Desalination: Too costly to turn saltwater fresh during drought?


It's such a simple concept: You take an abundant resource like water from the ocean and you turn it into a desirable commodity, like water from the faucet. That's exactly what they are doing at a desalination plant on Santa Catalina Island.

In 1991, the Southern California Edison operation there became the first facility in California to get fresh water from the ocean.

"We take seawater, ocean water, and we convert that to drinking water for the island," said SCE Manager Ron Hite.

Hite says the facility provides the island with up to 200,000 gallons of drinking water per day. In the off-season, that's almost 90 percent of the island's needs.

"The primary resource is coming out of the interior of the island, but there are times when we need to supplement that with this plant," said Hite.

The way it works is pretty straightforward: The water is pumped into four separate units where electrical motors pressurize the water, forcing it through reverse-osmosis membranes.

"That's where the salt is extracted," said Hite. "And then from there we add chlorine to disinfect the water, and send it to the distribution system. It's really that simple."

So if a relatively small plant does such a good job of providing Catalina with so much water, then why aren't there desalination plants up and down the California coastline? The answer is money.

"This water, as we talked about, is roughly four to five times more expensive just based on the simple fact that you have to pressurize that water electrically, so the more economical solution is the well water," said Hite.

Critics say the plants kill fish that get sucked into pumps. And there are concerns about the highly concentrated saltwater that's pumped back into the ocean.

"When we send that back to the ocean, that's very tightly monitored and controlled, because that water has more salinity in it than what we pulled out, and so we have strict regulations on that," said Hite.

Still, several California communities are considering desalination plants as a way to supplement their current water supplies. In Carlsbad, a billion-dollar desalination plant should be online by 2016.

And over time, desalination could prove to be a cost-effective solution, depending on how long California's current drought lingers.

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