Relationships between DBP concentrations and differential UV absorbance in full-scale conditions

Abstract

Differential UV spectroscopy, defined as the difference in UV absorbance spectra before and after chlorination, has shown great potential to predict disinfection by-product (DBP) concentrations at laboratory scale. However, so far, no results have been reported on the full scale application of differential UV spectroscopy in drinking water treatment facilities. The objectives of this study are to determine if relationships can be developed between differential UV absorbance and DBP concentrations, for both regulated and unregulated DBPs, in a full-scale facility and to determine if these relationships vary throughout the year with variations in raw water quality and treatment conditions. The results show that linear and power relationships between differential UV absorbance and DBP concentrations can be developed (0.62 ≤ R² ≤ 0.99), although differences between relationships obtained in lab- and full-scale conditions need further investigation. Finally, the relationships obtained are different from one sampling campaign to another, which raises the question of whether it is possible to determine relationships that are stable enough to be used as adequate feedback on DBP concentrations.

Keywords: Chlorination; Differential UV absorbance; Disinfection by-products; Drinking water; Emerging DBPs.