UV and UV/H2O2 for Disinfection and Nitrosamines Treatment: An Update

The occurrence of chemical and microbiological pollutants in water has been documented. At the same time, increased water scarcity is driving interest in water reuse. Water providers are increasingly utilizing reuse, including Indirect Potable Reuse, to augment regional water supplies. Ultraviolet (UV) light for disinfection and UV plus hydrogen peroxide, are key components of the treatment processes being utilized for these applications.A number of water reuse and IPR projects around the world are in progress including Melbourne Australia's Eastern Treatment Plant and the Orange County Water District's Groundwater Replenishment System. These projects utilize advanced treatment including membranes, UV, or UV with hydrogen peroxide (UV-oxidation) to produce safe water. Water providers use UV disinfection to act as a barrier to chlorine-resistant organisms, while reducing reliance on chemical disinfectants. A sustainability analysis was conducted that illustrates that UV has a smaller environmental impact than chlorine and ozone. Further, water providers use UV-oxidation to act as a barrier to nitrosamines (particularly N-nitrosodimethylamine [NDMA]), a variety of pharmaceutical compounds and various endocrine-disrupting compounds. Full-scale demonstration testing illustrated that NDMA is successfully removed with UV-oxidation.