Two Scientists Answer An S.O.S. for a Desalinator for the Shipwrecked
Drinking from the ocean causes deadly dehydration. The new desalinator supplies 1.25 gallons of fresh water hourly, enough to keep 25 people alive. The Navy has spent $200,000 over eight years on the project and expects to have 1,000 desalinators built by 1983. They will cost $500 apiece. Meanwhile, Adamson and Pizzino are working to extend the life of the desalinator pump from 125 hours to 600.
The key to the system is a cellophane-like membrane wrapped around a tube with holes in it. Seawater is forced through the tube by a hand-operated pump at great pressure—between 800 and 1,000 pounds per square inch. The membrane allows water and only a safe 700 parts per million of salt—one-fiftieth of the sea's normal salt content—to pass through. (Potable water from the tap contains 500 parts per million of salt.)
The compact, 10-pound desalinator will replace the bulky cases of fresh water in soda-pop-size cans that the Navy currently puts in lifeboats and life rafts. Survival gear also presently includes a silver compound that removes salt from seawater but leaves a foul taste. The rise in silver prices, however, pushed the cost of the chemical to $1,500 per boat this year. "If the government sold the silver in these kits to industry," notes Pizzino, "they could finance our invention."
Adamson, after studying at Georgia Tech, has been at the lab for 20 years. Pizzino arrived nine years ago after graduating from the University of Maryland. Several thousand man-hours have been devoted to the desalinator project. "It's frustrating not to see our invention put on ships in a hurry," says Pizzino, "but at least now we have a good answer to that Navy slogan, 'What have you done for the fleet today?' "