2015 CSCE Annual Conference Regina - Building on our Growth Opportunities

2015 CSCE Annual Conference Regina - Building on our Growth Opportunities Conference

Application of Rhamnolipid and Microbial Activities for Improving the Sedimentation of Oil Sand Tailings

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Dr. Catherine Mulligan, Concordia University (Presenter)
Ms. Soroor Javan Roshtkhari , Concordia University

~~Densification of oil sand tailings deposited in the tailing ponds and water recovery are two major challenges issues in the oil sands industry. A small increase in the tailing settlement rate can improve tailing’s densification and significantly reduce water consumption and the volume of tailing ponds. Currently most industrial consolidation methods are based on clay particle flocculation using gypsum and polymeric flocculants. In this work, the potential of rhamnolipid as a flocculating agent and microbial activity for increasing the sedimentation rate of fine tailings was investigated. Sedimentation increased by increasing the rhamnolipid concentrations. According to the result of zeta potential and particle size distribution, rhamnolipid has increased sedimentation by improving the hydrophobicity of particles. Different concentrations of rhamnolipid with the two microbial strains isolated from weathered oil led to an increase in sedimentation (by a maximum factor of 3.04), the concentration of larger particles (by a maximum factor of 1.9), particle mean diameter (by a maximum factor of 2.11) and flocculation significantly. This could be probably due to the interaction of biosurfactant and high molecular weight organics with clay particles (through a bridging mechanism, and improving hydrophobicity) or due to the change in chemistry of pore water as a result of microbial metabolism. This work shows the potential of using rhamnolipid and microbial culture for increasing the oil sand tailing sedimentation in a potentially more environmental friendly and economical process. Further research is needed to determine the biosurfactant fate in the recycled water and the microbial role in sedimentation.