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Nitrate and nitrite reduction activity of activated sludge microcosm in a highly alkaline environment with solid cementitious material

Durban, Nadège and Sonois-Mazars, Vanessa and Albina, Pierre and Bertron, Alexandra and Albrecht, Achim and Robinet, Jean-Charles and Erable, Benjamin Nitrate and nitrite reduction activity of activated sludge microcosm in a highly alkaline environment with solid cementitious material. (2020) International Biodeterioration & Biodegradation, 151. 104971. ISSN 0964-8305

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Official URL: https://doi.org/10.1016/j.ibiod.2020.104971

Abstract

Denitrification is a major biological process contributing to nitrate and nitrite reduction. However, this process remains poorly understood at alkaline pH although such conditions can be encountered in natural (e.g. soda lakes) or industrial environments (e.g. geological waste repositories with cementitious materials). To investigate the nitrate reduction (NR) rate for pH > 9.5 in a cementitious environment, several batch reactors were implemented, with cement leachate or with hardened cement paste (HCP). In the experiments carried out with cement leachate, NR dropped from 0.72 mM/h at pH 9.5 to 0.17 mM/h at pH > 11, while the concentration of nitrite increased. The NR was inhibited at pH close to 12, as was the nitrite reduction at pH above 11. In the reactor containing HCP, the NR rate was 0.75 mM/h at pH close to 10. Calcite precipitated on the HCP surface. Epifluorescence microscopy observations coupled with DNA labelling suggested the presence of microorganisms attached to the HCP surface. This was confirmed by biological growth coupled with NR activity after the transfer of the HCP into a new medium, considered to be sterile. The bacterial community analysis showed that the highly selective culture conditions led to the selection of two species: Halomonas sp. and a species known for its versatile metabolism and ability to form biofilms, i.e. Thauera sp.

Item Type:Article
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Agence Nationale pour la Gestion des Déchets Radioactifs - ANDRA (FRANCE)
French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Université de Toulouse > Institut National des Sciences Appliquées de Toulouse - INSA (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
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Deposited On:28 Jun 2021 08:21

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