Treated wastewater would be heat source;wouldn't touch pool

If officials are able to secure the funding, Crescent City residents could find themselves swimming in a pool heated by the city's treated wastewater.

City officials hope to use $935,000 in Proposition 50 money it received from the state to build a geothermal heat pump for the Fred Endert Community Swimming Pool and the Crescent City Cultural Center using treated water from the wastewater treatment plant. Although the heat from the wastewater would be used to heat the pool, the wastewater itself would remain in a pipe separate from the pool water, said Public Works Director Eric Wier.

"That wastewater that leaves the treatment plant will not leave that pipe," he said. "It'll just go through the pipe, it runs through coils that heat the water and then it will return to the wastewater treatment plant."

The Crescent City Council on Monday unanimously approved a $160,000 contract with Redding-based ArcSine Engineering to design the geothermal heat pump. The Council's approval is contingent upon the city obtaining an extension from the state to use its Prop 50 funds. The city currently has until March 31 to spend that money, Wier said, but is hoping for a year's extension.

It's expected to cost $700,000 to construct the pool heating system, Wier said. Heating the Cultural Center would add an estimated $200,000 to the cost. If the project is completed, the city could annually save $30,000-$40,000 at the pool and $5,000-$10,000 at the Cultural Center, Wier said.

Wier said the city had planned to use that funding to design and build an irrigation system at Beachfront Park that would use the city's treated wastewater. But the Regional Water Quality Control Board requires that the treated wastewater be tested on a consistent basis.

Also, the city could only irrigate the park at night when the flow into the wastewater treatment plant was low, Wier said. To do that, the city would have had to build a tank to store the wastewater until it could be used. This put the cost of the project at more than $1 million, Wier said, plus the cost of the ongoing testing.

"The grant money wouldn't pay for this project anymore," he told the Council.

That was when the city decided to pursue installing the geothermal heat pump to heat the pool and Cultural Center. The contraption would pump wastewater from the treatment plant through an 8-inch pipe to an electric heating unit, Wier said. The unit would reduce the temperature in the wastewater by about 10 degrees before it returned to the treatment plant.

Heat extracted from the treated wastewater would be transferred to a closed potable water system that is heated to about 130 degrees before going through a heat exchanger to heat the pool water. That same 130-degree water would then go into an air handling unit that would heat the locker rooms and lobby, according to the city's staff report.

In order also heat the Cultural Center, an additional mechanical building would need to be constructed between the pool and cultural center, the staff report said. ArcSine would evaluate the feasibility of increasing the size of the mechanical equipment to include heating the Cultural Center as part of its design contract.

The wastewater sent back to the treatment plant would ultimately be discharged into the ocean, Wier said.

"It would be a water that is more consistent with the discharge waters that it goes to," he said. "It turns into a win-win situation."

The pool is currently heated with propane.

"I think it's a great project," said Mayor Rich Enea. "Anything to keep pool costs down and to benefit our citizens."

Proposition 50 provides grant money for water quality improvements and was approved by voters in 2002. When it passed, Proposition 50 money was used for water improvement projects throughout the North Coast, Wier said.

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