CH4 control and associated microbial process from constructed wetland (CW) by microbial fuel cells (MFC)

Ke Zhang; Xiangling Wu; Hongbing Luo; Xiangkun Li; Wei Chen; Jia Chen; You Mo; Wei Wang

doi:10.1016/j.jenvman.2020.110071

CH₄ control and associated microbial process from constructed wetland (CW) by microbial fuel cells (MFC)

J Environ Manage. 2020 Apr 15:260:110071. doi: 10.1016/j.jenvman.2020.110071. Epub 2020 Jan 25.

Authors

Ke Zhang¹, Xiangling Wu², Hongbing Luo², Xiangkun Li³, Wei Chen², Jia Chen², You Mo², Wei Wang⁴

Affiliations

¹ School of Environment, Harbin Institute of Technology, Harbin, 150090, Heilongjiang, PR China; College of Civil Engineering, Sichuan Agricultural University, Dujiangyan, 611830, PR China. Electronic address: zhangke@sicau.edu.cn.
² College of Civil Engineering, Sichuan Agricultural University, Dujiangyan, 611830, PR China.
³ School of Environment, Harbin Institute of Technology, Harbin, 150090, Heilongjiang, PR China. Electronic address: hitxiangkunli@163.com.
⁴ School of Environment, Harbin Institute of Technology, Harbin, 150090, Heilongjiang, PR China.

PMID: 32090814
DOI: 10.1016/j.jenvman.2020.110071

Abstract

Global warming is becoming more severe. We here proposed an innovative green technique aimed at reducing the CH₄ emissions from constructed wetlands (CWs) in which CH₄ is controlled by microbial fuel cells (MFCs). The results of our work indicated that CH₄ emissions from CWs could be controlled by operating MFC. The CH₄ fluxes significantly decreased in the MFC-CW (close circuit CC) compared with the control MFC-CW (open circuit OC). The bioelectricity generation and COD removal rates also differed in the two systems. The highest power density (0.27 W m^-3) and the lowest CH₄ emissions (4.7 mg m^-2 h^-1) were observed in the CC system. The plants' effects on the performance of the MFC-CWs were also investigated. The plant species had a profound impact on the CH₄ emissions and electricity production in MFC-CWs. The greatest CH₄ flux (9.5 mg m^-2 h^-1) was observed from the MFC-CW planted with Typha orientalis, while the CH₄ emissions from the MFC-CW planted with Cyperus alternifolius were reduced by 45%. Additional microbial processes were investigated. Quantitative real-time PCR (q-PCR) analysis indicated that the gene abundance of eubacterial 16 S rRNA, particulate methane monooxygenase (pmoA), and methyl coenzyme M reductase (mcrA) significantly differed for the control CW and MFC-CWs planted with different plants. In the CC systems, the mcrA genes in the anode were low, while the pmoA genes in the cathode were high. The operation of MFCs in CWs changed the exoelectrogenic and methanogenic community structures. Sequencing analysis indicated that phylotypes related to Geobacter, Bacteroides, and Desulfovibrio were specifically enriched in the CC systems. The results demonstrated that the operation of MFCs in the CWs resulted in the competition between the electrogenes and methanogenes, which resulted in distinctive microbial populations and biochemical processes that suppressed the CH₄ emissions from the CWs.

Keywords: CH(4) control; Constructed wetland (CW); Microbial fuel cell (MFC); Microbial mechanisms; Plant species.

MeSH terms

Bioelectric Energy Sources*
Electricity
Electrodes
Wastewater
Wetlands

Substances

Waste Water