Accelerated Dewatering and Detoxification of Oil Sands Tailings Using a Biological Amendment

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  • Accelerating the dewatering of oil sands tailings is a crucial challenge to the oil sands industry. Fresh tailings (15–20% by weight
    solids) and mature tailings (30–35% by weight solids) dewater slowly over a period of decades or centuries, and have resulted in the accumulation of 1,075 Mm3 of tailings in tailings ponds, the equivalent of 430,000 Olympic-size swimming pools. UltraZyme Hydrocarbon
    Powder (UltraZyme), a proprietary biological amendment of microbes, enzymes, and organic carrier developed by Cypher Environmental
    Ltd., was tested for its ability to accelerate dewatering and improve expressed pore water quality in three types of tailings. The effects of
    varying temperature, nitrogen addition, initial solids content, and UltraZyme dosage were also investigated. A 30% increase of solids content
    could be achieved in 112 days in all three tailings sources using 1.0 g=L of UltraZyme without physical mixing. Increasing the temperature to
    55°C yielded similar results in only 14 days. High UltraZyme dosages and low initial solids contents had the most positive impact on dewatering rates, and UltraZyme addition caused detoxification of expressed pore water (toxicity unit < 1, by Microtox bioassay) and improved
    dissolved organic carbon (DOC) (27% removal for MFT-D1 and 16% removal for MFT-D2) and naphthenic acids (NAs) (38–46% removal
    for MFT-Mix). UltraZyme was unable to degrade bitumen, but was capable of reducing bitumen-derived toxicity.

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    Article (Published)
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    Attribution-NonCommercial 4.0 International