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Monday, February 26, 2007

Elemental water treatment could save millions of lives

University of Delaware researchers announced the development of an inexpensive, non-chlorine-based technology that removes 99.999% of microorganisms, including viruses, from drinking water. The process incorporates highly reactive iron to deliver a chemical “knock-out punch” to a host of notorious pathogens including E-coli and rota virus.

The discovery promises to dramatically improve the safety of drinking water around the globe, 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.

Four billion cases of diarrheal disease occur worldwide each year, resulting in 1.8 million deaths, primarily infants and children in developing countries. Eighty-eight percent of these deaths are attributable to unsafe water supplies, inadequate sanitation and hygiene.

“What is unique about our technology is its ability to remove viruses, the smallest of the pathogens, from water supplies,” said Pei Chiu, an associate professor in UD's Department of Civil and Environmental Engineering.

Chiu collaborated with Yan Jin, professor of environmental soil physics in UD's plant and soil sciences department, to develop the technology. They then sought the expertise of virologist Kali Kniel, an assistant professor in the animal and food sciences department, who has provided critical assistance with the testing phase.

Viruses are difficult to eliminate in drinking water using current methods because they are far smaller than bacteria, highly mobile, and resistant to chlorination, which is the dominant disinfection method used in the United States. By using elemental iron (a byproduct of steel production) in the filtration process, the team was able to remove viral agents from drinking water at very high efficiencies. The elemental iron is inexpensive, costing less than 40 cents a pound. 99.999% of the virus organisms are either chemically inactivated or irreversibly adsorbed to the iron.

The team of researchers has been documenting the technology's effectiveness against human pathogens including E. coli 0157:H7, hepatitis A, norovirus and rotavirus. Rotavirus is the number-one cause of diarrhea in children, according to Kniel.

The treatment 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.

“Our iron-based technology can help ensure drinking-water safety by reducing microbial pathogens and disinfection byproducts simultaneously,” Chiu noted.

Besides helping to safeguard drinking water, the UD technology may have applications in agriculture. Integrated into the wash-water system of a produce-packing house, it could help clean and safeguard fresh and “ready to eat” vegetables, particularly leafy greens like lettuce and spinach, as well as fruit, according to Kniel.

“Sometimes on farms, wash-water is recirculated, so this technology could help prevent plant pathogens from spreading to other plants,” she said.

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