Carlsbad commissioners review desal plant data

By: BARBARA HENRY - Staff Writer | Wednesday, December 21, 2005 10:52 PM PST ∞

CARLSBAD ---- What will drinking water that's produced from the ocean taste like? Will this new water hurt plants or the city's water pipes? And, will the extra-salty byproduct harm the sea?

These were among the questions that the Carlsbad Planning Commission had Wednesday night as it reviewed data on a proposed $270 million desalination plant. Planned for land within the Encina Power Station along Carlsbad's waterfront, the plant is expected to produce upward of 50 million gallons a day of drinking water.

Wednesday's session was only informational. The proposal will go back to the commission in February for a full hearing and a vote. Who is going to buy the water and even who is going to build the plant are still in debate, but commissioners didn't focus on those issues during the initial portion of their question-and-answer workshop.

Commissioner Marty Montgomery stressed that he wanted to ask the sort of questions that the average Carlsbad resident would want answered. He had three key questions regarding the taste of the water, the effect its production would have on the Pacific Ocean, and the impact on Carlsbad if the plant isn't built. By press time, the city staff had covered the first two issues.

Bob Greaney, a city deputy public works director, said the water that now comes out of Carlsbad's taps is from the Colorado River. Its highly dissolved mineral content gives it a strong, distinctive taste, he said. It's also what causes the chalky deposits around household plumbing fixtures, he added, commenting that the desalinated water would have few mineral deposits.

"There would be a slight difference in taste ---- generally, the (desalinated) water would be a bit more bland," Greaney said.

Montgomery laughed, and said he thought people might not mind that.

There are other concerns, though, with the "bland" water. Unless extra mineral content is added during the production process, the new water may "aggressively" eat away at the city's pipe system, Greaney said.

Commissioners had other questions on water quality, including ones about how much boron ---- a chemical in seawater ---- would end up in the drinking water.

"We're confident that the boron levels will be at or below the health standards now," Greaney responded.

Researchers are now looking into whether the boron levels will cause any of what's referred to as "tip burn" damage to ornamental plants, he added.

The production of drinking water from saltwater leaves behind an extremely salty slurry. That byproduct would be dumped into the power plant's outflow pipe where it would mix with other water before being returned to the Pacific Ocean. Commissioners asked how the extra-salty water would affect the marine environment near the outflow pipe.

A consultant who produced an environmental impact report for the project said computer modeling scenarios only turned up one "worst-case scenario" in a 20-year period. Even at that worst level, the plant's byproduct wouldn't have a significant impact on the marine environment, he said.

Put forward by the Connecticut-based company Poseidon Resources Corp., the plant is only at the beginning stages in the review process. It will need numerous permits, including one from the California Coastal Commission.

The desalination plant proposal that Carlsbad is considering would be a privately built and operated facility that would sell its water to districts within the county. Poseidon Resources is also negotiating with the San Diego County Water Authority to build a publicly owned plant on the same site. The result of those talks may change the character of the plant that could be built in Carlsbad.

Contact staff writer Barbara Henry at (760) 901-4072 or bhenry@nctimes.com.

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