Dalhousie University develops energy-efficient wastewater treatment

Dalhousie University researchers have developed a new wastewater treatment method they say is more energy-efficient.

The researchers developed the world’s first municipal-scale UV light-emitting diodes (LED) reactor for wastewater treatment, according to a news release from the university. The invention is currently in use in Eastern Passage, N.S.

Graham Gagnon, director for Dalhousie’s Centre for Water Resources Studies, said typical wastewater treatment uses UV mercury bulbs.

“The challenge with mercury is it’s toxic and it requires a great deal of maintenance,” he told CTV News Atlantic’s Todd Battis on Thursday. “(UV LEDs) emit light at a UV wavelength.”

The release says wastewater flows past thousands of tiny diodes in the UV LED reactor, allowing it to be bathed in targeted UV light without high temperatures.

“UV light has been well known to disinfect parasites and bacteria,” Gagnon said. “It was thought the mercury bulb was the only source of light.”

The release notes the new system could help reduce the amount of mercury bulbs in use around the world.

“In the next few years, we expect to see this UV LED technology used at full scale, and it could be transformative for Halifax Water and the entire industry,” says Dr. Wendy Krkosek, acting director of environment, health and safety with Halifax Water, in the release. “We are proud to be at the forefront of this research with Dr. Gagnon and Dalhousie and to know that our commitment to innovation will create greater operational efficiencies that will ultimately benefit our customers.”

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