Simultaneous electricity generation and nitrogen and carbon removal in single-chamber microbial fuel cell for high-salinity wastewater treatment

Simultaneous power generation and nitrogen and carbon removal were achieved in a single-chamber microbial fuel cell for high-salinity mustard tuber wastewater treatment. The results showed that mustard tuber wastewater, which was a self-buffered electrolyte, could be used as a suitable fuel for providing a maximum power density of 8.3 +/- 0.2 W/m(3) at a C/N ratio of 7. Furthermore, the removal efficiencies of chemical oxygen demand, ammonia, and total nitrogen were 86.09%, 96.55%, and 96.17%, respectively, at a C/N ratio of 4. Batch experiments showed that simultaneous nitrification and denitrification occurred in the single-chamber microbial fuel cell. A microbial community analysis revealed that heterotrophic nitrifiers (including Thauera, Paracoccus, Arcobacter, and Flavobacterium), heterotrophic denitrifiers (including Thauera, Vitellibacter, Caldithrix, Candidatus_Competibacter, Castellaniella, and Rheinheimera), and sulfur autotrophic denitrifiers (including Sedimenticola, Stappia, Sulfurovum, and Thioalbus) were enriched for nitrogen removal. Moreover, sulfate reduction considerably promoted carbon removal but lowered the nitrogen removal efficiency. These findings will aid in developing methods for mustard tuber wastewater efficient treatment. (C) 2020 Elsevier Ltd. All rights reserved.