Water treatment system aims to reduce carbon footprint of fracking

A research team at the University of British Columbia is pioneering a water treatment technology for gas extraction that could significantly reduce the environmental impact of hydraulic fracturing.

Advanced dialysis cells developed at UBC use excess carbon dioxide to desalinate waste water for reuse and also produce hydrochloric acid and carbonate salts as byproducts on site, which are used in fracking and would otherwise have to be purchased and transported long distances, said Alfred Lam, who was a project member during his doctoral studies.

Hydraulic fracturing — popularly known as fracking — involves injecting large amounts of water, grit and chemicals into gas and oil wells under high pressure to fracture the rock and release natural gas. When the pressure is released, million of litres of contaminated, briny water backflows out of the well and must be treated, said Lam, who is helping shepherd the project as an adviser for Vancouver-based Chrysalix Energy Venture Capital, which specializes in early-stage clean energy projects.

Waste carbon dioxide is produced by gas flaring and the operation of generators at well sites.

The process is designed to address both carbon management and water desalination, while supplying a part of the industry's chemical requirements.

"A lot of technologies look at these issues as two separate problems, but we are simultaneously addressing both of them," David Wilkinson, a professor of chemical and biological engineering and a member of the Clean Energy Research Centre, said in a statement.

"What is most striking about this technology is that it uses waste inputs to do the work of desalination and it produces high-value chemicals at the back end," said Lam. "There are also situations at the front end, where the water available for fracking needs to be desalinated before being used."

If the technology were applied across Alberta in tight oil and shale gas extraction at commercialization, it could reduce carbon dioxide emissions by more than one million tonnes per year and reduce fresh water use by more than two billion litres, he said.

The system is estimated to mitigate about five kilograms of carbon dioxide per barrel of waste water treated and produce about two kilograms of carbonate salt and about 0.8 kilograms of hydrochloric acid per kilogram of carbon dioxide used in the reaction.

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Taxonomy

• Industrial Water Treatment
• Energy Efficiency
• Fracking