ULTRAVIOLET LIGHT INDUCED DISINFECTION BYPRODUCTS: REALITIES AND CHALLENGES

The objective of this study was to investigate the impacts of UV treatment on seven classes of DBPs in water samples chlorinated after UV treatment. Waters were treated with low pressure UV and medium pressure UV at doses of 40, 105 and 140 mJ/cm2. After UV treatment samples were chlorinated at pH 8.6 and held for 3 days before quenching the residual chlorine. Ultraviolet treatment did not substantially change the tendency to form THMs, HAAs, or TOX under the conditions of these tests. No difference could be detected between low pressure UV and medium pressure UV for these DBPs. No conclusions could be made regarding the iodomethanes as their concentrations fell below the method detection limit. Chloropicrin and 1,1,1-trichloropropanone formation increased as a result of medium pressure UV treatment. Low pressure UV did not cause any detectable increase in chloropicrin formation. No conclusions can be drawn about the impacts of low pressure UV on trichloropropanone formation.