Alternative desalination process cleans and sterilizes water

MIT Technology Review : Desalination is an important technology for providing drinkable water to large portions of Earth’s population. The traditional process via vacuum distillation is expensive and energy intensive; a common alternative, reverse osmosis, which pushes water through a membrane filter, is less intensive but much slower. One newer option is electrodialysis, which uses traditional osmosis in the presence of an electric field to move the ions across the membrane. It is much faster than reverse osmosis, but only removes the salt, not any particulate matter or bacteria. Now, Daosheng Deng of MIT and his colleagues have developed a version of electrodialysis that removes all three. A porous glass filter added near the cathode removes all dirt larger than 0.5 µm and 99% of the bacteria in the water. The next step will be to scale the project up to determine whether it is cost-efficient at usable volumes of production.