Fluorescence And Disinfection Byproducts: Applications In The Drinking Water Field
Beggs, Katherine 1 ; Summers, R. Scott 2 ; McKnight, Diane 3
1 University of Colorado at Boulder
2 University of Colorado at Boulder
3 University of Colorado at Boulder
Dissolved organic matter (DOM) has been identified as the primary carbon precursor in DBP formation. Though much work has been done in relating TOC to DBP formation, the reactive fraction of the TOC responsible for DBP formation is not yet well understood. Five coagulated and filtered waters with varying water quality were used in a bench scale study to test DBP formation under common disinfection schemes; chlorination, booster chlorination, chlorine dioxide/chlorination and chlorination/chloramination. Samples were taken at a number of times after chlorination to investigate formation kinetics, and were analyzed for chlorine residual, THM and HAA concentrations and fluorescence intensity. The coagulated and filtered waters had higher fluorescence indices than the raw water indicating that the larger, more aromatic, "terrestrial" DOM is removed during these treatment processes. The fluorescence intensity of chlorinated waters decreased over time as fluorescing components within the DOM react with chlorine through oxidation, addition and substitution reactions. Parallel factor analysis (PARAFAC) was used to examine changes on the component level using the model developed by Cory and McKnight (2005). PARAFAC results showed that while all components showed a decrease in loading, the contribution of individual components changed over the chlorination period. The redox index (Miller, 2007) was also investigated and showed an increase in oxidation state of the chlorinated water through the change in the redox state of identified quinone components.