Calcium nitrate treatment of oil sand tailings for improved densification and reduced greenhouse gas emissions
Date
2013-12-19
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Abstract
Canada contains one of the world’s largest bitumen reservoirs, the mining of which produces huge volumes of tailings stored in ponds where they persist as mature fine tailings (MFT) for decades, releasing up to 43,000 m3 d-1 biogenic methane from a single pond. MFT are typically treated with gypsum or polyacrylamide (PAM) to accelerate densification. Microbial reduction of sulfate and methane formation have been associated with improved densification through an unknown mechanism. Here, calcium nitrate treatment balanced with a carbon and energy source (molasses) was found to inhibit methanogenesis and reduced the number of syntrophs and methanogens present. Nitrous oxide emissions were found to be transient while the microbial cell counts increased suggesting biomass has a stronger influence on enhanced microbial densification than biogenic gas. Microbes associated with PAM treated tailings were found to remove amide groups and in the presence of oxygen create a nitrogen cycle while maintaining PAM flocs integrity.
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Microbiology
Citation
Brown, D. C. (2013). Calcium nitrate treatment of oil sand tailings for improved densification and reduced greenhouse gas emissions (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/25191