Even as San Diego County expects to add about 1 million new residents over the next 20 years, the question remains how the region will find enough water for a growing population.

But several local companies already have an environmentally friendly source in mind - the Pacific Ocean.

Vista-based I.W. Technologies is one such company. The firm has helped build a demonstration project that's already turning sea water to fresh water in Carlsbad, said Manoj Jhawar, president of the firm.

The $1 million demonstration project, funded by Stamford, Conn.-based Poseidon Resources Corp., can make about 35,000 gallons of water a day. It's the pilot for a much larger plant, capable of providing San Diego County with 50 million gallons of water a day.

That plant could be built for $230 million and would make enough fresh water to meet the annual needs of about 400,000 people, or 8 to 10 percent of current demand. In years to come, the plant could then be doubled in capacity, said Walter Winrow, executive vice president for Poseidon.

Poseidon is funding the entire cost of the plant privately. The San Diego County Water Authority would spend an extra $42 million for the pipeline and pumping stations to convey that water to San Diego's system, he said.

Winrow said it's Poseidon's model - handling the financing, permitting, and construction privately, in return for private ownership of the project for a number of years. The County Water Authority would have the option of buying the plant after five years of operation, he said.

Desalinating sea water makes a lot of sense, Winrow said. For one thing, the ocean is simply "the world's largest reservoir."

Also, the cost - which once was about $1,500 per acre-foot - has come down to the point where it can compete with more conventional water sources. Although the price of $909 per acre-foot for desalination still seems high, it's comparable to other sources once other factors are considered. For example, the desalination could be reduced by federal, state, and other subsidies, he said.

An acre-foot is about 326,000 gallons, or the amount of water needed by two families of four for a year.

Desalination also means jobs for San Diego. Construction of the plant could bring $150 million to $170 million for local companies and 2,100 jobs during construction. Once in operation, the plant will bring in about $37 million a year in contracts and 400 local jobs, Winrow said.

Jhawar said his company built two of the machines used in the demonstration project - the microfiltration and reverse osmosis equipment. He hopes his company will have a hand in the full-scale version, which could start construction in early 2005.

Pilot Project Uses Proven Technology

Over the next year, I.W. Technologies and Poseidon will collect data at the pilot project, which will help prove that a full-scale version is feasible. But he has little doubt, since many countries currently use desalination.

"Reverse osmosis is a proven technology. There's a plant in Florida where they're doing basically the same thing. And the entire Middle East is running on desalinated water. We're more or less re-proving operational facts that have been gleaned elsewhere."

Jhawar declined to state how much the pilot project cost to build, or how much it would cost to install this technology in the full-scale version, citing proprietary information.

Oceanside-based Hydranautics Corp. is also a part of the pilot project. They make the reverse osmosis membranes used in the machines built by I.W. Technologies, said Mark Wilf, vice president of corporate technology for Hydranautics.

Hydranautics is also looking to install its membranes in the full-scale plant once it gets built. This is an ongoing process, since the average lifespan of a reverse osmosis membrane is five to 10 years, he said.

The process could be lucrative, Wilf added. Every year, about 10 percent of the total 600,000 square feet of reverse osmosis membranes will be changed out. That could be worth about $1 million a year, he said.

Wilf said the technology is already proven - in the Middle East and elsewhere. Currently, Hydranautics ships about two-thirds of its product overseas, he said.

Reverse Osmosis Popular Elsewhere

Meanwhile, Steve Kappos, director of reverse osmosis sales for San Diego-based Koch Membrane Systems, hopes to get in on the action.

Like Hydranautics, Koch also makes membranes for reverse osmosis. Although the company does not yet have any business with Poseidon, it may become a supplier of the filters once the main project gets under way, he said.

Koch makes about $25 million a year on its reverse osmosis filters. Kappos finds it ironic that despite the local presence of two major reverse osmosis firms, the technology has not yet been tried locally for seawater desalination.

