Article courtesy of Bok Knudsen | April 29, 2015 | The Examiner | Shared as educational material
An MIT team of scientists and a water technology company, Jain Irrigation Systems, have teamed up and discovered a remarkable new way to desalinate water. The Independent reported on April 28 that the new system would use solar power to charge batteries in order to remove salt from water. This is important because, as you are most likely aware, California is experiencing unprecedented drought conditions that have left the state on the verge of a catastrophic situation.
The batteries are charged by solar power and then they use electrodialysis to purify the water. Electrodialysis works by moving water between two electrodes, one of which has a positive charge and the other negative. Charged ions are removed from water moved through these electrodes. Since salt in the water is charged as well, it is attracted to the electrodes, thus drawing it out of the water. The water can then be further purified by use of ultraviolet rays and traditional methods. 90 percent of saltwater fed into the apparatus could be recovered as drinking water, an astonishingly efficient model.
What makes this method so much better than existing methods is that since it uses electrodialysis, the parts can last longer than in traditional osmosis type purification processing machines. This would make maintenance much easier and cheaper over time. Water desalination plants can carry a hefty price tag, easily hundreds of millions of dollars each and as much as a billion, so anything that can help ease the cost would be immensely helpful.
The MIT and Jain team won the 2015 Desal prize for their efforts. The prize, as its name suggests, is rewarded for working to use technology and other methods to bring drinkable water to people in areas that need it. It includes $160,000 reward and an investment in helping develop the technology better for real world uses.
Other technologies currently being tapped to help with the California water issues include upgrading traditional membranes in reverse osmosis systems, a new “forward osmosis” system, and reclaiming some wastewater for energy production and other usage.