UV treatment plan gets state's blessing

By: TOM PFINGSTEN - Staff Writer | Monday, May 28, 2007 10:05 PM PDT ∞

FALLBROOK -- The Fallbrook Public Utility District will pursue plans to build an ultraviolet treatment center below Red Mountain Reservoir, officials said last week.

The system, which will cost between $3 to $5 million, has been given the first of several green lights needed from the California Health and Human Services Agency, said the utility district's chief engineer, Joe Jackson.

"We're going to be budgeting construction money a year from now, so we'd hope to start construction in the summer of 2008," Jackson said, adding that the district's consultant on the project, McGuire-Malcolm Pirnie of Santa Monica, has already started designing it.

"There are some details that we're going to meet with (state health officials) and discuss," which will happen in a meeting during the first week of June, he said. "We're going to take a preliminary design with us when we go."

The system is needed to fulfill a new Environmental Protection Agency rule that requires all open reservoirs to be fitted with covers or equipped with filtration plants by 2012, so that outgoing drinking water is treated one last time before being delivered to customers.

The water stored at Red Mountain has already been treated several times before it reaches the 440 million-gallon reservoir, which was built in the 1970's to provide an emergency source of drinking water for the greater Fallbrook area.

It's not practical to cover the huge Red Mountain Reservoir because it has a 22-acre surface area, and a standard filtration plant would cost too much, Jackson said.

The water flowing out of the reservoir has never violated water quality standards, and officials said they were frustrated at first with the new rule because it called for an expensive, full-blown facility that they said would be redundant in this case.

Using ultraviolet light to kill pathogens in the water is a much cheaper solution, but its one that required the state's blessing because it is a ground-breaking new technology, Jackson said.

A full-blown plant could cost as much as $20 to $30 million, he said, whereas the ultraviolet system will cost only $3 to $5 million.

"These (UV treatment systems) are pretty rare, they have to be approved on a case-by-case basis, and quite frankly, we're the first in California to take this approach with an open reservoir," he said.

The process is not necessarily better than old-fashioned filtration, but is simply cheaper and a bit faster, because in a filtration plant the water would have to be disinfected using a similar process after being filtered, anyway, Jackson said.

He said zapping the water with UV rays won't affect the mineral balance in the water, but could reduce some contaminants that harm the taste, although the difference probably won't be noticeable to the average customer.

Patti Roberts, a health services spokeswoman for the state, confirmed in March that Fallbrook would be the first water district in the state to use ultraviolet technology in this way.

"California does not have a UV system that treats water from uncovered finished water reservoirs, which are potentially exposed to contamination from birds, animals and the environment in general," Roberts wrote in an e-mail in response to questions from the North County Times.

"There are very few of these uncovered finished water reservoirs in California -- most have already been covered," she wrote.

On May 11, the state notified the utility district in a letter that its concept was acceptable under the EPA rule, but placed some conditions on the project.

One condition is that the district cannot relax the other measures it has in place now to ensure the water flowing out of Red Mountain Reservoir is clean.

The other conditions are highly technical and address everything from how effectively the system will kill pathogens to monitoring how algae effects the ultraviolet treatment process.

The letter that the state sent to the district says that officials will need to evaluate the final design before the project can be built and put into service.

Jackson said the district will have a better idea of its timeline after the meeting with state officials in early June.

-- Contact staff writer Tom Pfingsten at (760) 731-5799 or tpfingsten@nctimes.com.

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