Researcher's Work Developed into Advanced Water Filters for India

An Auburn University chemistry professor's research is leading to safer drinking water in India through advanced, longer-lasting water filters.

Professor Dave Worley's N-halamine technology is the basis for the in-home filters that HaloSource Inc. introduced on March 1 in Bombay, India. The company, established in 1998 on the potential of Worley's discoveries, pays royalties to the university through a technology transfer agreement.

"Many millions of people in India do not have sanitized drinking water, so there is a great need for this filter," said Jeff Williams, senior vice president and cofounder of HaloSource, which is partnering with India's Eureka Forbes company. "We test-marketed filters in hundreds of homes in India last year and are excited about the positive response."

The filters contain polystyrene beads that hold oxidative chlorine or bromine atoms for long periods of time and that can be easily refurbished -- the results of Worley's N-halamine chemistry. He has received 30 patents in the course of discovering this process that binds the atoms to the surface of various materials.

Worley, an Auburn faculty member for 33 years, won the university's Creative Research and Scholarship Award last fall for his development of the technology. "It has many potential applications that could improve health around the world, especially in less-developed areas," Worley said.

To activate the filters, chlorinated or brominated water is passed through them to anchor the chlorine or bromine atoms to the beads. When untreated water with bacteria, mold or virus cells pass through the filter, the cells pick up the atoms, which sink into the cell walls and kill them. The filters can be refurbished periodically just by running chlorinated or brominated water through them again.

"The use of chlorine in city treatment plants will kill bacteria only for a short time period," he said. "This may be several hours inside dark pipes, from the water treatment plant to the faucet. Sunlight reduces effectiveness even more, which is why chlorine tablets must be continuously added to your swimming pools."

India's water supply gets contaminated during the monsoon season, and it has high levels of calcium and magnesium, causing water hardness about six times greater than in the United States.

Current attempts to disinfect water include putting tablets in a pail of water and stirring and drinking, which does not provide enough water volume and it leaves the water with a bad taste. "Some filters just remove dirt and make the water look clean, but it still contains harmful bacteria," Worley said.

India's cities quickly outgrow the capacity of municipal water systems, so water is primarily provided by street vendors, who pull 1,000-gallon tanks behind tractors and then pump water to roof-top tanks

"In Bombay alone, several million people buy their water off the street. None of it is sanitized," Williams said.

More information about HaloSource is available at

This article originally appeared in the 03/01/2007 issue of Environmental Protection.

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