How desalination will ease California's drought woes
The Golden State looks to the sea for a stable source of clean water.
As California's historic drought enters its fourth year, officials are searching for solutions to help ease the transition to what Gov. Jerry Brown described earlier this month as "the new normal." Mandatory water restrictions are immediate first steps, as are shifts to more drought-tolerant crops and native plants. But the buzzword increasingly on the minds of residents is desalination, a process already paying dividends for regions facing similar challenges around the world. Could squeezing clean water out of the sea offer the long-term solution officials are seeking?
The answer will be given later this year when San Diego receives the first clean drinking water from its new $1 billion Carlsbad Desalination Project. Built by Israel's IDE Technologies, the plant will be the largest desalination project in the Western Hemisphere, producing an average of 54 million gallons of fresh water per day. In an interview with San Diego 6, Mark Lambert, CEO of IDE Americas, said the Carlsbad project will eventually supply 7 to 10 percent of the city's drinking water.
"It's a start point," Lambert said. "The importance is that it provides us with water security. This is a way for us to get off of imported water and to make sure that in future drought years we have a basis for recovery."
The Carlsbad project is only the latest in a long line of hundreds of desalination plants that IDE has built over the last several decades around the world. Earlier this year, the company's Sorek plant in Israel, the world's largest desalination facility, began operating at full capacity. On average, Sorek produces 7 million gallons of fresh, potable water every hour – supplying 20 percent of the municipal water demand in Israel.
Both the Carlsbad and the Sorek plant employ a modern desalination process called reverse osmosis. It involves forcing seawater through a series of filtration membranes that remove the salt and other impurities. The energy necessary to achieve this filtration is immense, and one reason municipalities have skipped over the technology in the past. Recent engineering advancements over the last couple decades, however, have cut those energy costs dramatically. At the Sorek plant, a week's worth of water for one person costs less than 58 cents.
"The total seawater capacity planned for us next year [or sooner] will be 158.5 billion gallons," Dr. Raphael Semiat, a chemical engineer and desalination expert at the Israel Institute of Technology, told From The Grapevine. "This will cover 80 percent of the urban consumption in Israel or about 42 percent of the total drinking water consumption in Israel."
Based on energy use by Israel for 2013, Semiat revealed that desalination accounted for less than 1.4 percent of total consumption. He added that since most desalinated water is produced at night, at low tariffs, plants in Israel are "close to zero or even negative water consumption."
Success along the Mediterranean, however, does not mean California can expect carbon copy results. For one, the average daily consumption per capita in Israel is just over 26 gallons per day – whereas the average per capita in California varies widely from 500 gallons to 46 gallons per day. And let's not forget the giant elephant in the room: California's $46 billion agriculture industry, which consumes some 80 percent of all water resources. Factor in energy costs to pump water to farms throughout the state, and the prices associated with desalination begin to climb.
"We properly treat about 95 percent of our wastewater and use 80 percent of that for irrigation," Semiat says of Israel's agriculture industry, with farmers paying 25 cents for tertiary urban wastewater and 70 cents for desalinated water. He adds that with proper irrigation techniques, such as drip irrigation, farmers can further reduce costs and boost efficiency.
Despite the challenges that California faces, Dr. Semiat believes that with conservation measures, treated waste water, and new irrigation methods, there's a real place for desalination in the state's "new normal."
"There are better ways to use water," he said, "so desalination may be good part of the solution."
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