Ultra-violet water treatment chemical free, favored for Lake Auburn

Officials from the Auburn and Lewiston water departments plan to build a new disinfection treatment plant using ultraviolet lamps to kill microorganisms. They've scheduled a ceremonial groundbreaking Tuesday, but work on the site — due online in 2011 — is already under way.

Officials from the Auburn and Lewiston water departments plan to build a new disinfection treatment plant using ultraviolet lamps to kill microorganisms. They've scheduled a ceremonial groundbreaking Tuesday, but work on the site — due online in 2011 — is already under way.

AUBURN  — A new $7.7 million water treatment facility being built on the banks of Lake Auburn won't do anything nature doesn't do already.

"It's just ultraviolet light, but a lot more of it," said John Storer of the Auburn Water District. "It's just light. It's not another chemical we're putting into the water, and that appeals to us."

Officials from both cities and the federal government — including Maine's U.S. Sen. Susan Collins — will be on hand for a ceremonial groundbreaking at 10:30 a.m. Tuesday at the construction site along Lake Auburn.

The facility is being built with federal American Recovery and Reinvestment Act money — a grant covering 30 percent of the costs and interest free loans for the rest.

Construction should wrap in 2010, and the facility should start treating Twin Cities' water in 2011.

Federal standards adopted in 2007 require municipal water supplies to have two disinfectant methods, whether or not the water is filtered. Those standards came about after an outbreak of cryptosporidium in Wisconsin in 2003. That's a type of protozoac parasite that can cause diarrhea.

"All surface water treatment plants have to meet those requirements, whether they've found cryptosporidium or not," said Kevin Gagne, deputy director of the Lewiston Water Department. Water drawn from Lake Auburn is tested for cryptosporidium regularly, but the parasite hasn't been found.

"Nonetheless, we have to prepare for it," Storer said.

The parasite is particularly susceptible to heavy concentrations of UV light.

"When we realized we had to meet that federal standard, we looked at several alternatives," Storer said. "Most involved pumping more chemicals into the water or were very expensive. But this was less expensive, and it does the job."

Currently, Lake Auburn water flows into an intake pipe along the eastern shore. It's treated with chlorine, and some of it is pumped to the Auburn Water District's Court Street station, treated with ammonia and piped to the district's customers. The rest flows to the Lewiston Main Street water station, where it's pumped out to Lewiston's customers.

The new facility will collect all of the water from the lake, running it through pipes ringed with high-intensity UV lamps first, before pumping in chlorine and delivering it to the two pump stations.

"They equate it to a lightning strike of UV light," Storer said. "That's what we're trying to achieve — a sudden blast of UV radiation that kills the parasites."

Later phases could bring the chlorine and ammonia treatment facilities to the same site.

staylor@sunjournal.com