High cost and low power output are two major obstacles to the application of microbial electrochemical systems (MES). Carbon-based material has been seen as the suitable anode for scale-up MES, but the inherent resistance of carbon-based anode material can be one of the main reasons leading to power loss. Through experimental verification, we found that integrating metal current collector into the anode and increasing its branches was an effective strategy to enhance the system performance in the case of a limited area of current collector. The experiment results showed the maximal power density of the system was enhanced with increasing branches of the current collector, and the anode with five branches could obtain higher maximal power density (1613.3±155.5 mW/m<sup>2</sup>), which was 1.36 times greater than anode with only one branch (1185.1±29.1 mW/m<sup>2</sup>), and even higher than those of previously reported high output systems with modified anodes. COMSOL software was first used in MES to reveal the enhancement mechanism and the simulation results corresponded well to the experiment. When using optimized “anode-collector” combination to treat domestic wastewater, the system could quickly generate voltage and the effluent met the grade A standard of COD for municipal wastewater treatment plants in China. Moreover, this strategy only needed approximately $0.061 of cost per milliwatt electricity generated, which is lower than commonly used carbon brush anode (0.08 $/mW). These results demonstrate that optimizing the “anode-collector” collection mode under an identical contact area between anode and collector is an effective strategy to enhance system performance with low cost and has promising potential for future practical application.

Enhanced microbial electrochemical systems performance by optimizing the “anode-collector” collection mode —from enhancement mechanism to construction strategy

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.