Simultaneous treatment of chromium-containing wastewater and electricity generation using a plant cathode-sediment microbial fuel cell: investigation of associated mechanism and influencing factors

A novel plant cathode-sediment microbial fuel cell (P-SMFC) was constructed to treat Cr-containing wastewater, and the effects of the plants used, initial concentrations of Cr(VI) employed, and the external resistance on the treatment of wastewater and generation of electricity were investigated. The results showed that the system achieved the best performance when Acorus calamus was the cathode plant, the external resistance was 2000 Ω, and the initial Cr (VI) concentration of the overlying water of is 230 mg/L. A maximum power density of 40.16 mW/m 2 was reached, and Cr (VI) and COD removal efficiencies in the overlying water were 99.94% and 98.21%, respectively. The closed-circuit installation promoted the attachment of many microorganisms to the cathode, anode and sediment, increased species abundance, and reduced species diversity. The P-SMFC is inexpensive to construct, it consumes no energy, and it can generate bioelectricity; it thus has great application development value as a chromium-containing wastewater treatment method.