WaterFX Sees Solar Desalination of Ag. Runoff As One Way To Address The World's Water Problem

1/07/2014 FORBES. By Peter Kelly-Detwiler. Aaron Mandell, Founder and Chairman of WaterFX, looks at California’s water issue like a classic entrepreneur. Where others see problems, he sees opportunity for improvement and profit. And that opportunity is huge. It is common knowledge that access to clean water is a mounting problem across the globe. However, few places have water issues as complex and challenging as California, which has been dealing with the water issue for generations (some may remember the 1974 Jack Nicholson, Faye Dunaway film ‘Chinatown’ that focused on the California Water Wars of the early 1900s). In that state, the issue is highly complex, layered in a complicated history of rights, claimants, and the physical reality of too much demand for a limited supply. Water issues are also inextricably linked to energy issues: it takes an enormous amount of energy to pump, treat, and move water. So the water problem is not only limited to H2O, it’s a costly energy issue as well. Mandell hopes to change that reality. He has a vision for how to make that happen, starting with a clean and modular technology and an open source approach that he hopes will stimulate a growing community of solutions providers. His company, WaterFX has created a solar-powered desalination system to treat agricultural drainage that is not only benign from an energy standpoint, but also leaves the agricultural environment in better shape. WaterFX has successfully piloted a 6,500 square foot system with California’s Panoche Water District over the past six months, producing almost 500 gallons of clean water per hour. Panoche is one of the water districts in California taking a leading role in addressing the state’s water crisis. Following on the pilot’s success, the Water District has now agreed to work with Mandell’s company to expand the system to produce 2,200 acre-feet per year.

Here’s how the system works:
Instead of the traditional desalination approach normally used to treat seawater, which uses a high-pressure reverse osmosis system that forces salt and other solids through a membrane, WaterFX cleans water through use of a Concentrated Solar Still. It uses existing technology, adapting 400 kilowatt parabolic solar troughs originally designed for power generation. The solar troughs concentrate the sun’s energy and heat a pipe containing heat transfer fluid that transfers the heat to a heat pump, further increasing efficiency. This heat is then utilized in a distillation process to evaporate clean water out of source water (in this case, agricultural drainage water that contains salts, fertilizers, and other impurities). The condensate is then recovered as pure H2O. Since the sun doesn’t always shine, a thermal storage system is used to hold the excess heat so that the process can function around the clock. Mandell – who studied groundwater engineering in school and has been involved in previous water-related start-ups – migrated to energy work in recent years and became convinced that the energy-water nexus was an area worth devoting attention to.
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