The role of microbial electrolysis cell in urban wastewater treatment: integration options, challenges, and prospects

Katuri, Krishna P.; Ali, Muhammad; Saikaly, Pascal E.

doi:10.1016/j.copbio.2019.03.007

Cited by 115 publications

(40 citation statements)

References 61 publications

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“…Pure hydrogen can be used as a valuable resource for fuel and manufacturing other chemicals. Hydrogen has a higher energy content than methane, encouraging the development of hydrogen production over methane [95] the high gross heating value of hydrogen is 39.4 kWh/kg whereas for methane it is 13.8-15.4 kWh/kg. However, hydrogen production adds complexity to the system design and operation.…”

Section: Analysis Of Hydrogen or Methane Production And Its Implicatimentioning

confidence: 99%

Microbial Electrolysis Cells for Decentralised Wastewater Treatment: The Next Steps

Fudge

Bulmer²,

Bowman³

et al. 2021

Water

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Traditional wastewater treatment methods have become aged and inefficient, meaning alternative methods are essential to protect the environment and ensure water and energy security worldwide. The use of microbial electrolysis cells (MEC) for wastewater treatment provides an innovative alternative, working towards circular wastewater treatment for energy production. This study evaluates the factors hindering industrial adoption of this technology and proposes the next steps for further research and development. Existing pilot-scale investigations are studied to critically assess the main limitations, focusing on the electrode material, feedstock, system design and inoculation and what steps need to be taken for industrial adoption of the technology. It was found that high strength influents lead to an increase in energy production, improving economic viability; however, large variations in waste streams indicated that a homogenous solution to wastewater treatment is unlikely with changes to the MEC system specific to different waste streams. The current capital cost of implementing MECs is high and reducing the cost of the electrodes should be a priority. Previous pilot-scale studies have predominantly used carbon-based materials. Significant reductions in relative performance are observed when electrodes increase in size. Inoculation time was found to be a significant barrier to quick operational performance. Economic analysis of the technology indicated that MECs offer an attractive option for wastewater treatment, namely greater energy production and improved treatment efficiency. However, a significant reduction in capital cost is necessary to make this economically viable. MEC based systems should offer improvements in system reliability, reduced downtime, improved treatment rates and improved energy return. Discussion of the merits of H2 or CH4 production indicates that an initial focus on methane production could provide a stepping-stone in the adoption of this technology while the hydrogen market matures.

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Section: Analysis Of Hydrogen or Methane Production And Its Implicatimentioning

confidence: 99%

Microbial Electrolysis Cells for Decentralised Wastewater Treatment: The Next Steps

Fudge

Bulmer²,

Bowman³

et al. 2021

Water

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“…Oxidation of water and organics are the best-known anode reactions used in MES [7][8][9], while using ammonium as anode p&e source has, to the best of our knowledge, not yet been investigated. Microbial electrosynthesis (MES) reactor setup with two chambers: Anode chamber is fed any anaerobic digestion (AD) feed for biogas production (i.e., wastewater treatment plant sludge) for ammonium oxidation, and the liquid is cycled through the cathode chamber for biomethane production.…”

Section: Anode : Electrochemical Processmentioning

confidence: 99%

Section: Anode:electrochemical Processmentioning

confidence: 99%

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Ammonium as a Carbon-Free Electron and Proton Source in Microbial Electrosynthesis Processes

et al. 2020

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Biogas upgrading to biomethane with microbial electrosynthesis (MES) is receiving much attention due to increasing biomethane demands and surplus renewable energy. Research has demonstrated the feasibility of MES to increase methane yield by reducing CO2 in anaerobic digestion (AD). Such CO2 reduction occurs at the cathode and requires the supply of both protons and electrons. The most studied sources of protons and electrons are oxidation of organic substances and water, generated at the anode. These anodic reactions, however, also imply the production of CO2 and O2, respectively, both with negative implications for the AD process. A source of protons and electrons without CO2 and O2 as by-products would be beneficial for MES-enhanced biomethane production. This opinion article discusses the possibility of ammonium to serve as a sustainable proton and electron source.

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“…The organic matters are oxidized in MEC anode via exoelectrogens to release the protons and electrons, and H 2 is subsequently generated in MEC cathode with a little applied voltages (E ap ), compared with water electrolysis (theoretically calculated to be 0.11 V vs. 1.21 V). Moreover, the E ap can be supplied by kinds of sustainable energy sources, such as solar panels, wind energy, and low-grade heat [6] . MEC was recognized as a green wastewater treatment technology because it can [7] : (i) utilize a wide source of substrates in the wastewaters; (ii) produce three times higher H 2 than that produced by traditional dark fermentation, which could meet the market of H 2 fuel with an annual growth rate of 6.3% and reduce the cost of wastewater treatment to some extent; (iii) reduce solid discharge and further reduce handling costs of the sludge; (iv) limit the release of harmful odors and mitigate climate change.…”

Section: Introductionmentioning

confidence: 99%

Treatment of recalcitrant wastewater and hydrogen production via microbial electrolysis cells

Shen

Zhao

et al. 2019

International Journal of Agricultural and Biological Engineering

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A large amount of real complex wastewaters are generated every year, which leads to a great environmental burden. Various treatment technologies were deployed to remove the contaminants in the wastewaters. However, these actual wastewaters have not been sufficiently treated due to their complex properties, high-concentration organics, incomplete utilization of hard-biodegradable substrates, the high energy input required, etc. Recently, microbial electrolysis cells (MECs), a great potential technology, has emerged for various wastewater treatment, because not only do they demonstrate satisfactory performance during wastewater treatment, but they also generate renewable H 2 as a clean energy carrier. Unlike previous reviews, this review introduced the characteristics of every complicated wastewater, and focused on analyzing and summarizing MEC development for wastewater treatment. The performances of MECs were systematically reviewed in terms of organics removal, H 2 production, Columbic efficiency, and energy efficiency. MEC performances for treating actual complex wastewaters and producing H 2 can be optimized through operation parameters, electrode materials, catalyst materials, etc. In addition, the challenges and opportunities including complexity of wastewaters, instability of H 2 production, robust microorganisms, effect of membrane on two-chamber MEC, and integration of MEC with other treatment processes were deeply discussed. Except for the technical feasibility, both environmental feasibility and economic feasibility also need to meet social requirements. This review can indeed provide a basis for high-efficiency treatment and practical commercial applications of recalcitrant wastewaters via MECs in the future.

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The role of microbial electrolysis cell in urban wastewater treatment: integration options, challenges, and prospects

Cited by 115 publications

References 61 publications

Microbial Electrolysis Cells for Decentralised Wastewater Treatment: The Next Steps

Microbial Electrolysis Cells for Decentralised Wastewater Treatment: The Next Steps

Ammonium as a Carbon-Free Electron and Proton Source in Microbial Electrosynthesis Processes

Treatment of recalcitrant wastewater and hydrogen production via microbial electrolysis cells

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