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

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 demand (COD)/SO42- 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 COD/SO42- ratio on anodic system performance. Results showed that, with increased SO(4)(2- )concentration from 900 to 7,200 mg/L and COD from 6,000 to 2,400 mg/L, COD, NH4+-N and SO42- removal efficiency decreased from 95.9% to 52.5%, 43.3% to 28.5%, 81.2% to 18.6%, respectively. When SO42- was 3,600 mg/L, the maximum output voltage of 704.6 mV and a power density of 24.8 mW/m(2) were achieved, respectively. Meanwhile, sludge characteristics analyses revealed a high concentration of SO42- 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.