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Oxygen-reducing bidirectional microbial electrodes designed in real domestic wastewater
Morgane Hoareau1, Benjamin Erable1, Olivier Chapleur2
1Laboratoire de Génie Chimique, Université de Toulouse, CNRS, INP, UPS, Toulouse, France.
Bioresource Technology
|February 2, 2021
Summary
Microbial electrodes in wastewater efficiently oxidized organic matter and reduced oxygen, achieving high current densities. Diverse microbial communities in these electrodes enhance performance and robustness in bioelectrochemical systems.
Area of Science:
- Environmental Microbiology
- Electrochemistry
- Wastewater Treatment
Background:
- Microbial electrodes are crucial for bioelectrochemical systems, facilitating organic matter oxidation and oxygen reduction.
- Optimizing microbial electrode performance in domestic wastewater is essential for sustainable energy and treatment solutions.
Purpose of the Study:
- To design and evaluate microbial electrodes for alternating organic matter oxidation (anode) and oxygen reduction (cathode) in domestic wastewater.
- To investigate the impact of aeration phases and nitrogen use on microbial populations and electrode efficiency.
- To analyze the microbial diversity within internal and external biofilms and its correlation with electrode performance.
Main Methods:
- Development of microbial electrodes using domestic wastewater as the medium.
- Alternating anodic (organic oxidation) and cathodic (oxygen reduction) phases with controlled aeration.
- Analysis of microbial populations using techniques to assess diversity and abundance in biofilms.
- Measurement of current densities and evaluation of electrode efficiency under different conditions.
Main Results:
- Microbial electrodes achieved high current densities (up to 6.4 A m⁻²) without external substrate addition, driven by alternating aeration.
- Nitrogen use during anodic phases negatively impacted microbial populations and subsequent oxygen reduction capability compared to open-air conditions.
- Both internal and external biofilms exhibited high microbial diversity, comprising a mix of aerobic and anaerobic species, which correlated with electrode efficiency and robustness.
Conclusions:
- Alternating aeration phases significantly enhance the efficiency of microbial electrodes in domestic wastewater treatment.
- The observed robustness and high efficiency are attributed to the significant and diverse microbial communities within the electrodes.
- This study highlights the potential of diverse microbial consortia in bioelectrochemical systems for efficient wastewater treatment and energy recovery.
