Narrator: This is Science Today. About 75 percent of wastewater treatment plants around the country disinfect water using chlorine, and about 20 percent use ultraviolet, or UV, disinfection systems that use mercury lamps in direct contact with water. The mercury lamps are not only expensive to dispose of, but they also need to be frequently cleaned to remove algae from the water contact.
Younis: Moreover, if you put lamps or indeed if you put anything within flowing water, you cause hydraulic losses — hydraulic losses mean that to get the same amount of water to flow within a given period of time, you'll need more energy.
Narrator: As an alternative, Bassam Younis, a civil and environmental engineer at the University of California, Davis, has developed a novel technology called UltraV.
Younis: Our particular design, we have a reactor in which the flow is rotated, it's swirling. The lamp is located on the outside, so the pathogens basically come to the lamp as they rotate. So, it's efficient, it avoids contact between the water and the lamps, it reduces a great amount of hydraulic losses.
Narrator: For Science Today, I'm Larissa Branin.