Enhancement of the denitrification activity by exoelectrogens in single-chamber air cathode microbial fuel cells. (June 2019)

• Record Type: Journal Article
• Authors: Huang, Haobin; Cheng, Shaoan; Li, Fujian; Mao, Zhengzhong; Lin, Zhufan; Cen, Kefa
• Is Part Of: Chemosphere. Volume 225(2019)
• Page Start: 548
• Page End: 556
• Publication Date: 2019-06
• Subjects: Microbial fuel cells -- Single-chamber -- Denitrification -- Bioelectrochemical nitrite reduction -- Microbial community -- Stability; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2019.03.052
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Single-chamber microbial fuel cells (MFCs) can efficiently treat wastewater containing nitrate, probably because the interaction between exoelectrogens and denitrifying bacteria may enhance the denitrification activity of MFCs. In this study, the denitrification of nitrate with a wide range of concentrations was investigated by using single-chamber air cathode MFCs. The maximum average denitrification rate of the MFCs inoculated and operated under closed-circuit conditions (Group N-CC) was up to 12.2 ± 0.6 kg NO3 − -N m −3 d −1 at a high nitrate concentration of 2000 mg NO3 -N L −1, which was 74.3% higher than that of the MFCs inoculated and operated under open-circuit conditions and which was significantly higher than those of other MFC systems and many traditional bioreactors. The high denitrification activity of the MFCs of Group N-CC was attributed to the significant reduction of nitrite accumulation through the possible bioelectrochemical nitrite reduction by exoelectrogens that were only enriched at the anodes of the MFCs of Group N-CC. In addition, the MFCs of Group N-CC showed good stability (over 3.5 years) and low apparent activation energy (34.0 kJ mol −1 ) of the denitrification, indicating the good coexistence of exoelectrogens ( Geobacter ) and denitrifying bacteria ( Thauera ) with high performance on denitrification during the long-term operation. Graphical abstract: Image 1 Highlights: Denitrification of nitrate of up to 2000 mg NO3 − -N L −1 was studied in the MFCs. The MFCs achieved a nitrate removal rate up to 12.2 ± 0.6 kg NO3 − -N m −3 d −1 . Exoelectrogens reduced nitrite accumulation through bioelectrochemical reduction. Exoelectrogens promoted the enrichment of the denitrifying bacteria Thauera.