Continuous bioelectricity generation with simultaneous sulfide and organics removals in an anaerobic baffled stacking microbial fuel cell

• An improved anaerobic baffled stacking microbial fuel cell (ABSMFC) is built.
• Continuous bioelectricity is generated with sulfide and organics removals.
• Initial sulfide concentration and hydraulic retention time affect the performance.
• Molecular biology analysis confirms the interaction of the involved bacteria.
• Bacteria related to electricity generation, sulfur and organics removals are found.

The malodorous and toxic nature of sulfide governs its removal from wastewaters. An improved anaerobic baffled stacking microbial fuel cell (ABSMFC) was constructed for sulfide removal and energy recovery. With initial sulfide of 60 mg/L, chemical oxygen demand (COD) of 800 mg/L and hydraulic retention time (HRT) of 24 h, sulfide and COD removal efficiencies of 70.0% and 54.6% were achieved, respectively. The maximum voltage reached 2340 mV in series connection while the maximum current increased to 3.29 mA in parallel connection, with 1000 Ω external resistance. Initial sulfide concentration and HRT affected the performance of ABSMFC. Sulfide was mainly oxidized to elemental sulfur and sulfate. Molecular biology analysis indicated electrochemically activated bacteria, sulfur related bacteria and anaerobic fermentative bacteria interacted together. This study provides promising configurations of MFC to scale up for its actual applications in sulfide wastewater treatment.