News Feature | February 21, 2014

Electrodialysis: The Future Of Desalination?

By Sara Jerome

oceanreg

Is electrodialysis the next great desalination technology?

Possibly, according to the MIT Technology Review. Electrodialysis "works by allowing sodium and chlorine ions to pass through a membrane in the presence of an electric field, leaving purified water on the other side," the report said. 

But for this method to become viable, certain hurdles must be cleared. "Electrodialysis has the potential to desalinate seawater quickly and cheaply but does not remove other contaminants such as dirt and bacteria," the report said. 

Now, in a potential breakthrough, researchers at the institute believe they have pinpointed "a way to produce clean drinking water in a single step using electrodialysis," the report said. 

Daosheng Deng and other researchers at MIT are examining this possibility. His team claims that "the key is to place a layer of porous material close to the cathode which then acts as a filter and removes anything that cannot pass through the micropores," according to the report. 

The researchers said in the article: “We were able to kill or remove approximately 99 percent of viable E Coli bacteria present in the feed water upon flowing through the shock electrodialysis device with applied voltage.” 

The backdrop: The most common method of desalination is reverse osmosis (RO). "This works by pumping water through a membrane that does not allow sodium or chlorine ions to pass. That’s significantly less energy intensive than traditional desalination methods but is limited by the rate at which water can pass through the membrane," the report said. 

Even without perfect technology, how hot is the desalination market these days? It's getting hotter, according to CNBC, as a result of the California drought.  

"In light of the extreme drought in California, people are wondering how quickly desalination plants can come on line," said Christiana Peppard, an expert on fresh water ethics, in the report. "But desalination is not a panacea. It's only as good as the contexts in which it is deployed and the goals that are set for it."

Officials in California are watching Israel's track record with desalination for hints on how to move forward, according to Bloomberg Businessweek"In Israel, desalination now provides about one-quarter of the country’s water supply," the report said. 

For more, check out Water Online's Drinking Water Desalination Solution Center

Image credit: "ocean," © 2005  Stephen Edgar - Netweb, used under an Attribution-ShareAlike 2.0 Generic license: http://creativecommons.org/licenses/by-sa/2.0/deed.en

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