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Visualizing Methane-Cycling Microbial Dynamics in Coastal Wetlands
Published on: January 31, 2025
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CH4 control and associated microbial process from constructed wetland (CW) by microbial fuel cells (MFC)
Ke Zhang1, Xiangling Wu2, Hongbing Luo2
1School of Environment, Harbin Institute of Technology, Harbin, 150090, Heilongjiang, PR China; College of Civil Engineering, Sichuan Agricultural University, Dujiangyan, 611830, PR China.
Journal of Environmental Management
|February 25, 2020
Summary
This study introduces microbial fuel cells (MFCs) to control methane (CH4) emissions from constructed wetlands (CWs). Operating MFCs in a closed circuit significantly reduced CH4 fluxes and altered microbial communities, offering a green solution for climate change mitigation.
Area of Science:
- Environmental Science
- Environmental Engineering
- Microbiology
Background:
- Global warming is a growing concern, with methane (CH4) emissions from constructed wetlands (CWs) contributing to greenhouse gases.
- Microbial fuel cells (MFCs) present a potential technology for simultaneous wastewater treatment and energy generation.
Purpose of the Study:
- To investigate the efficacy of MFCs in reducing CH4 emissions from CWs.
- To evaluate the impact of MFC operation on bioelectricity generation, COD removal, and microbial community structure in CWs.
- To assess the influence of different plant species on MFC-CW performance.
Main Methods:
- Constructed wetlands integrated with microbial fuel cells (MFC-CWs) were operated under closed-circuit (CC) and open-circuit (OC) conditions.
- CH4 fluxes were measured, alongside bioelectricity generation and chemical oxygen demand (COD) removal rates.
- Quantitative real-time PCR (q-PCR) and sequencing analysis were employed to study microbial community structures and gene abundance (16S rRNA, pmoA, mcrA).
Main Results:
- Closed-circuit MFC-CWs exhibited significantly lower CH4 fluxes compared to open-circuit systems.
- The highest power density (0.27 W m⁻³) and lowest CH4 emissions (4.7 mg m⁻² h⁻¹) were achieved in the CC system.
- Plant species influenced CH4 emissions, with Typha orientalis showing higher emissions and Cyperus alternifolius reducing them by 45%.
- MFC operation altered microbial communities, enriching electrogenic bacteria (e.g., Geobacter) and suppressing methanogens (indicated by low mcrA gene abundance in anodes).
Conclusions:
- Operating MFCs in CWs is an effective green technique for mitigating CH4 emissions.
- The closed-circuit MFC configuration enhances bioelectricity generation and CH4 suppression.
- Plant selection plays a crucial role in optimizing MFC-CW performance for emission control and energy recovery.
- MFCs induce a competitive environment between electrogenic and methanogenic microbes, leading to reduced CH4 production.
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