An international team of researchers led by associate professor Jim Malley at the University of New Hampshire is testing the use of ultraviolet light for drinking water purification on a very large scale for the first time at municipal drinking water systems around the world. Shown from left to right are Bryan Townsend, Aaron Margolin, Amy Moore, Jim Malley and Laurel Passantino. (UNH Photo by Gary Samson)
Click here to enlarge imageUnlike chlorine and current filtration methods, the new UV technology can zap emerging dangerous pathogens, such as Cryptosporidium, which contaminated Milwaukee's drinking water supply in 1993, killing 110 and sickening 400,000. "Cryptosporidium is hard to filter out, and chlorine has no effect on it," notes Malley. "If you put it in a bottle of bleach for a week and take it out, it still makes a mouse sick."
UV disinfection involves the generation of photons of light energy in the "germicidal wavelengths" of approximately 200 to 300 nanometers by commercially available mercury vapor lamps, which are similar to the fluorescent lights used in most offices.
UV treatment is one of several technologies the Environmental Protection Agency will recommend to help communities meet new, more stringent drinking-water standards due out in 2002. UV light is not only effective, but also very efficient. It can disinfect water at about one-tenth the cost of other treatment methods, according to Malley, in part because the equipment is so small.
A UV light facility for New York City, which provides 1.6 billion gallons of water a day, would take the space of one football field. An ozone facility, by comparison, would require 1000 times more space. The city, which will need to significantly upgrade its water treatment to meet the new EPA regulations, would save literally billions of dollars on the installation of a UV facility, Malley notes.
Although the technology has been used in Europe for about 75 years, UV treatment of drinking water was introduced in this country in 1992, as a result of UNH research directed by Malley, who is now president of the International UV Association. Today there are about 50 systems in the United States, with the largest serving 30,000 residents in Fort Benton, Montana.
In addition to testing UV disinfection on a larger scale, the three-year project will include research at UNH and in Southern California to establish the doses of UV light needed to inactivate pathogens such as Adenovirus, Astrovirus, and E. coli 0157-H7, which has contaminated water as well as ground beef and other foods.
What Malley describes as his "UV dream team" includes UNH microbiologist Aaron B. Margolin plus researchers from Lyonnaise des Eaux-CIRSEE in Paris, Carollo Engineers in Boise, Idaho, and Duke University. The group was one of four international teams that competed for the $1.3 million grant from the American Water Works Association Research Foundation in collaboration with the Water Environment Research Foundation and the EPA. During the next three years, the UV systems will be tested in Sydney, Atlanta, Salt Lake City, Austin, Phoenix, St. Louis, California's Santa Clara Valley, and the Metropolitan Water District of Southern California.
Malley's research is conducted under the auspices of the UNH Water Technology Treatment Assistance Center, one of eight federally funded centers in the country. Funding for the UNH center was secured by Senator Bob Smith.
