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, according to the researchers.
Of all the inhabitants of the microbial world, viruses are the smallest--as tiny as 10 nanometers. According to the American Society for Microbiology, if a virus could be enlarged to the size of a baseball, the average bacterium would be the size of the pitcher's mound, and a single cell in your body would be the size of a ballpark.
"By using elemental iron in the filtration process, we were able to remove viral agents from drinking water at very high efficiencies. Of a quarter of a million particles going in, only a few were going out," Chiu noted.
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.
Technology removes 99.999 percent of viruses
The idea for the UD research sprang up when Jin and Chiu were discussing their respective projects over lunch one day.
Since joining UD in 1995, Jin's primary research area has been investigating the survival, attachment and transport behavior of viruses in soil and groundwater aquifers. One of the projects, which was sponsored by the American Water Works Association Research Foundation, involved testing virus transport potential in soils collected from different regions across the United States. Jin's group found that the soils high in iron and aluminum oxides removed viruses much more efficiently than those that didn't contain metal
Source:University of Delaware