Maintaining Distribution System Residuals Through Booster ChlorinationThe goal of this project was to discuss the potential advantages associated with booster disinfection, the kinetics of chlorine decay and trihalomethane (THM) formation under rechlorination conditions, and the use of network hydraulic and water quality models to locate booster disinfection stations and determine their dose characteristics. The following are highlights from the research: A laboratory procedure was proposed for analyzing chlorine decay under simulated booster conditions. An initial set of experiments evaluated disinfectant decay under booster conditions, and found it to be dependent on both the magnitude and time of the boost dose. THM formation under booster conditions showed no long-term reduction for any set of results, indicating THM formation is not solely dependent on disinfectant concentration. In booster chloramination, boosting with chlorine appeared to be very successful at producing and maintaining a low ammonia concentration by recombining with the ammonia formed from chloramine decay. A second-order model, including a reaction component that represents natural organic matter, was developed to describe chlorine decay and THM formation under booster conditions. A method was developed to determine good locations and schedules for multiple booster doses by a systematic evaluation of alternative designs using network models. By exploring the disinfection decay kinetics under rechlorination, and developing methods for booster chlorination systems design, the project results will assist utilities and consultants in making better use of booster disinfection as a residual maintenance approach. Originally published by AwwaRF for its subscribers in 2003 |
Contents
Report Summary | 1 |
Introduction to Booster Disinfection | 7 |
Current State of Practice | 31 |
Copyright | |
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140 Time hours 24 hours 72 hours ammonia concentration analysis average B₁ BDDA booster chlorination booster disinfection booster locations booster station chemical kinetic chloramine Chlorine decay data Chlorine demand data Chlorine Demand mg chlorine dose Cl:DOC Cl:N Conc constant constraints conventional CPLEX data of phase decay and THM decay rate Demand mg Cl₂/L demand study dichloramine disinfectant concentration disinfectant decay disinfectant mass disinfectant residual distribution system dynamics Epanet input file experimental first-order model flow proportional flow rate function Harsha Lake water increased initial dose injector locations keyword Las Vegas linear superposition location model maximum mg/L minimum monitoring node MPS format multiple boost doses network hydraulics nitrification number of booster operating periodic phase IIb pipe reaction rechlorination reduce reservoir residual concentration residual maintenance SCCRWA second-order model solution South Norwalk water Specify station design t₁ tank THM formation water quality models µg/L