Single-chamber microbial electrosynthesis reactor for nitrate reduction from waters with a low-electron donors’ concentration: from design and set-up to the optimal operating potential
Microbial electrosynthesis is a promising solution for removing nitrate from water with a low concentration of electron donors. Three single-chamber microbial electrosynthesis reactors were constructed and operated for almost 2 years. The single-chamber reactor design saves on construction costs, an...
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| Format: | Article |
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Frontiers Media S.A.
2022-08-01
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| Series: | Frontiers in Environmental Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fenvs.2022.938631/full |
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| author | Rauno Lust Jaak Nerut Sharvari S. Gadegaonkar Kuno Kasak Mikk Espenberg Triinu Visnapuu Ülo Mander |
| author_facet | Rauno Lust Jaak Nerut Sharvari S. Gadegaonkar Kuno Kasak Mikk Espenberg Triinu Visnapuu Ülo Mander |
| author_sort | Rauno Lust |
| collection | DOAJ |
| description | Microbial electrosynthesis is a promising solution for removing nitrate from water with a low concentration of electron donors. Three single-chamber microbial electrosynthesis reactors were constructed and operated for almost 2 years. The single-chamber reactor design saves on construction costs, and the pH of the solute is more stable than that in the case of a two-chamber reactor. Nitrate reduction started at the working electrode potential of −756 mV versus standard hydrogen electrode (SHE), and subsequently, the working electrode potential could be increased without hindering the process. The optimal potential was −656 mV versus SHE, where the highest Faradaic efficiency of 71% and the nitrate removal rate of 3.8 ± 1.2 mgN-NO3/(L×day) were registered. The abundances of nitrite reductase and nitrous oxide reductase genes were significantly higher on the working electrode compared to the counter electrode, indicating that the process was driven by denitrification. Therefore, a microbial electrosynthesis reactor was successfully applied to remove nitrate and can be utilized for purifying water when adding organic compounds as electron donors is not feasible, that is, groundwater. In addition, at the lower working electrode potentials, the dissimilatory nitrate reduction to ammonium was observed. |
| first_indexed | 2024-04-13T18:53:22Z |
| format | Article |
| id | doaj.art-1ee2aba813b64c0dba35901547f54959 |
| institution | Directory Open Access Journal |
| issn | 2296-665X |
| language | English |
| last_indexed | 2024-04-13T18:53:22Z |
| publishDate | 2022-08-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Environmental Science |
| spelling | doaj.art-1ee2aba813b64c0dba35901547f549592022-12-22T02:34:20ZengFrontiers Media S.A.Frontiers in Environmental Science2296-665X2022-08-011010.3389/fenvs.2022.938631938631Single-chamber microbial electrosynthesis reactor for nitrate reduction from waters with a low-electron donors’ concentration: from design and set-up to the optimal operating potentialRauno Lust0Jaak Nerut1Sharvari S. Gadegaonkar2Kuno Kasak3Mikk Espenberg4Triinu Visnapuu5Ülo Mander6Department of Geography, Institute of Ecology and Earth Sciences, University of Tartu, Tartu, EstoniaInstitute of Chemistry, University of Tartu, Tartu, EstoniaDepartment of Geography, Institute of Ecology and Earth Sciences, University of Tartu, Tartu, EstoniaDepartment of Geography, Institute of Ecology and Earth Sciences, University of Tartu, Tartu, EstoniaDepartment of Geography, Institute of Ecology and Earth Sciences, University of Tartu, Tartu, EstoniaDepartment of Genetics, Institute of Molecular and Cell Biology, University of Tartu, Tartu, EstoniaDepartment of Geography, Institute of Ecology and Earth Sciences, University of Tartu, Tartu, EstoniaMicrobial electrosynthesis is a promising solution for removing nitrate from water with a low concentration of electron donors. Three single-chamber microbial electrosynthesis reactors were constructed and operated for almost 2 years. The single-chamber reactor design saves on construction costs, and the pH of the solute is more stable than that in the case of a two-chamber reactor. Nitrate reduction started at the working electrode potential of −756 mV versus standard hydrogen electrode (SHE), and subsequently, the working electrode potential could be increased without hindering the process. The optimal potential was −656 mV versus SHE, where the highest Faradaic efficiency of 71% and the nitrate removal rate of 3.8 ± 1.2 mgN-NO3/(L×day) were registered. The abundances of nitrite reductase and nitrous oxide reductase genes were significantly higher on the working electrode compared to the counter electrode, indicating that the process was driven by denitrification. Therefore, a microbial electrosynthesis reactor was successfully applied to remove nitrate and can be utilized for purifying water when adding organic compounds as electron donors is not feasible, that is, groundwater. In addition, at the lower working electrode potentials, the dissimilatory nitrate reduction to ammonium was observed.https://www.frontiersin.org/articles/10.3389/fenvs.2022.938631/fullmicrobial electrochemical systembiocathodedenitrificationdissimilatory nitrate reduction to ammoniumchemolithoautotrophy |
| spellingShingle | Rauno Lust Jaak Nerut Sharvari S. Gadegaonkar Kuno Kasak Mikk Espenberg Triinu Visnapuu Ülo Mander Single-chamber microbial electrosynthesis reactor for nitrate reduction from waters with a low-electron donors’ concentration: from design and set-up to the optimal operating potential Frontiers in Environmental Science microbial electrochemical system biocathode denitrification dissimilatory nitrate reduction to ammonium chemolithoautotrophy |
| title | Single-chamber microbial electrosynthesis reactor for nitrate reduction from waters with a low-electron donors’ concentration: from design and set-up to the optimal operating potential |
| title_full | Single-chamber microbial electrosynthesis reactor for nitrate reduction from waters with a low-electron donors’ concentration: from design and set-up to the optimal operating potential |
| title_fullStr | Single-chamber microbial electrosynthesis reactor for nitrate reduction from waters with a low-electron donors’ concentration: from design and set-up to the optimal operating potential |
| title_full_unstemmed | Single-chamber microbial electrosynthesis reactor for nitrate reduction from waters with a low-electron donors’ concentration: from design and set-up to the optimal operating potential |
| title_short | Single-chamber microbial electrosynthesis reactor for nitrate reduction from waters with a low-electron donors’ concentration: from design and set-up to the optimal operating potential |
| title_sort | single chamber microbial electrosynthesis reactor for nitrate reduction from waters with a low electron donors concentration from design and set up to the optimal operating potential |
| topic | microbial electrochemical system biocathode denitrification dissimilatory nitrate reduction to ammonium chemolithoautotrophy |
| url | https://www.frontiersin.org/articles/10.3389/fenvs.2022.938631/full |
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