A process developed by engineers at Massachusetts Institute of Technology produces clean water at relatively low cost. After further development, the process could also lead to inexpensive, efficient desalination plants for communities in the developing world, the researchers say.
The method is a variation of the standard distillation process, in which salty water is vaporized and then condenses on a cold surface; the salt separates out during evaporation. But this process is energy-intensive — and therefore costly — because all the water must be heated to the boiling point, while the condensing surfaces must be kept cold.
In the new process, water well below the boiling point is vaporized by direct contact with a carrier gas; the moist air is subsequently bubbled through cooler water where the purified vapor condenses. But the temperature difference between the warm and cool water is much less than in conventional dehumidifiers, and the surface area provided by the small bubbles is much greater than that of a flat condenser surface, leading to a more efficient process.
Also: A water purification system received top honors in the 2012 "Create the Future" design contest.
