Effect of nitrate concentration on power generation and nitrogen removal in microbial fuel cell

ABSTRACT

Microbial fuel cell (MFC) technology with decarbonization and denitrification is considered to be advantageous in treating wastewater with a low carbon-to-nitrogen ratio. In this study, MFC was treated with different concentrations of nitrate-nitrogen. The MFC technology revealed significant treatment advantages when compared to both abiotic electrode treatment and microbial treatment only. The best treatment effect was recorded when the MFC's nitrate-nitrogen (${\mathrm{N}\mathrm{O}}_3^{-}-\mathrm{N}$) concentration was 414 mg/L. The running of the MFC system showed that it produced a stable output voltage of up to 0.17 V within 160 h. It showed a power density of up to 40.18 mW/m², 1.58 times M1 (138 mg/L, 25.49 mW/m²), and 4.48 times non-biological electrode. The removal rate of ${\mathrm{N}\mathrm{O}}_3^{-}-\mathrm{N}$ was 97.48%, but the lack of anode electron supply resulted in the incomplete reduction of nitrate-nitrogen and accumulation of nitritenitrogen. Nitrate-nitrogen concentration in the study had no significant impact on microbial population diversity. However, the relative abundance of Proteobacteria increased from 47.3% to 65.4% when ${\mathrm{N}\mathrm{O}}_3^{-}-\mathrm{N}$ concentration increased from 138 to 414 mg/L. Burkholderiales, Hydrogenophilales, and Rhodocyclales were the main denitrifying bacteria. These results demonstrate promise in supporting the development of microbial cathode denitrification.

KEYWORDS:

• Microbial fuel cell
• biological cathode
• nitrogenous wastewater

Acknowledgements

The authors acknowledge Xiaocong Liu and Tong Zuo for their support in the laboratory.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Xiaofan Ma

Xiaofan Ma (1998), female, from Urumqi, Xinjiang, is a student at the School of Environment and Engineering, Qingdao University of Science and Technology.

Jun Zhou

Jun Zhou (1982), male, from Qingdao, Shandong Province, is an Associate Professor in the School of Environment and Engineering, Qingdao University of Science and Technology.

Qinwei Jia

Qinwei Jia (1997), male, from Jinan, Shandong Province, is a student at the School of Environment and Engineering, Qingdao University of Science and Technology.

Yuhang Zhao

Yuhang Zhao (1998), male, from Zhengzhou, Henan Province, is a student at the School of Environment and Engineering, Qingdao University of Science and Technology.

Luyu Wang

Luyu Wang (1998), male, from Shangqiu, Henan Province, is a student at the School of Environment and Engineering, Qingdao University of Science and Technology.

Lei Gong

Lei Gong (1976), male, from Qingdao, Shandong Province, is an associate professor in the School of Environment and Engineering at Qingdao University of Science and Technology.

Jin Wang

Jin Wang (1996), female, from Heze, Shandong Province, is a student at the School of Environment and Engineering, Qingdao University of Science and Technology.