The two regular streams--one now having a surplus of positive ions and the other having a surplus of negative ions--are also connected to the third saltwater stream, which is the target for final purification. The two out-of-balance streams want to become balanced again, so they essentially strip the third stream of all positive and negative ions. The end result is de-ionized water that only requires some basic chlorination or ultraviolet treatment before being piped into homes and businesses.

Sparrow, who is also chief executive of Saltworks, says the process uses low-pressure pumps to circulate the water, meaning lightweight plastic pipes can be used instead of corrosion-resistant steel. Saltworks cofounder and president Joshua Zoshi says scaling up the system should be simple because the plastics and ion-selective chemicals used are plentiful and cheap. "Our next step is to engage with industry and work with potential customers to get the technology out into the field," Zoshi says.

Much of the research and pilot-plant funding to date has come from Canada's National Research Council, B.C. Hydro's Powertech Labs, and Sustainable Development Technology Canada, a federal agency that supports clean technology development through grants.

Rick Whittaker, chief technology officer at SDTC, says the company has a reasonable chance of success because the science behind it is sound and the approach is based largely on the creative integration of existing technologies. "There's technical risk," says Whittaker. "But we're quite confident they can scale it up."