Methane production in a bioelectrochemistry integrated anaerobic reactor with layered nickel foam electrodes

Towards the regulation and enhancement of inter-species electron transfer in sludge anaerobic digestion system, microbial electrolysis technology has become one of the effective ways to accelerate both fermentation and methanogenesis. In this study, the reactor performances and microbial activities related to biocathode formation are evaluated when the role of biocathode is regulated by series of layered cathodes. The results show the abundance of the cathodic methanogens decreased when enlarges the cathode area due to the lower current density. The biocathode evolution is directly related to the spatial methane distribution, which can further determine 25% increase of methane production rate compared to control without biocathode. Ultimately, the maximum methane production yield of 145.79 mL·d⁻¹ is achieved by the optimal cathode area with a current density of 5.3 mA/cm³. The spatially methanogens distribution in suspended sludge and electrodes regulated by the layered cathodes is regarded to be the key to increase methanogenesis.