Sulfate reducing bacteria-based wastewater treatment system integrated with sulfide fuel cell for simultaneous wastewater treatment and electricity generation

Abstract

This study aimed to design a sulfate-reducing bacteria (SRB)-based wastewater treatment system (SWTS) integrated with a sulfide fuel cell (SFC) as an alternative to the energy-intensive aerobic wastewater treatment process. The result showed that the COD/sulfate ratio and hydraulic retention time (HRT) were two important parameters in a SWTS. The highest COD and sulfate removal efficiency rates were at a HRT of 4 h at a COD/sulfate ratio of 0.67, reaching 83 ± 0.2% and 84 ± 0.4% with sulfate removal rates of 4.087 ± 32 mg SO42−/d, respectively. A microbial analysis revealed that the dominance of nine OTUs belonging to SRB closely affected the high sulfate removal efficiency in the SWTS. At the HRT of 8 h, voltage of 0.02 V and a power density level of 130 mW/m2 were obtained with sulfide removal efficiency of 99 ± 0.5%. These results overall demonstrate that SRB can serve as a green and effective route for wastewater treatment.