Integration of MFC reduces CH4, N2O and NH3 emissions in batch-fed wetland systems

Hui Zhu; Tingting Niu; Brian Shutes; Xinyi Wang; Chunguang He; Shengnan Hou

doi:10.1016/j.watres.2022.119226

Integration of MFC reduces CH₄, N₂O and NH₃ emissions in batch-fed wetland systems

Water Res. 2022 Nov 1:226:119226. doi: 10.1016/j.watres.2022.119226. Epub 2022 Oct 10.

Authors

Hui Zhu¹, Tingting Niu², Brian Shutes³, Xinyi Wang⁴, Chunguang He⁵, Shengnan Hou⁴

Affiliations

¹ Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, PR China. Electronic address: zhuhui@iga.ac.cn.
² Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, PR China; Northeast Normal University, Changchun 130117, PR China.
³ Department of Natural Sciences, Middlesex University, Hendon, London NW4 4BT, UK.
⁴ Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, PR China.
⁵ Northeast Normal University, Changchun 130117, PR China.

PMID: 36257155
DOI: 10.1016/j.watres.2022.119226

Abstract

The combination of microbial fuel cells (MFCs) with constructed wetlands (CWs) for enhancing water purification efficiency and generating bioelectricity has attracted extensive attention. However, the other benefits of MFC-CWs are seldom reported, especially the potential for controlling gaseous emissions. In this study, we have quantitatively compared the pollutant removal efficiency and the emission of multiple gases between MFC-CWs and batch-fed wetland systems (BF CWs). MFC-CWs exhibited significantly (p < 0.01) higher COD, NH₄⁺-N, TN, and TP removal efficiencies and significantly (p < 0.01) lower global warming potential (GWP) than BF CWs. The integration of MFC decreased GWP by 23.88% due to the reduction of CH₄ and N₂O fluxes, whereas the CO₂ fluxes were slightly promoted. The quantitative PCR results indicate that the reduced N₂O fluxes in MFC-CWs were driven by the reduced transcription of the nosZ gene and enhanced the ratio of nosZ/(nirS + nirK); the reduced CH₄ fluxes were related to pomA and mcrA. Additionally, the NH₃ fluxes were reduced by 52.20% in MFC-CWs compared to BF CWs. The integration of MFC promoted the diversity of microbial community, especially Anaerolineaceae, Saprospiraceae and Clostridiacea. This study highlights a further benefit of MFC-CWs and provides a new strategy for simultaneously removing pollutants and abating multiple gas emissions in BF CWs.

Keywords: Ammonia volatilization; Constructed wetlands; Greenhouse gas emission; Microbial fuel cells.

MeSH terms

Bioelectric Energy Sources*
Methane / analysis
Nitrous Oxide / analysis
Water Purification*
Wetlands

Substances

Methane
Nitrous Oxide