"We knew that iron had been used to treat a variety of pollutants in groundwater, but no one had tested iron against biological agents," Chiu said. So the two researchers decided to pursue some experiments.
With partial support from the U.S. Department of Agriculture and the Delaware Water Resources Center, through its graduate fellowship program, the scientists and their students began evaluating the effectiveness of iron granules in removing viruses from water under continuous flow conditions and over extended periods. Two bacteriophages--viruses that infect bacteria--were used in the initial lab studies.
Since then, Kniel 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.
"In 20 minutes, we found 99.99 percent removal of the viruses," Chiu said. "And we found that removal of the viruses got even better than that with time, to more than 99.999 percent."
The elemental iron also removed 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.
Applications in agriculture and food safety
Besides helping to safeguard drinking water, the UD technology may have applications in agriculture.
Integrated into the wash-water system at 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,
Source:University of Delaware