Regular articlePower recovery coupled with sulfide and nitrate removal in separate chambers using a microbial fuel cell

•Sulfide removal in anode and nitrate removal in cathode was accomplished.•Bicarbonate was a suitable buffer for this denitrifying sulfide removal MFC.•The suitable HRT and temperature for this MFC were found to be 2.77 h and 30 °C.•A power density of 2.80 ± 0.05 W/m3 NC was obtained in this MFC.•More than 71.9% of sulfide was converted to sulfate in the anode chamber.

A novel denitrifying sulfide removal microbial fuel cell (MFC), using sulfide and nitrate separately as the anodic electron donor and the cathodic electron acceptor, was explored to recover power coupled with pollutants removal. Power recovery coupled with sulfide and nitrate removal in this MFC was achieved under different buffers, hydraulic retention times (HRTs) and temperatures. Bicarbonate was deemed as a suitable alternative buffer to phosphate in this MFC, obtaining comparable power recovery and pollutant removal loadings but without potential secondary pollution. Shortening HRT from 5.54 h to 2.27 h or increasing temperature from 20 °C to 30 °C favored both power recovery and pollutants removal. The suitable HRT and temperature for this MFC were found to be 2.77 h and 30 °C, achieving a power density of 2.80 ± 0.05 W/m3 NC, a sulfide removal loading of 1.07 ± 0.03 kg S/(m3 NCd), and a nitrate removal loading of 14.4 ± 0.3 g N/(m3 NCd). Shortening HRT and lowering temperature would be beneficial to suppress sulfate formation, but more than 71.9% of sulfide was oxidized to sulfate in current study.

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