Bioprocessing-Based Approach for Bitumen/Water/Fines Separation and Hydrocarbon Recovery from Oil Sands Tailings

Oil sands are a major source of oil, but their industrial processing generates tailings ponds that are an environmental hazard. The main concerns are mature fine tailings (MFT) composed of residual hydrocarbons, water, and fine clay. Tailings ponds include toxic contaminants such as heavy metals, and toxic organics including naphthenics. Naphthenic acids and polyaromatic hydrocarbons (PAHs) degrade very slowly and pose a long-term threat to surface and groundwater, as they can be transported in the MFT. Research into improved technologies that would enable densification and settling of the suspended particles is ongoing. In batch tests, BioTiger, a microbial consortium that can metabolize PAHs, demonstrated improved oil sands tailings settling from a Canadian tailings pond. Results also showed, depending on the timing of the measurements, lower suspended solids and turbidity. Elevated total organic carbon was observed in the first 48hours in the BioTiger-treated columns and then decreased in overlying water. Oil sands tailings mixed with BioTiger showed a two-fold reduction in suspended solids within 24hours as compared to abiotic controls. The tailings treated with BioTiger increased in microbial densities three orders of magnitude from 8.5 x 105 CFU/mL to 1.2 x 108 CFU/mL without any other carbon or energy source added, indicating metabolism of hydrocarbons and other available nutrients. Results demonstrated that bioaugmentation of BioTiger increased separation of organic carbon from particles in oil sands and enhanced settling with tailings with improved water quality. Journal style is for Abstract to be less than 200 words, and contain no citations to other sources; please edit as needed