Enhancing the Treatment of Oil Sands Process Water through Bioremediation

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The oil sands industry in Alberta, Canada, currently produces over 1 million barrels of oil per day, drawing from the estimated 174 billion barrels of bitumen reserves in the area. These bitumen deposits are not readily available and must be extracted using large volumes of hot water. This in turn leads to large volumes of waste in the form of oil sands process-affected water and tailings. The Government of Alberta has instated a zero-discharge policy that requires these materials be recycled or stored on site and mandates that over time operators reclaim impacted sites back to their former self-sustaining ecosystems. One on-site storage and treatment option is end-pit lakes, which consist of fluid fine tailings capped with a layer of water. It is projected that the pollutants present in the pond will undergo natural attenuation over time. However, the use of end-pit lakes as a successful reclamation option has not yet been demonstrated at full field scale, and concerns regarding the flux of chemicals from sediments to overlying cap water and the effects of microbially mediated biogeochemical reactions remain. Chemical remediation options such as ozonation exist, but are too costly for large-scale use. Recent work in our lab has demonstrated that the addition of an extraction process waste product (petroleum coke) to oil sands process-affected water shows promise as an inexpensive way to effectively adsorb contaminants. However, petroleum coke is known to leach inorganic compounds (such as vanadium) upon contact with oil sands process-affected water, which would require subsequent treatment. One low-cost remediation option to treat oil sands waste is to utilize microorganisms that are able to degrade the appropriate contaminants. The primary objective of this Discovery Program is to 1) investigate the biogeochemical reactions occurring in end-pit lakes; and 2) identify a microbial consortium or individual organism(s) able to degrade contaminants and enhance the remediation of oil sands process-affected water prior to, or during, its enclosure in end-pit lakes. The short-term outcomes of this research will include 1) an increased understanding of contaminant flux and biogeochemistry within the end-pit lakes; 2) an assessment of the ability of the indigenous microbial community and isolated organisms to degrade contaminants of concern; and 3) an evaluation of the feasibility of using petroleum coke coupled with the bioremediation of vanadium to effectively treat oil sands process-affected water prior to enclosure in end-pit lakes. Long term, this research will enhance our knowledge of the natural bioremediation process and provide us with the tools to monitor and enhance both the effectiveness and the timeline of reclamation activities.