Disinfection byproducts (DBP) pose a major problem for the drinking water industry due to their carcinogenic nature and formation when natural organic matter (NOM) reacts with chlorine. This study investigates the formation of individual DBP compounds within waters containing various NOM characteristics. Water from the Iowa River was concentrated through reverse osmosis and NOM fractions were isolated using resin separation. In addition, waters from the city of Barberton water treatment plant were collected prior to and subsequent to coagulation. Experiments were conducted on each water source under variable chlorine doses and pH, with and without the presence of model iron oxides. The purpose of this study was to investigate the role of NOM and the surrounding environment on DBP formation and develop measures for the prediction of byproduct formation.
Fluorescence excitation-emission matrices (EEM) of NOM were quantified and characterized using fluorescence regional integration (FRI) and parallel factor analysis (PARAFAC). Changes in FRI of five operationally defined regions coupled with chlorine consumption showed strong linear relationships to the formation of chloroform (CHCl3), dichloroacetic acid (Cl2 AA), and trichloroacetic acid (Cl3AA). Stepwise regression of fluorescence regions revealed the use of only one region coupled with chlorine consumption to predict DBP formation, yet this region varied depending upon the individual compound assessed. This technique provides an effective tool that can utilize both chlorine reactivity and functional group properties of the NOM to predict DBP formation.
PARAFAC analysis of EEM yielded three statistically significant components providing relative concentrations of fluorophores within each sample. While this technique has previously been used for NOM characterization, it has yet to be utilized to assess DBP formation. Multi-factor linear regression of select component scores showed strong linear relationships to individual DBP compounds providing insight to organic compound characteristics responsible for DBP formation. These finding suggest that fluorophore component scores may be an effective parameter used to estimate DBP precursor concentration. In doing so, water plants can evaluate the fluorescence components and assess the effects of various treatment schemes on NOM, providing a more specific approach to precursor removal and a better understanding of DBP formation.
|School:||The University of Akron|
|School Location:||United States -- Ohio|
|Source:||DAI-B 79/08(E), Dissertation Abstracts International|
|Subjects:||Civil engineering, Environmental engineering|
|Keywords:||Chlorine, Dbp formation, Fluorescence eem, Parallel factor analysis|
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