Bio-electrochemical treatment of mature fine tailings

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The accumulation of mature fine tailings in the Alberta oil-sands is a significant environmental challenge. Tailings ponds can release greenhouse gases such as methane formed due to biological degradation of organic contaminants. The tailings ponds also provide a potential pathway for toxic contaminants in to the environment. New solutions are thus needed to more rapidly remediate tailings ponds. Fine clay particles in the tailings are known to form a gel like network, so that settlement and consolidation of the solids can take many decades. Rapid remediation requires destabilization of the gel network, and typically this can be achieved by addition of chemicals, which can be high cost with potential environmental impacts. Recently electrokinetic remediation has been found to be effective, however the technology is difficult to scale and has relatively high energy consumption. This project involves investigation and evaluation of a novel bio-electrochemical treatment process for remediation of oil-sands tailings. Biofilms are cultivated on metal or carbon electrodes, using the micro-organisms that are naturally present in the tailings. By selection of suitable electrode materials, and control of the electrode potential, the bio-electrochemical treatment process can be tuned to consolidate and modify the physical, chemical, and biological characteristics of the tailings. Preliminary results performed in our laboratory have indicated that rapid consolidation of mature fine tailings can be achieved using this technology at very low energy consumption. In this project, we will investigate the impact of the bio-electrochemical treatment on the gaseous emissions, and the physical, chemical and biological characteristics of the tailings.