How to Desalinise Water Using Half the Energy of Traditional Methods 

By Bryan Lufkin on at

In the next ten years, Earth’s population is expected to increase by one billion, and only 3% of our planet’s water is fit for drinking. Most of that relatively small amount is trapped in frozen glaciers. But Egyptian researchers have developed a way of removing the salt out of sea water for our growing population in a way that’s super energy efficient.

Desalination is an expensive process that also uses a ton of energy: more than 200 million kilowatt hours per day around the world. So a team at the University of Alexandria figured out a way to address their own country’s freshwater concerns with a new process that uses less than half the power of traditional desalination methods. Their new technique was published this week in a paper in the journal Water Science & Technology.

It relies on a familiar process called “pervaporation,” which involves pressurising ocean water through a salt-catching membrane, and then vaporising and condensing it so it’s drinkable. There’s nothing new about that—it’s decades old, Gizmag reports. But what the researchers did was develop a new polymer membrane made of cheap, local materials, that can be mass produced in printed and cut sheets for widespread use.

In tests with simulated seawater, the salt rejection rate was remarkable: over 99.7%. Those local ingredients, like cellulose acetate powder, bind to the salt particles as the water moves through the membrane. And since the process uses so little electricity, it’s sustainable, and drives the price down even further. A pilot program is currently being planned at a desalination plant.

New ideas of water treatment methods are always welcome: We recently reported on this Indian startup that came up with a clever way of using rainwater caught in re-designed wells, which works great for smaller villages or communities. To make our planet ready for more humans in the very near future, we need to be ready, and emerging technology like this new desalination process in Egypt is crucial.

[Water Science & Technology via Gizmag]

Top image: Salt water pool on the Salinas Grandes salt flats in Argentina’s Jujuy province. Credit: Shutterstock