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AWWA WQTC71523
- Chloramines Dosing Kinetics in the Absence of a Prechlorination Step: Impact on Disinfectant Stability and DBP Formation
- Conference Proceeding by American Water Works Association, 11/01/2009
- Publisher: AWWA
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This powerpoint presentation begins by providing a brief overview of nitrification and a chloramines dosing strategy to control nitrification. The problem statement asks, "Can excess Cl<sub>2</sub> be added to achieve the targetresidual at a 5:1 Cl<sub>2</sub>:NH<sub>3</sub>-N ratio?" A case study of Trinity River water is presented that included previous dosing at a 5:1 applied ratio that resulted in freeammonia in the delivery pipe, and a reduction in NH<sub>3</sub> could save money, but breakpoint rxnsare a concern. The experimental methodology included: bench-scale experiment;Cl<sub>2</sub> and NH<sub>3</sub> added to Trinity River water in chlorinedemand-free amber glass bottles (250 mL); duplicates conducted for experiments zero (0) and 4; total and free chlorine measurements by DPDmethod (Hach 8167 and 8021); and,total ammonia by Salicylate Method (Hach 8155). Raw water characteristics are presented, along with chlorine demand in Trinity River water, minimal breakpoint reactions, and disinfection byproducts results. Includes tables, figures.