Sulfate-containing wastewater treatment, electricity generation and community structure in an anaerobic fluidized bed–microbial fuel cell

Abstract

A large amount of wastewater containing high concentration sulfate is discharged from the industrial production process. Wastewater with a high concentration of sulfate and low chemical oxygen 2– demand (COD)/SO4 ratio is difficult to biodegrade. An anaerobic fluidized bed–microbial fuel cell (AFB–MFC) system was constructed to illustrate the effects of high sulfate concentration and low 2– 2– COD/SO4 ratio on anodic system performance. Results showed that, with increased SO4 concentration from 900 to 7,200 mg/L and COD from 6,000 to 2,400 mg/L, COD, NH4+ 2– –N and SO4 removal efficiency decreased from 95.9% to 52.5%, 43.3% to 28.5%, 81.2% to 18.6%, respectively. When 2– SO4 was 3,600 mg/L, the maximum output voltage of 704.6 mV and a power density of 24.8 mW/m2 were achieved, respectively. Meanwhile, sludge characteristics analyses revealed a high concentration 2– of SO4 addition had little effect on microbial sedimentation performance of the AFB–MFC system. Genomic sequencing analysis of anode bioparticles revealed that increasing sulfate altered Levilinea from 2.12% to 16.3%, which co-worked with Methanolinea while suppressing Methanosaeta thereby adapting to substrate adjustment. The studies would be conducive to the development of AFB–MFC applications in the treatment of high sulfate concentration wastewater.