Solar desalination

Solar Desalination Solves Many Problems

(3BL Media/Justmeans) - It seems fitting, with World Water Week just behind us, and with news of the latest, even more dire assessment of the impacts of climate change from the IPCC still making the rounds, that we should share this story which shows one very effective way to connect the dots.

Given the changes coming down the climate pipeline, water is going to be an area of particular  concern, because we are so completely dependent on it to live, and because it’s going to be getting harder to find. Droughts are expected to increase. Snow melt, which often provides water in many regions for most of the year, is accelerating, often providing floods instead of nourishment, and changing rainfall patterns can deprive areas of water that previously had plenty.

Water and energy are inextricably linked. It takes lots of energy to pump water from one place to another and today’s thermal power plants with their cooling towers are among the nation’s largest consumers of water.

For all of these reasons, the announcement of a new solar desalination initiative is welcome news.

WaterFX is using a 377 foot-long solar array to turn brackish water, a mixture of fresh and salt water, into pure distilled water, also producing concentrated mineral salts as a byproduct. Brackish water is commonly found in estuaries, deltas and mangrove swamps, but it is becoming increasingly common as agricultural drainage as freshwater aquifers are depleted. This phenomenon is known as saltwater encroachment. It can also be expected to increase as sea level rises.

The Water FX technology, which has been dubbed “drought buster,” is currently being demonstrated in a $1 million project at the Panoche Water and Drainage District in Firebaugh, which serves the agriculturally rich Central Valley in California. Their Aqua4™ Concentrated Solar Still uses an approach that differs significantly from conventional desalination technology. Not only is it powered by the sun instead of electricity or other means, but it also relies on evaporation rather than reverse osmosis (RO) which is more commonly used. RO has been considered the more cost-effective approach due to the high energy cost associated with evaporation, but with the Concentrated Solar Still, the energy is free and clean. The rate at which fresh water can be recovered from salt or brackish water is also higher, as much as 93%, compared to 50% for RO systems. It also produces commercially desirable concentrated mineral salts as a byproduct.

A larger, commercial version of this plant, will be built later this year on 31 acres of land, capable of producing roughly two million gallons per day.

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