Desalination comes to Southwest County

By: DAVE DOWNEY - Staff Writer | Saturday, August 13, 2005 7:42 PM PDT ∞

SUN CITY ---- As efforts to turn sea water into drinking water struggle to get off the ground along the coast, the practice of removing salt from ground water is flourishing some 50 miles from the ocean.

Eastern Municipal Water District, an agency that distributes water to several Southwest County communities, recently built two desalting plants in Sun City. One is up and running and the other will be in operation by the end of this month, said Mike Garner, assistant general manager of resource development. The $60 million project is aimed at purifying water pumped out of 10 wells in the Sun City-Menifee-Perris area.

The agency is not stopping there, either. It has plans to build a third plant in Romoland.

"We're hoping to have it online within the next five years," Garner said.

Ultimately, the three plants collectively will produce a total of 12,000 acre-feet of drinking-quality water annually, he said. That's enough to supply 24,000 homes, or 80,000 people, and it represents 12 percent of the agency's total deliveries.

Eastern serves a wide swath of the Interstate 215 corridor, including Menifee, Sun City, French Valley and parts of Murrieta.

The district's experience with desalination holds promise for the future, officials say.

"I think it's going to become an important part of Southern California's water supply," Garner said. "We like to think that we are kind of a model."

Possible, not practical

Extracting salt from water is something that has long been possible, but rarely practical in the United States, Garner said. The cost has been so high ---- particularly when stacked up against the cost of say, piping water in from distant rivers and lakes ---- as to discourage most agencies from even considering it.

Southern California Edison built a desalination plant on Santa Catalina Island, then shut it down in the early 1990s because it was costing about $3,000 to produce 1 acre-foot. Recent advances in membrane technology, however, have greatly reduced the cost and have brightened desalination's long-term outlook, experts say.

"The technology has been around for a long time," Garner said. "We've reached a point in terms of the availability of water where desalination is being seen as a much more attractive alternative for water supply than it has been in the past."

Garner said his district is producing desalted water for about $700 an acre-foot. That's still a lot more than the $450-per-acre-foot tab for bringing in imported water from Northern California or the Colorado River. But the gap has narrowed significantly in recent years, and a regional program provides a way for Eastern to make up the difference, he said.

Metropolitan Water District, the giant Los Angeles-based wholesaler that supplies half of urban Southern California's water, is offering up to $250 per acre-foot to member agencies, of which Eastern is one, to encourage desalination projects, said Bob Muir, district spokesman.

Besides the allure of the subsidy, Garner said, desalination is attractive because it is provides a way to shore up other sources.

For example, about one-quarter of Eastern's water is recycled waste water. While spraying reclaimed water on golf courses and parks stretches other supplies, that practice presents a problem. After it is used on area turf, the recycled water soaks through the soil and, because it is high in salt content, worsens the quality of already salty ground water in areas such as Menifee, Sun City and Perris.

Through the desalting process, the district is able to clean up and use an otherwise unusable supply of salty ground water. At the same time, he said, the process allows Eastern to continue its heavy reliance on recycled water by erasing the fear of contaminating ground water.

"What our system does is bridge the gap between fresh water supply and recycled water use," Garner said.

Eastern decided to try desalination because its ground water is loaded with a salt concentrations of between 2,000 and 3,000 parts per million. Placing that into perspective, Eastern spokesman Peter Odencrans said, water is generally considered too salty for use on the farm if the concentration exceeds 1,000 parts per million and too salty for use in the home if levels reach 500 parts per million.

The process removes 8 tons of salt for every 1 million gallons of water, Odencrans said.

"Desalination, for EMWD, is a result of our desire for long-term salinity management in our ground water basins," Garner said.

Not as salty as the ocean

The byproduct of the purification process ---- a salty brew dubbed brine by officials in the water industry ---- is piped 62 miles down to the ocean near Fountain Valley in Orange County. District officials maintain that dumping the waste into the sea is not harmful to the environment because the ocean's salt concentration is greater than that of the waste water, which is three times as salty as the ground water.

The concentration in the local ground water being scrubbed is one-tenth the amount in ocean water, which runs around 30,000 parts per million, Garner said. That makes ground-water desalting substantially cheaper than sea-water desalination, because it takes less power to squeeze the brackish water through filtering membranes, he said.

Muir said the cost of desalted sea water is running around $1,000 per acre-feet these days, and in some cases lower. Peter MacLaggan, senior vice president of Poseidon Inc., the Connecticut company preparing to build a sea-water desalination plant in Carlsbad, expects to begin producing drinking-quality water at a cost of $861 in 2008.

Anatole Falagan, assistant group manager for water resource management at Metropolitan Water District, said his district's board last month gave the green light to write contracts for subsidizing part of the cost of five seawater desalination plants around Southern California, including the proposed San Diego County Water Authority plant in Carlsbad. The other sites are in Orange County, Long Beach and Los Angeles, where there are two.

"We're finalizing them (the contracts) for signature as we speak," Muir said. By 2015, he said, Metropolitan expects those five plants will be producing, collectively, 142,000 acre-feet.

As for ground-water desalination, that is more widespread, Falagan said. A program for helping defray costs of those projects has been in place 13 years.

Muir said Metropolitan since has funded 20 such projects, including Eastern's system, at a total cost of $50 million. Eighteen of those systems are currently operating and producing a combined 64,000 acre-feet a year.

Eastern's Odencrans suggested it is a healthy sign for the future that Southern California leaders are addressing head on the salt buildup in regional water supplies.

"Civilizations in the past have gone out because of salt problems," he said.

Contact staff writer Dave Downey at (951) 676-4315, Ext. 2616, or ddowney@californian.com.