New Desalination Technique Yields More Drinkable Water

Sirkar's recently patented system can deliver about 80 liters of drinking water per 100 liters of seawater, he says. A comparable reverse-osmosis system—which relies on pressure to force seawater through a salt-filtering membrane—would reclaim 41 liters from that same amount of saltwater, according to Sirkar. Membrane distillation's advantages include its ability to produce drinking water with very low salinity. In addition, seawater can be distilled at a range of temperatures—from 30 to 100 degrees Celsius—reducing the amount of heat typically needed for desalination, an energy savings, Sirkar says. Prolonged use may decrease a typical membrane's efficiency, but Sirkar says his system adds an ultrathin layer of a highly porous silicone–fluoropolymer coating to extend membrane lifetime. Fluoropolymer—a polymer that contains fluorine atoms—has a high resistance to the solvents, acids and bases found in ocean water. As for the environmental impact of desalination, Sirkar says dumping concentrated brine back into the sea creates a "minimal" disturbance to sea life. He adds, "Seawater is a very large volume with enough turbulence to dilute [the brine] very quickly." Read more: http://j.mp/NcVJ2R

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• Technology
• Desalination

2 Comments

1. A minimum of 5 years - maybe more.

2. While the described membrane distillation technology is showing promise, membrane distillation technology has been the holly grail for over 10 years and a number of similar advancements have been intorduced over this period. My expectiation is that if the claims of the author are confirmed with pilot- and full-scale testing, it will take 5 to 8 years from now until it gets adopted for real-life full-scale applications. The two main challenges with membrane distillation is the need for steam and the productivity and fouling of the membranes. Power plants in highly industrialized countries which lack their own fossil fuil resources do not generate large volumes of waste steam to make memrbane distillation attractive for large-scale desalintion plant applications - these in the Middle East do - so the technology may become more attricative and get full-applicaiton there. While the author mentiones membrane features that address one of the key bottlenecks of exisitng membrane distillation technologies - membrane fouling, the other main bottleneck is its productivity per square meter of membrane area. While RO element productivity has been signficantly enhanced by recent developments in thin-film membrane technologies, the development of commercial membranes for membrane distillation is still in its infancy (and has been for over 10 years now). Only time will tell if the thermal distillation memebrnane technology would advance at fast-enough rate to catch up with the advnaces in RO desalination... Stay tuned.

   1 Comment reply

   1. How close is this technology to market, in the opinion of the original poster?