Energy Education

Water impacts of oil sands

Figure 1. Oil sands tailings ponds in Fort McMurray, Alberta. These ponds are used as a place to store used water from the oil sands mining process.[1]

One major environmental impact that comes from extraction in the oil sands is the water use. The water used in oil sands development is used in surface mining to separate the extracted oil sand into sand and bitumen components. Then, water is converted to steam in SAGD operations to separate the bitumen from the sand before it is extracted. The water used in the oil sands can be recycled, however, currently only small amounts of this water are actually returned to the natural cycle. Since the waste water is toxic and cannot simply be let free, the used water is stored in tailings ponds.[2] This increases the size of these ponds, further contributing to their negative environmental impacts. When a SAGD operation is used, old water is injected back into the ground instead of recycled for later use.[2]

Aside from how the water is dealt with once it is used, the initial volume required to extract bitumen is another potential issue. Operators estimated that 170 million cubic meters of water were used in oil sands operations in Canada in 2011, equivalent to the water use of 1.7 million Canadians in a year.[3][4] Essentially, this amounts to a required 2.4 barrels of fresh water required to extract and upgrade a single barrel of bitumen. In situ techniques require less, only needing 0.8 - 1.7 barrels.[3] Some argue that the use of this amount of water is not responsible, as it could provide water to local residents.

Ecosystems that rely on a water source, such as the ecosystem of the Athabasca River, can be at risk from water withdrawals since the majority of water used for mining in withdrawn from here.[4] This is the case in Alberta; the water withdrawal puts the availability of fish habitats at risk and can reduce the health of the ecosystem overall. Overall, the effects on the river are predicted to be dramatic if changes are not made. By 2050, if water use is not changed then the downstream flow of the Athabasca is expected to decrease by 30%.[4] This would drastically change the ecosystem of the river. A majority of the water that is taken is used in surface mining operations, with in situ extraction requiring slightly less water overall.

For Further Reading

References

  1. ↑ Wikimedia Commons. (June 9, 2015). Syncrude's Mildred Lake site, plant and tailings ponds [Online]. Available: http://en.wikipedia.org/wiki/Oil_sands#/media/File:Syncrude_mildred_lake_plant.jpg
  2. ↑ 2.0 2.1 Royal Society of Canada. (July 29, 2015). Environmental and Health Impacts of Canada’s Oil Sands Industry [Online]. Available: http://rsc-src.ca/sites/default/files/pdf/RSC%20Oil%20Sands%20Panel%20Main%20Report%20Oct%202012.pdf
  3. ↑ 3.0 3.1 Alberta Environment & Sustainable Resource Development. (June 19, 2015). Oil Sands Water Use [Online]. Available: http://osip.alberta.ca/map/
  4. ↑ 4.0 4.1 4.2 Pembina Institute. (June 19, 2015). Water [Online]. Available: http://www.pembina.org/oil-sands/os101/water
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