A novel sulfur-driven autotrophic denitrification coupled with bio-cathode system for bioelectricity generation and groundwater remediation

Authors：Cheng, Jianping; Tang, Dai; Tang, Zhiguo^*; Guo, Jin

Source：WATER SCIENCE AND TECHNOLOGY, 2022, 86(5): 979-991.

DOI：10.2166/wst.2022.216

• bio-cathode microbial fuel cells
• bioelectricity generation
• sulfur-driven autotrophic denitrification

This study explored the feasibility of treating wastewater using sulfur-driven autotrophic denitrification (SAD) coupled with the bio-cathode of microbial fuel cell (MFC), focusing on simultaneous bioelectricity generation, denitrification, and desulphurization. A maximum output voltage of 360 mV was obtained with a power generation cycle of 25 h when simulated wastewater with 100.0 mg/L of each NO3--N and S2--S was employed as the influent in the SAD-BMFC. Compared with solo SAD or MFC, SAD-BMFC obtained a higher NO3--N removal rate (E-12 h = 87.7%, E-24 h = 100%), and less NO2--N accumulation. S2--S of the influent was almost completely removed, oxidized to S-0-S (88.6-90.2 mg/L) and SO42--S (9.8-11.4 mg/L). The reaction system achieved self-balance of acidity-alkalinity (pH 7.05-7.35). The SAD process was the main pathway for NO3--N removal (80.2%) and a smaller proportion of electrons came from the bio-cathode. This study effectively combined SAD with a bio-cathode system for simultaneous energy harvest and bio-enhanced remediation of groundwater contaminated by both NO3--N and S2--S.