Simultaneous sulfide removal, nitrogen removal and electricity generation in a coupled microbial fuel cell system

A coupled microbial fuel cell (MFC) system, consisting of a nitrifying sulfide removal MFC and a denitrifying sulfide removal MFC, was assembled to simultaneously treat ammonium and sulfide in wastewater. It provided a promising approach to recover electricity from wastewater containing sulfide and ammonium. Considering both substrate removal and electricity generation performance, the desirable feeding S/N molar ratio was deemed as 3 and the optimal temperature was found to be 30 °C. Under this condition, the coupled MFC achieved a sum coulomb production of 554.8 C/d, a total nitrogen removal efficiency of 58.7 ± 1.3% and a sulfur production percent of 27.4 ± 0.4-33.3 ± 0.9%. The introduction of nitrifiers and electroactive oxic microbes from the oxic-cathode chamber into the anoxic-cathode chamber favored nitrogen removal.