Microbial separator allied biocathode supports simultaneous nitrification and denitrification for nitrogen removal in microbial electrochemical system

Abstract

Microbial separator (MS) allied biocathode was considered as one promising construction mode for pilot-scale microbial electrochemical system (MES). Instead of traditional ion exchange membrane, the microbial separator provided more potential for nitrogen metabolism due to its hydraulic permeable performance. In microbial separator installed biocathode MES, nitrogen removal efficiency, functional bacteria composition, and nitrogen metabolism routes were systemically investigated. Nitrogen removal tests suggested that the nitrogen removal was restricted by the ammonia oxidation reaction in cathode chamber. The PICRUSt2 functional genes prediction proved that simultaneous nitrification and denitrification reaction (SNDR) was dominant pathway for the nitrogen metabolism. The microbial composition analysis provided direct evidences that microbial separator compensated the simultaneous nitrification and denitrification.