consisting of stainless steel wire mesh and carbon felt connection combined to form an electrode, and the two electrodes are connected by an insulating cloth to form a composite electrode plate. The composite electrode plate was applied to the AD-MEC reactor and the traditional AD reactor for comparative experiments. The results show that, the biogas production of the AD-MEC reactor increased by 76.6% compared to the control reactor at a voltage of 0.7V. In addition, the start-up time of the AD-MEC reactor was significantly reduced, the average daily methane content increased by 13.5%, and the cumulative methane production increased by 105.6%. Meanwhile, there are certain differences in microbial community richness and diversity between AD-MEC reactor and control reactor, which is considered to be one of the reasons for the improvement of methane production efficiency. The increase of biogas production and methane content demonstrates that the structural optimization of stainless steel wire mesh carbon felt composite electrode is an effective method to improve AD-MEC efficiency, waste treatment and energy recovery.

Keywords Composite electrode plate; Stainless steel wire mesh; Carbon felt; Microbial electrolytic cell; Methanogenesis