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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| Format: | Article |
| Language: | English |
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MDPI AG
2021-07-01
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| Series: | Microorganisms |
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| Online Access: | https://www.mdpi.com/2076-2607/9/7/1443 |
| _version_ | 1797526568865628160 |
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| author | Heidi L. Cossey Mian Nabeel Anwar Petr V. Kuznetsov Ania C. Ulrich |
| author_facet | Heidi L. Cossey Mian Nabeel Anwar Petr V. Kuznetsov Ania C. Ulrich |
| author_sort | Heidi L. Cossey |
| collection | DOAJ |
| 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 <i>Gammaproteobacteria, Desulfobulbia, and Anaerolineae</i>. 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. |
| first_indexed | 2024-03-10T09:31:11Z |
| format | Article |
| id | doaj.art-1b7d6f94215347c0afc74093c6322030 |
| institution | Directory Open Access Journal |
| issn | 2076-2607 |
| language | English |
| last_indexed | 2024-03-10T09:31:11Z |
| publishDate | 2021-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Microorganisms |
| spelling | doaj.art-1b7d6f94215347c0afc74093c63220302023-11-22T04:25:45ZengMDPI AGMicroorganisms2076-26072021-07-0197144310.3390/microorganisms9071443Biofilms for Turbidity Mitigation in Oil Sands End Pit LakesHeidi L. Cossey0Mian Nabeel Anwar1Petr V. Kuznetsov2Ania C. Ulrich3Department of Civil & Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, CanadaDepartment of Civil & Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, CanadaDepartment of Civil & Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, CanadaDepartment of Civil & Environmental Engineering, University of Alberta, Edmonton, AB T6G 1H9, CanadaEnd 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 <i>Gammaproteobacteria, Desulfobulbia, and Anaerolineae</i>. 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.https://www.mdpi.com/2076-2607/9/7/1443biofilmbiostabilizationturbidityend pit lakeBase Mine Lakeoil sands |
| spellingShingle | Heidi L. Cossey Mian Nabeel Anwar Petr V. Kuznetsov Ania C. Ulrich Biofilms for Turbidity Mitigation in Oil Sands End Pit Lakes Microorganisms biofilm biostabilization turbidity end pit lake Base Mine Lake oil sands |
| 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 | biofilm biostabilization turbidity end pit lake Base Mine Lake oil sands |
| url | https://www.mdpi.com/2076-2607/9/7/1443 |
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