Healdsburg man uses heat to make clean water

Healdsburg’s Aaron Mandell wants to build a $30 million desalination plant in the San Joaquin Valley that would use the warmth of the sun to distill former irrigation water and reuse it on thirsty farms.

Mandell, an engineer and former Boston resident who has helped start a half-dozen companies, is the second Sonoma County entrepreneur with a business that takes an unorthodox approach to desalination - and who sees opportunity in a historic drought for boosting fresh water supplies.

“I don’t think the problem is going away anytime soon,” said Mandell, chairman and co-founder of WaterFX, a startup that now operates a trial plant in remote farmland along Highway 5 about 60 miles west of Fresno.

The solar distillation plant’s most striking feature may be its SkyTrough, a curved, reflective channel longer than a football field that can heat a pipe filled with mineral oil to roughly 660 degrees Fahrenheit. That is far hotter than needed to distill water that has been tainted not only with salt but also with such chemicals as boron and selenium.

With water shortages seemingly a way of life, California should imitate Israel in using desalination so successfully that it could become a water exporter, Mandell said. But the state’s businesses and municipalities need to do so in a way that doesn’t increase greenhouse gases and exacerbate climate change.

“The way to do that is to use a clean energy source that’s truly sustainable,” he said. For Mandell, sunshine fits the bill.

Four years of drought are prompting Central Valley farmers to look for new ways to meet their water needs.

“I think everybody is trying to stretch the supplies every way they can,” said Jennifer Bowles, executive director of the nonprofit Water Education Foundation in Sacramento. She recently spoke to a farmer who not only installed drip irrigation but also put up photovoltaic solar panels in order to provide the electricity needed to operate the new water system.

The challenge of finding adequate supplies of water is hardly confined to the Golden State.

Global water consumption is expected to increase 55 percent between 2000 and 2050, according to Securing Water For Food, an international coalition that includes the U.S. Agency for International Development and U.S. Bureau of Reclamation. As well, the United Nations estimates that by 2025, 1.8 billion people will live in areas with water scarcity, and two-thirds of the world’s population will face “water stressed conditions.”

To boost supplies, about 16,000 desalination plants have been built around the world. The prevailing technology involves reverse osmosis, which uses intense pressure and filtration to separate salt from water. But other methods are under trial, and their boosters insist that they can provide clean water while greatly reducing energy costs.

Desalination is often pictured as a process of drawing drinking water from the world’s oceans, the purpose of a $1 billion plant under construction on the coast at Carlsbad in San Diego County. But some entrepreneurs and experts see a greater opportunity in purifying brackish groundwater.

“It’s going to be much, much bigger than seawater desalination,” predicted John Webley, CEO of the Petaluma-based desalination company, Trevi Systems.

Webley, a former telecom company founder and the owner of Santa Rosa’s landmark McDonald Mansion, said brackish water requires far less energy to make potable than seawater.

His 5-year-old company has about 30 employees and is testing its “forward osmosis” desalination technology in the United Arab Emirates, Kuwait, Southern California and near San Francisco Bay.

Mandell, who moved with his family to Healdsburg two years ago, also spends his days as CEO of Seattle-based AltaRock Energy. That company in 2009 briefly conducted experimental drilling at The Geysers geothermal fields in northern Sonoma County.

Mandell formerly helped found Oasys, a company that has worked in forward osmosis desalination. And this spring Quidnet Energy, an energy storage startup in which Mandell is a co-founder and investor, announced it has received seed funding from various philanthropists, including the foundation of actor Will Smith and actress Jada Pinkett Smith.

A common thread among these companies is the nexus between water and energy and how it typically takes one to process or produce the other, Mandell said.

Founded three years ago, WaterFX has four employees and plans to open a main office in San Francisco, he said.

The company’s trial distillation plant, built with a $1 million state grant, lies near the Fresno County town of Firebaugh on land of the Panoche Water and Drainage District. The WaterFX plant is able to take former irrigation water and remove salts and other chemicals at the rate of 10 gallons per minute, or 14,000 gallons a day.