September 2, 2005 3:40 PM PDT
Technology may quench thirst for drinking water
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Hurricane cleanup could take months, yearsAugust 31, 2005
The UV-Tube, a low-cost water disinfecting system, is the sort of technology that disaster relief agencies may begin to turn to in the arduous cleanup in the wake of Hurricane Katrina. Other ideas include cheaper systems to test water and, further in the future, new styles of chemical purifiers.
The UV-Tube--which kills germs in water with an ultraviolet light bulb--costs about $70 to put together, can be assembled from components that are fairly easy to find, and can be run off of a solar panel, key in an area where the electrical grid has crumbled.
More importantly, it can process about five liters of water per minute.
"If you run the system throughout the day, you can get drinking water for hundreds of people," said graduate student Micah Lang at the University of California, Berkeley's Renewable and Appropriate Energy Laboratory.
So far, there are no plans to take the tube to the Gulf Coast, but that could change as the cleanup will likely last for months, said Dan Kammen, a professor in the energy and resources group at Berkeley who oversees the project.
The team recently conducted a round of field tests with a solar-powered version of the tube in a tsunami-ravaged village in Sri Lanka and in rural villages in Baja California. The tests have gone quite well, Lang and Kammen said.
"It is a great way to kill most of the pathogens in decaying fecal matter," said Kammen. "The situation looks very much like the tsunami. There are a whole bunch of technologies for this, but most of them are energy intensive."
Water quality generally isn't something most people in western nations think about until it's too late. The topic, however, has begun to percolate inside the tech community as part of the push into using clean technologies such as solar power and alternative energy.
Like with oil, some experts believe that the growing consumption will begin to stress existing supplies of drinkable water. Some start-ups have proposed nanotechnology solutions for purifying water, while others are promoting ways futuristic scenarios in which hydrogen extracted from seawater can power desalination.
For the more immediate future, there are technologies like WaterPoint from Michigan's Sensicore. The handheld device contains a sensor that can test for inorganic impurities, such as ammonia, and test water quality in four minutes, according to director of marketing Uwe Michalak. Conventional equipment takes about an hour.
Sensicore, which recently announced that it has received $12 million in third-round funding, has been testing its products with water utilities and hopes to release its first products in November. A WaterPoint will cost around $2,500, while replacement sensors will go for about $300. Each sensor can test around 30 samples under 14 different parameters each before replacement.
In the aftermath of Katrina, the local agencies first face the challenge of pumping water out of the city and testing the water infrastructure, said Dave Dzombak, professor of civil and environmental engineering at Carnegie Mellon University.
Until that can be done, portions of the city and many of the areas housing refugees will likely have to get water from tankers.
Disinfecting water can be accomplished in a number of ways. One of the most familiar, of course, is boiling. Adding chlorine or small amounts of bleach can also accomplish the task.
Employing UV light to disinfect was actually discovered in 1905. "But it quickly went out of vogue when chlorine was discovered to do the same thing," said Lang. "It was cheaper."
UV light began to make a comeback with water utilities in the 1970s. In the 1980s, Ashok Gadgil at the Lawrence Berkeley National Lab began to experiment with house- and village-level UV purification systems.
This led to the formation of Water Health International, a company that has sold and installed UV systems in Mexico, South Africa and elsewhere.
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