Bioelectrochemical Sulfate Reduction Enhanced Nitrogen Removal From Industrial Wastewater Containing Ammonia And Sulfate

Low organic carbon-to-nitrogen ratio and existing sulfate (SO42-) in industrial wastewater limited nitrogen removal. Coupling SO42- reduction with sulfide autotrophic denitrification provides a novel strategy. Herein, bioelectrochemical sulfate reduction was coupled with heterotrophic sulfate reduction to drive sulfide autotrophic denitrification. In this coupled system, total nitrogen (TN) removal efficiency was increased from similar to 25% to similar to 85% by inputting -45 mA electricity. With the help of supplying electrons to denitrification through SO42- reduction, coulomb efficiency was improved to 61.5%. Also, bioelectrochemical sulfate reduction could improve sulfur recovery and thus increase TN removal efficiency. Furthermore, through tuning turnover numbers of SO42-, high TN removal efficiency can be obtained at various concentrations of SO42-. Moreover, main functional bacteria in this system were identified. Finally, similar to 75% TN removal efficiency was achieved with real wastewater in this system. Overall, this work offered a new approach for efficient nitrogen removal from industrial wastewater containing SO42-.