In-situ utilizing the produced electricity to regulate substrate conversion in denitrifying sulfide removal microbial fuel cells

A denitrifying sulfide removal microbial fuel cell, incorporated with a capacitor and run in an alternate charging and discharging mode, was developed to in-situ utilize the produced electricity. The switching interval, external resistance distribution and temperature were used to adjust substrates conversion via regulating electrode potentials. The switching interval of 10 min favored the formation of sulfur and gaseous nitrogen. Adjusting the external resistances via the constant anode potential method was a feasible measure for regulating the cathode potential and promoting nitrate reduction, achieving a total nitrogen removal rate of 16.5 +/- 0.8 g N/(m(3)d) and a gaseous nitrogen formation percent of 32.2 +/- 1.5%. 30 degrees C favored gaseous nitrogen formation while 10 degrees C and 40 degrees C benefited sulfur formation. In-situ utilization of the produced electricity shifted the microbial community structure. This work provided a novel approach to regulate the substrate conversion by in-situ utilizing the produced electricity.

Automated summary

A denitrifying sulfide removal microbial fuel cell was developed with a capacitor and operated in an alternate charging and discharging mode to utilize the produced electricity in-situ. Adjustment of electrode potentials and external resistance distribution was used to regulate substrate conversion, with 10-minute switching interval favoring sulfur and gaseous nitrogen formation. In-situ utilization of the produced electricity shifted microbial community structure and promoted nitrate reduction, achieving efficient total nitrogen removal and gaseous nitrogen formation.