Cleaning up oilsands exploration

Materials World magazine
1 Nov 2009

Scientists in the USA have developed two polymers, to help clean up the toxic waste left behind by oilsands mining.

The organic polymers (exact composition is confidential) adhere to the waste materials in tailings ponds that cover over 50 square miles of the Alberta, Canada.

The ponds are a mixture of sand, clay, water and traces of oil and the polymers attach to the clay and sand. The clay then binds with the sand to form a hybrid material, with the intervening polymers providing attraction between the two inorganic components. The hybrid material forms an anchor and drags the two components to the bottom of the ponds. The wastewater with traces of oil can then be recycled to process more oilsands, and the solids are returned to the ground.

David Soane, of inventors Soane Energy in Boston, USA, explains that current methods of dealing with tailings are through Thickened Tail (TT), which is equipment intensive and Composite Tail (CT), with gypsum which returns clarified water that is contaminated with calcium ions (this negatively affects bitumen extraction). ‘Neither method generates stackable solids rapidly and both rely on the processed waste to be contained in the tailings ponds, which can lead to contamination’.

He hopes that his firm polymers will remove the use of containment tailings ponds. He says, ‘The process for solid separation from clarified water can be either simple settling or continuous filtration.

Dominic Thomas, Team Leader of Drilling [Fluids & Environment] at British Gas Advance says, the process described has some merit. ‘One issue stands out - putting the solids back where they came from. In the UK on and off shore, putting material back where it came is not an option without significant extra engineering and compliance with legislation. Each phase of the process is regulated separately.

‘To do this onshore in the UK would be impossible in the simple manner described because of the prevailing waste legislation. Therefore this process would have to show that it complied with Canadian legislation to have any chance of success.’

Soane Energy hopes that a new Directive from the Energy Resources Conservation Board (ERCB) of Canada, which will require oil producers to do more to clean up their tailings ponds, will generate more interest in their research.

The oilsands of Alberta, represent the second biggest deposit of oil in the world, after Saudi Arabia. To extract one barrel of synthetic crude oil from the san are required, nine barrels of water and 1.4t of sand. The equivalent of 600 Olympic sized swimming pools of new tailings are added everyday, says Soane Energy.

Charles Cherington, of Intervale Capital who is leading the new round of investment in Soane Energy, says, ‘there are people like us who acknowledge that’s there’s going to be oil for a while, and if you can reduce the general environmental damage, that's a good thing’.