New York, Nov 24 (IANS): Using only sunlight and nanoparticles, researchers in Canada have developed an effective, inexpensive and green process to remove contaminants from oil sands wastewater.

Frank Gu, professor at the University of Waterloo in Canada, found that photocatalysis -- a chemical reaction that involves the absorption of light by nanoparticles -- can completely eliminate naphthenic acids in oil sands wastewater within hours.

Naphthenic acids pose a threat to ecology and human health. Water in tailing ponds left to biodegrade naturally in the environment still contains these contaminants decades later.

"With about a billion tonnes of water stored in ponds in Alberta, removing naphthenic acids is one of the largest environmental challenges in Canada," said study lead author Tim Leshuk from University of Waterloo.

"Conventional treatments people have tried either have not worked or if they have worked they have been far too impractical or expensive to solve the size of the problem. Waterloo's technology is the first step of what looks like a very practical and green treatment method," Leshuk noted.

Unlike treating polluted water with chlorine or membrane filtering, the new technology is energy-efficient and relatively inexpensive, the researchers said.

Nanoparticles become extremely reactive when exposed to sunlight and break down the persistent pollutants in their individual atoms, completely removing them from the water.

This treatment depends on only sunlight for energy, and the nanoparticles can be recovered and reused indefinitely, said the study published in the journal Chemosphere.