To thelong list of great ideas gone bad, add the uv Waterworks―a simple, cheap device to purify filthy drinking water in poor countries. Ashok Gadgil started with the best of intentions. A senior scientist at Lawrence Berkeley National Laboratory, he watched in horror as a cholera epidemic swept through his native India a decade ago. After two years of tinkering he created a 16-pound version of the ultraviolet water sterilizers that are commercially available in the U.S. for home wells with contamination problems. The 254- nanometer light kills the hardy waterborne polio virus, rotavirus (which causes vomiting, diarrhea and dehydration), the bacterium that causes cholera, the virus that gives rise to hepatitis A, and cysts of cryptosporidium (a nasty parasite). UV Waterworks' disinfection was three times as strong as that required by the World Health Organization, giving a dose of 120 millijoules per square cen- timeter to water 4 centimeters deep. "I wanted to give back to give to the society I came from some fruit of the knowledge I learned in the U.S.," says the 52-year-old inventor. i
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