Whether turning on a tap to fill a container or drinking from a fountain, people in developed countries normally have readily available and inexpensive access to a clean, safe water supply.That is not the case for more than 800 million people in developing countries, according to Ernest “Chip” R. Blatchley III, professor of civil engineering and environmental and ecological engineering at Purdue Univ. Blatchley and other researchers are working to provide safe water supplies for these people by using ultraviolet radiation from the sun to purify water.
“Millions of people in developing countries do not have readily available water, or they become sick because of the water they drink,” he said. “People in these countries may not have the infrastructure or financial resources to clean the water, deliver it and keep it clean until it’s used. Common problems include microbial pathogens, which are largely associated with human and animal waste.”Blatchley and Bruce Applegate, associate professor of food science and biological sciences at Purdue, Cultural factors in construction and use, have developed prototypes of a water disinfection system to take advantage of UV radiation from the sun, which is plentiful in many areas where clean water is lacking.”If you take a global view of people who have little or no access to safe water, you’ll see that most live close to the equator,” Blatchley said. “Bruce, student researchers and I have created prototypes that disinfect water by amplifying and concentrating solar UV radiation, which is abundant in equatorial and near-equatorial nations.”
Applegate said the Purdue water disinfection system pumps water through a UV-transparent pipe placed on a parabolic reflector.”The shape of the reflective mirror concentrates the sun’s UV rays so the radiation inside the pipe is more intense than outside,” he said. “The radiation damages the DNA in microorganisms. When this is done, the microbes can no longer grow and the water is safe.”Solar UV systems have been developed by other groups. The Purdue system, however, uses different materials than others.