News Feature | December 30, 2015

Nation's Largest Desal Plant Opens

Sara Jerome

By Sara Jerome,

The largest desalination plant in the U.S. opened in San Diego this month.

With the ceremonial opening “of the Western Hemisphere's largest ocean desalination plant, a new era began for water use in San Diego County — and possibly for the entire parched state,” the Los Angeles Times reported.

It’s “the first large-scale desalination plant in the state and only the second in the nation,” KPCC reported.

Backers are framing the plant as a long-term way to secure the supply as the state enters its fifth year of drought.

Local water managers said “it's meant to be part of San Diego County's drive toward greater control over its own water supply, which had its genesis in a drought that occurred more than 25 years ago. The region imported more than 90 percent of its potable water at the time, and the figure hasn't gone down much since then,” the Times reported.

The entire desalination process takes about 20 minutes, according to the plant’s website. NBC San Diego described the treatment method:

First, the saltwater is pretreated to remove algae and other organic materials. Then the water moves through microfiltration to remove microscopic impurities. To remove the salt from the seawater, the plant will strain the water through a reverse osmosis process. Under intense pressure the water is moved through semi-permeable membranes. Finally, some minerals are returned to the water that’s treated with chlorine.

Some ratepayers are wary of the cost of the project. “San Diego water customers may not necessarily be celebrating because they will have to pay an average of $5 more a month than they do now for water,” KPCC reported.

For more on the future of desalination, visit Water Online’s Desalination Solutions Center.