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Biofilms for Turbidity Mitigation in Oil Sands End Pit Lakes

End pit lakes (EPLs) have been proposed as a method of reclaiming oil sands fluid fine tailings (FFT), which consist primarily of process-affected water and clay- and silt-sized particles. Base Mine Lake (BML) is the first full-scale demonstration EPL and contains thick deposits of FFT capped with w...

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Autores principales: Cossey, Heidi L., Anwar, Mian Nabeel, Kuznetsov, Petr V., Ulrich, Ania C.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8307862/
https://www.ncbi.nlm.nih.gov/pubmed/34361879
http://dx.doi.org/10.3390/microorganisms9071443
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author Cossey, Heidi L.
Anwar, Mian Nabeel
Kuznetsov, Petr V.
Ulrich, Ania C.
author_facet Cossey, Heidi L.
Anwar, Mian Nabeel
Kuznetsov, Petr V.
Ulrich, Ania C.
author_sort Cossey, Heidi L.
collection PubMed
description End pit lakes (EPLs) have been proposed as a method of reclaiming oil sands fluid fine tailings (FFT), which consist primarily of process-affected water and clay- and silt-sized particles. Base Mine Lake (BML) is the first full-scale demonstration EPL and contains thick deposits of FFT capped with water. Because of the fine-grained nature of FFT, turbidity generation and mitigation in BML are issues that may be detrimental to the development of an aquatic ecosystem in the water cap. Laboratory mixing experiments were conducted to investigate the effect of mudline biofilms made up of microbial communities indigenous to FFT on mitigating turbidity in EPLs. Four mixing speeds were tested (80, 120, 160, and 200 rpm), all of which are above the threshold velocity required to initiate erosion of FFT in BML. These mixing speeds were selected to evaluate (i) the effectiveness of biofilms in mitigating turbidity and (ii) the mixing speed required to ‘break’ the biofilms. The impact of biofilm age (10 weeks versus 20 weeks old) on turbidity mitigation was also evaluated. Diverse microbial communities in the biofilms included photoautotrophs, namely cyanobacteria and Chlorophyta (green algae), as well as a number of heterotrophs such as Gammaproteobacteria, Desulfobulbia, and Anaerolineae. Biofilms reduced surface water turbidity by up to 99%, depending on the biofilm age and mixing speed. Lifting and layering in the older biofilms resulted in weaker attachment to the FFT; as such, younger biofilms performed better than older biofilms. However, older biofilms still reduced turbidity by 69% to 95%, depending on the mixing speed. These results indicate that biostabilization is a promising mechanism for turbidity mitigation in EPLs.
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spelling pubmed-83078622021-07-25 Biofilms for Turbidity Mitigation in Oil Sands End Pit Lakes Cossey, Heidi L. Anwar, Mian Nabeel Kuznetsov, Petr V. Ulrich, Ania C. Microorganisms Article End pit lakes (EPLs) have been proposed as a method of reclaiming oil sands fluid fine tailings (FFT), which consist primarily of process-affected water and clay- and silt-sized particles. Base Mine Lake (BML) is the first full-scale demonstration EPL and contains thick deposits of FFT capped with water. Because of the fine-grained nature of FFT, turbidity generation and mitigation in BML are issues that may be detrimental to the development of an aquatic ecosystem in the water cap. Laboratory mixing experiments were conducted to investigate the effect of mudline biofilms made up of microbial communities indigenous to FFT on mitigating turbidity in EPLs. Four mixing speeds were tested (80, 120, 160, and 200 rpm), all of which are above the threshold velocity required to initiate erosion of FFT in BML. These mixing speeds were selected to evaluate (i) the effectiveness of biofilms in mitigating turbidity and (ii) the mixing speed required to ‘break’ the biofilms. The impact of biofilm age (10 weeks versus 20 weeks old) on turbidity mitigation was also evaluated. Diverse microbial communities in the biofilms included photoautotrophs, namely cyanobacteria and Chlorophyta (green algae), as well as a number of heterotrophs such as Gammaproteobacteria, Desulfobulbia, and Anaerolineae. Biofilms reduced surface water turbidity by up to 99%, depending on the biofilm age and mixing speed. Lifting and layering in the older biofilms resulted in weaker attachment to the FFT; as such, younger biofilms performed better than older biofilms. However, older biofilms still reduced turbidity by 69% to 95%, depending on the mixing speed. These results indicate that biostabilization is a promising mechanism for turbidity mitigation in EPLs. MDPI 2021-07-04 /pmc/articles/PMC8307862/ /pubmed/34361879 http://dx.doi.org/10.3390/microorganisms9071443 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Cossey, Heidi L.
Anwar, Mian Nabeel
Kuznetsov, Petr V.
Ulrich, Ania C.
Biofilms for Turbidity Mitigation in Oil Sands End Pit Lakes
title Biofilms for Turbidity Mitigation in Oil Sands End Pit Lakes
title_full Biofilms for Turbidity Mitigation in Oil Sands End Pit Lakes
title_fullStr Biofilms for Turbidity Mitigation in Oil Sands End Pit Lakes
title_full_unstemmed Biofilms for Turbidity Mitigation in Oil Sands End Pit Lakes
title_short Biofilms for Turbidity Mitigation in Oil Sands End Pit Lakes
title_sort biofilms for turbidity mitigation in oil sands end pit lakes
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8307862/
https://www.ncbi.nlm.nih.gov/pubmed/34361879
http://dx.doi.org/10.3390/microorganisms9071443
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