In the News

DESALINATION PLANT COULD HELP SOOTHE SANTA CRUZ WATER WOES

By April Short & Michele Lanctot

City on a Hill Press, 04/10/2008

Imagine not having enough water to brush your teeth. That could be a reality if Santa Cruz ever faces a water shortage on par with the drought of 1976-1977.

The results, according to Bill Kocher, director of the Santa Cruz Water Department (SCWD), would be devastating. “We are talking businesses shutting down,” he said.

Santa Cruz is ill-prepared to handle a major drought, and saltwater contamination threatens the Soquel Creek Water District’s underground wells. The two departments have undertaken a collaborative effort to examine solutions to the water supply issues both cities face.

After years of research, an ideal source of additional water remains elusive. Options like dams, reservoirs, and diversions would not be adequate because they are highly intrusive and costly. Since the late 1990s, the SCWD has been working on an Integrated Resources Plan (IRP). The plan identified seawater desalination as the best option.

Desalination is the process of converting ocean water into safe drinking water. Located at UC Santa Cruz’s Long Marine Laboratory, the Seymour Center is hosting the pilot desalination plant, which tests optimal ways to build and operate a full-scale desalination facility. The site has been in the making for months and is scheduled to open to the public in the next two weeks.

The most common form of desalination is reverse osmosis, which uses high pressure to force saltwater through extremely thin membranes, separating the salts and minerals from the potable water.

The process requires excessive energy, but the plant uses devices that recycle the water and create less work for the pumps, explained Erik Desormeaux, a scientist involved in developing the pilot plant and testing the methods of reverse osmosis desalination.

“The energy-capturing devices can cut energy cost up to 60 percent at their full potential,” Desormeaux said.

The pilot plant compares conventional and innovative pretreatment methods. The process will combine the “slow sand method” — a biological process in which unpressurized water is passed through a sand filter — with reverse osmosis.

“This is an extremely green process,” Desormeaux said, “but requires more space than the others — a minor tradeoff.”

In another effort to minimize environmental impact, the pilot plant has tapped into the Seymour Center’s existing seawater intake system. The brine and freshwater are then reconstituted to be used for the tanks of the Seymour Center and returned to the ocean in their original condition.

Legislation was recently passed to expand and add new protections for the national marine sanctuaries of Northern California. Many coastal cities facing water shortage have to go through a rigorous process to obtain permits for desalination facilities. However, if Santa Cruz commits to lessening its environmental impact, permits can be obtained more easily.

“The task force involved is actually being incredibly mindful here,” said Shauna Potocky, manager of the Seymour Center. “The pilot plant fits in with our mission to educate people about the role scientific research plays in understanding and conserving the ocean.”

Because of Santa Cruz’s innovative methods of testing, the results may be useful to other communities facing similar water shortage issues.

The proposed full-scale plant will produce 2.5 million gallons a day. Soquel Creek will use this during the year to stockpile its groundwater, and if a drought hits, Santa Cruz will use the water from the plant and Soquel Creek will use its groundwater supply.

The plant’s $4 million bill is being reduced by two grants from the Department of Water Resources and the State Water Resources Control Board. The two districts will split the rest of the cost. If a full-scale desalination plant were to be put into place, it would cost approximately $35 million.

“Desalination of ocean water is not a plan to encourage growth by any means, but it is a good backup if growth happens,” Kocher said. “Our goal is really just to provide the needed backup water supply in case of a dangerous drought situation.”

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