New Energy-Efficient Water Purification Process Developed

A scientist at Yale University has developed a new energy-efficient technology for drawing fresh water from nonpotable water sources.

Using a process called "forward osmosis," the system exploits the natural tendency of water to diffuse through a semipermeable membrane. It draws pure water away from its contaminants into a solution of concentrated salts, which are then easily removed by a low heat treatment. The system requires only about one-tenth the electrical energy used by traditional desalinization techniques. Yale University is commercializing this desalinization technology through a private company called Oasys.

Another similar technology is being developed into what is called an "osmotic heat engine" to more efficiently generate electricity using low-temperature heat sources. In a process called pressure-retarded osmosis, a solution is held under high pressure while water moves into the solution via osmosis. The pressure of the expanding volume of solution is then released through a turbine to generate electrical energy. The costs of producing electricity via this method can be competitive, as industrial waste heat can be used to fuel the process.

These results were published in the December issue of Environmental Science & Technology.

Source: ScienceDaily; Photo: Yale University