Full Description

Because of an increasing need to balance health risks for pathogen control and disinfection byproduct(DBP) formation in water supplies, utilities are forced to closely examine and optimize their disinfectionpractices. The authors provide a simple mechanistic model to predict total trihalomethane (TTHM)and the sum of nine haloacetic acids (HAA9) formation based on chlorine demand. To evaluate thismodeling approach, eight Missouri surface waters (raw and alum-treated) were used in DBPformation and chlorine decay kinetic studies. A parallel first-order reaction model was used to fit thechlorine decay data, and the model coefficients were used to predict THM and HAA formation.Yield coefficients for TTHMs and HAA9 were obtained from fitting the DBP kinetic data. On average,the TTHM and HAA9 yield coefficients for all raw surface waters tested were about 40 ug TTHM/mgCl2 and 25 ug HAA9/mg Cl2 consumed, respectively. In waters subjected to alum coagulation, theaverage TTHM and HAA9 yield coefficients were 30 ug TTHM/mg Cl2 and 17 ug HAA9/mg Cl2consumed, respectively. The DBP predictive model introduced in this study provided a simple,reliable basis to evaluate treatment options by focusing on chlorine demand. This model can bereadily calibrated to local conditions. Includes 23 references, tables, figures.

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Edition: Vol. 94 - No. 10 Published: 10/01/2002 Number of Pages: 11File Size: 1 file , 250 KB