Use of algae for recovery and utilization of oil sands naphthenic acids

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Alberta's oil sands are the second largest oil reserves in the world, and in 2005 represented 39% of Canada's total crude oil production. The extraction of usable crude and equivalents from the tar sands, however, requires considerable effort and energy input, and current extraction techniques produce a large volume of tailings water as a byproduct. The most abundant contaminants found within tailings water are naphthenic acids (NAs), present at approximately 20-120 mg/L. The concentrations of NAs found in tailings water preclude the direct release of tailings water back to natural aquatic systems, resulting in accumulation of very large amounts of tailing water in ponds and artificial lakes surrounding upgrader facilities. We propose to investigate the use of algal species for extraction of NAs from tailings water. Algal species can accumulate, adsorb, and to a lesser degree metabolize NAs. The algae and accumulated NAs can then be filtered from tailings water, providing an effective means to remediate NA contaminated water. The filtered algae can be utilized for biodiesel production and as a soil additive for land reclamation efforts, providing both economic and environmental benefits. Algae oil can be produced from algae in a similar manner to production of vegetable oil, then esterified to produce biodiesel. The esterification reactions used to convert triglycerides and fatty acids to biodiesel can also esterify NAs, converting them into a non-acidic form similar to biodiesel. Residual organic material after oil extraction can be used as a soil additive to be used in land reclamation after oil sands mining, so minimal waste products are produced. Additionally, significant amounts of CO2 may be recovered from the flue gases emitted oil sands facilities, reducing net CO2 emissions. The long term goals of a remediation system such as this would be multi-functional- tailings water can be sufficiently treated for release or re-use, CO2 would be sequestered by algae, biodiesel and organic soil additive would be produced from algae, and NAs would be converted to methyl esters suitable as diesel fuel. The goals of this proposal are to study the feasibility of the various components involved in the remediation process described above.