Completion of Yuba City’s most expensive capital improvement project could easily go unnoticed.

The project won’t let people take a stroll on a downtown street, or a splash in a park - as do two of the city’s more high-profile projects involving Plumas Street and Gauche Park.

But when residents using city surface water turn on their faucets, the recent $24 million investment in the city’s water treatment plant will provide more safety and reliability, said Utilities Director Bill Lewis.

On Monday, the state Department of Public Health gave Yuba City permission to start operating its new membrane filtration plant. It uses 1,400 membrane filters to purify the city’s drinking water. The city has been using the more traditional sand and anthracite materials.

The project also installed two pumps and a large-diameter pipeline, added a water storage tank, and reworked the sedimentation tanks.

The plant is 95 percent completed and will give the growing city some additional water treatment capacity, increasing the current 30 million gallons per day to 42 million.

Last summer’s 26 million gallon per-day usage was close to maxing out the plant, which has a lower working capacity than the 30 million gallon per-day rating.

“We can’t run flat out at capacity,” said Lewis.

While the water coming out of faucets probably won’t taste different, it may be better protected against harmful bacteria.

“The biggest advantage is the security of filtration,” said Lewis. “It’s just a safer way to remove the bacteria.”

It will also conserve the city’s share of Feather River water by using less water during backflushing.

Costs of the plant project are paid with impact fees that the city charges for water hookups.

“This is the biggest capital project the city’s ever done as far as dollars,” said Lewis.

In this case, new technology is cheaper than old - a conventional plant expansion would have been more costly, requiring more concrete, said Ian Pietz, associate engineer with the city’s Utilities Department.

The City Council awarded a $21.6 million contract in August 2005 to C.W. Roen Construction Co. of Danville to increase the plant capacity. Design costs of $1.5 million, plus a change order, increased total costs to $24 million.

Appeal-Democrat reporter John Dickey can be reached at 749-4711. You may e-mail him at jdickey@appealdemocrat.com.