Bayesian Statistical Modeling of Disinfection Byproduct (DBP) Bromine Incorporation in the ICR Database

• Published in: Environmental science & technology 2010-02, Vol.44 (4), p.1232-1239
• Main Authors: Francis, Royce A, VanBriesen, Jeanne M, Small, Mitchell J
• Format: Article
• Language: English
• Subjects: Acids; Applied sciences; Bayes Theorem; Bayesian analysis; Bromine - chemistry; By products; Characterization of Natural and Affected Environments; Chemical elements; Chlorine; Disinfectants - chemistry; Disinfection & disinfectants; Drinking water; Drinking water and swimming-pool water. Desalination; Environmental Monitoring; Environmental science; Exact sciences and technology; Models, Statistical; Pollution; Statistical methods; Temperature; Trihalomethanes - chemistry; Water treatment and pollution
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es9028606

Statistical models are developed for bromine incorporation in the trihalomethane (THM), trihaloacetic acids (THAA), dihaloacetic acid (DHAA), and dihaloacetonitrile (DHAN) subclasses of disinfection byproducts (DBPs) using distribution system samples from plants applying only free chlorine as a primary or residual disinfectant in the Information Collection Rule (ICR) database. The objective of this study is to characterize the effect of water quality conditions before, during, and post-treatment on distribution system bromine incorporation into DBP mixtures. Bayesian Markov Chain Monte Carlo (MCMC) methods are used to model individual DBP concentrations and estimate the coefficients of the linear models used to predict the bromine incorporation fraction for distribution system DBP mixtures in each of the four priority DBP classes. The bromine incorporation models achieve good agreement with the data. The most important predictors of bromine incorporation fraction across DBP classes are alkalinity, specific UV absorption (SUVA), and the bromide to total organic carbon ratio (Br:TOC) at the first point of chlorine addition. Free chlorine residual in the distribution system, distribution system residence time, distribution system pH, turbidity, and temperature only slightly influence bromine incorporation. The bromide to applied chlorine (Br:Cl) ratio is not a significant predictor of the bromine incorporation fraction (BIF) in any of the four classes studied. These results indicate that removal of natural organic matter and the location of chlorine addition are important treatment decisions that have substantial implications for bromine incorporation into disinfection byproduct in drinking waters.