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Researchers at the University of Delaware have developed an inexpensive, nonchlorine-based technology that can remove harmful microorganisms, including viruses, from drinking water.
UD's patented technology, developed jointly by researchers in the College of Agriculture and Natural Resources and the College of Engineering, incorporates highly reactive iron in the filtering process to chemically eliminate a host of pathogens, such as E. coli and rotavirus.
The new technology could improve the safety of drinking water around the world, particularly in developing countries. According to the World Health Organization (WHO), over a billion people, one-sixth of the world's population, lack access to safe water supplies.
Four billion cases of diarrheal disease occur worldwide every year, resulting in 1.8 million deaths, primarily infants and children in developing countries. 88 percent of this disease is attributed to unsafe water supplies, inadequate sanitation and hygiene.
Pei Chiu, an associate professor in UD's Department of Civil and Environmental Engineering, collaborated with Yan Jin, a professor of environmental soil physics in UD's plant and soil sciences department, to develop the technology. They then teamed up with virologist Kali Kniel, an assistant professor in the animal and food sciences department, who has provided assistance with the testing phase.
The researchers told the University of Delaware Daily that viruses are difficult to eliminate in drinking water using current methods because they are smaller than bacteria, highly mobile, and resistant to chlorination, which is the dominant disinfection method used in the United States.
The elemental or “zero-valent” iron (Fe) used in the technology is widely available as a byproduct of iron and steel production, and it is inexpensive, currently costing less than 40 cents a pound (~$750/ton). Viruses are either chemically inactivated by or irreversibly adsorbed to the iron, according to the scientists. The new technology removes 99.999 percent of viruses.
The elemental iron also removes organic material, such as humic acid, that naturally occurs in groundwater and other sources of drinking water. During the disinfection process, this natural organic material can react with chlorine to produce a variety of toxic chemicals called disinfection byproducts.
Kniel noted that the UD technology could also have applications in agriculture. Integrated into the wash-water system at a produce-packing house, it could help clean and safeguard vegetables, particularly leafy greens like lettuce and spinach, as well as fruit.
The Centre for Affordable Water and Sanitation Technology in Calgary, Canada, is currently exploring use of the UD technology in a portable water treatment unit. Since 2001, the registered Canadian charity has provided technical training in water and sanitation to more than 300 organizations in 43 countries of the developing world.