Environmental Impacts and Challenges

Fluid Tailings Dewatering

Fluid tailings have exerted great pressure on the oil sands industry. In 2020 the volume of the fluid tailings has doubled the amount of 2008. The liability of the fluid tailings in Alberta was estimated around $130 billion in 2018. To comply with the fluid tailings volume profile set by Directive 085, only a small window of a few years is provided to prevent the total volume of the fluid tailings exceeding the ceiling of 1.7 billion cubic meters.

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R&D Milestones

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• In 2017, the fluid tailings dewatering R&D was initiated

• In 2022, the WAGD in-situ dewatering technology was showcased on the 7th International Oil Sands Conference

• In 2023, the lab-scale Direct Sand Capping (DSC) was demonstrated

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Diluted Bitumen Spill Response

Diluted bitumen (dilbit) is a unique oil of Canada and can be transported to all over the world. One environmental impact is that once it is spilled to an aquatic environment it may attach solids in water to form a sunken oil which may increase the cleanup cost dramatically. For example, in the 2010 Kalamazoo dilbit spill cleanup, Enbridge has spent more than one billion dollars in three years  rather than the original estimation of 5 Million dollars.

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One challenge for the cleanup of spilled dilbit is the time-consuming locating process of the sunken oil, even using the most efficient “poling” technique. The second challenge is the dewatering of the huge amount of water and sand together with the sunken oil. The third challenge is that only small amount of vacuumed sucked liquid from the thin slick dilbit collection is oil. The fourth challenge is that the cleanup waste of an oil spill could be up to 10 folds of the spill and lime hardening is a common process before the waste can be land-filled. 

Operations Waste Decontamination

Paraffin froth treatment (PFT) is a relatively new technology, which can pass over the upgrading process and directly produce a clean final product for the market. The rejected PFT tailings from the tailing solvent recovery unit contains about 75% water, 20% minerals, 5% asphaltenes and maltenes, and <0.1% solvents.

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Comparing with conventional fluid tailings, the PFT tailings contain more water and organic contaminants and less solids. This might be more challenging for the tailing reclamation and there might be a lot of unknown gaps over how they influence the legacy tailings if they are directly discharged to the existing tailing ponds.

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