Water Desalination Made Cheaper With Oasys Water's New Technology

So far, there’s been plenty of water in the oceans and seas, but that’s salty and undrinkable. Oasys Water, a company specialized in desalination, comes with a solution to the scarcity of water in some regions and also cuts the costs for producing it.

The newly-built Boston facility has come online this week and they are planning to actually sell their systems by December 2011.

The Oasys Water solution to desalination relies on a blend of the two techniques currently used: evaporation or reverse osmosis (when water is forced at a high pressure through a salt-filtering membrane). Their solution relies on a more porous membrane that has water on one of its sides and a solution made from ammonia and carbon dioxide (whose formula has been developed at Yale) on the other side (in high concentrations).

The process of filtering the water is simple and straightforward in their technology, through ordinary (forward) osmosis. Water gets sucked in through the membrane towards the more concentrated solution, but leaves its salty part in the osmotic filter. Then, by heating the resulted solution at 40 to 50 degrees, the carbon dioxide and ammonia evaporate leaving pure, drinkable water. The other two get captured and reused.

“The cost will be low enough to make aqueduct and dam projects look expensive in comparison,” says Oasys cofounder and CTO Robert McGinnis, who invented the company’s core technology. The process could also require substantially less power than other desalination options. “The fuel consumption and carbon emissions will be lower than those of almost any other water source besides a local lake or aquifer,” he says.

McGinnis also suggests that future water desalination plants using Oasys Water technology could be placed near power plants, where they could benefit from wasted heat. Currently, desalination plants do sit near power plants, but they usually need extra energy to force water through the dense reverse-osmosis membranes. Additionally, there won’t be any need for expensive equipment such as high-pressure pipes, making the produced water even cheaper.

Desalinating water is regularly an energy-intensive process. Using one tenth the energy required for a classic plant, Oasys Water’s osmosis system will surely account for many thousands of tons of saved carbon dioxide yearly. The solution will only be worthy for cities like Los Angeles, and less for agricultural users, who use large quantities of water (80% of the total consumed), but who also live near freshwater sources.