However, reverse osmosis has found other uses in San Diego County. For example, the Sweetwater Authority uses reverse osmosis to purify brackish water at a wellhead in National City, he said.

Now, Kappos is cheered at the prospect of using reverse osmosis for desalination in San Diego County.

"It's exciting to see us tap into the sea, like other countries, from Israel to Saudi Arabia - all these places from around the world. And we never have, but we have as much need for water as they do."

The project has tentative support from several local environmentalists. Carolyn Chase, who publishes the San Diego Earth Times, said the Sierra Club is reviewing the concept of desalination, and so far has determined that it has "great potential."

Weighing The Pros And Cons

Chase said that the desalination plant will be built next to an existing power plant, and will use the power plant's system of intakes from and discharge to the ocean. That means there will be less of an environmental impact than if the facility were built on a new site, she said.

Bob Richards, a spokesman for the Agua Hedionda Lagoon Foundation, said the desalination plant is a compatible use for the immediate area. The plant requires clean sea water to operate, so plant operators have a vested interest in preventing pollution, he said.

Meanwhile, water returning to the ocean has a slightly higher salt content, but this will have little effect on the ocean. The plant's discharge is diluted with other water before it reaches the outfall, Richards said.

Jim Elliott, administrative services director for the city of Carlsbad, said the desalination plant would mean 50 million gallons of water a day for the San Diego County Water Authority, with the new source of water going primarily to Carlsbad and other nearby cities, such as Oceanside. This is good news for the city, but he does have some concerns.

The addition of a desalination plant on the site of the power plant would be an "intensification of industrial use" on the coastal property, further blocking public access to Agua Hedionda Lagoon, he said.

The power plant is also one of the least efficient in the entire state. Building a desalination facility on the site makes it more difficult for the city to press the power generators to tear down the plant and build a more efficient one farther inland, Elliott said.

However, there are several benefits from building the desalination facility. It would provide reliable, high-quality water to the city, crucial to agricultural operations such as the Flower Fields, along with several high-tech businesses in Carlsbad, he said.

Cost Comparison

Any new sources of water:

About $650 per acre-foot.
Does not include costs of building additional pipelines and pumping stations to bring water here - which could cost millions of dollars.
Does not include cost of water treatment once water gets here.

Desalination:

$909 per acre-foot.
Includes amortizing construction costs and building the pipelines to connect the plant with the county system. Water passing through desalination plant is already treated.
Potential exists for a $250 per acre-foot subsidy from the Metropolitan Water District of Southern California, plus additional state and federal funds which could lower the price per acre-foot to the point where it is competitive with traditional sources.

Water Plant Would Share Space With Carlsbad Energy Plant

The desalination plant would take up about 3.2 acres. It would be built on the 100-acre grounds of an existing electric generating station in Carlsbad, the Encina facility owned by Cabrillo Power, said Peter MacLaggan, vice president of Poseidon Resources.

This allows the desalination facility to use an already existing intake for seawater, currently used as coolant at the power plant. The neighboring power plant would also supply the desalination facility with the juice it needs - a constant flow of 35 megawatts, or enough energy for 35,000 homes, MacLaggan said.

Since it takes two gallons of seawater to make one gallon of fresh water, 100 million gallons of seawater would be pumped into the plant every day. Of this amount, 50 million gallons would become drinking water, while the remainder would be discharged back into the ocean, using the Encina plant's outfall, he said.

The water leaving the desalination facility would be twice as salty as regular seawater, but it would be mixed with millions of gallons of cooling water from Encina. Thus, the resulting flow, once discharged into the ocean, would increase salinity by no more than 1 percent, at a point 1,000 feet from shore, MacLaggan said.

Bob Yamada, a project manager with the County Water Authority, said earlier studies have shown that it would be technically and economically feasible to build such a project. Since it would be built on an industrial site, it's a compatible land use, while the nearby water intakes and power generation reduce infrastructure costs, he said.