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THE EFFECT OF CHLORINE DEMAND ON INACTIVATION RATE CONSTANT
Citation:
SIVAGANESAN, M., GENE W. RICE, AND N. ADCOCK. THE EFFECT OF CHLORINE DEMAND ON INACTIVATION RATE CONSTANT. doi:10.2166/aqua.200, J K Edzwald (ed.), JOURNAL OF WATER SUPPLY: RESEARCH AND TECHNOLOGY - AQUA. IWA Publishing, London, Uk, 57(3):165-170, (2008).
Impact/Purpose:
to provide information
Description:
Ct (disinfectant concentration multiplied by exposure time) values are used by the US EPA to evaluate the efficacy of disinfection of microorganisms under various conditions of drinking water treatment conditions. First-order decay is usually assumed for the degradation of a disinfectant chemical such as chlorine, ozone or chloramine in drinking water. The concentrations of these disinfectants are usually measured at the initial and final contact times, and Ct values are estimated by the area under the first-order decay curve. In this inactivation study, residual chlorine was measured at least two times in between initial and final contact times. The residual chlorine concentration-time profile shows that a second-order decay model fit was better than a first-order decay model fit. Traditionally Ct is treated as a constant in estimating the rate constant of the simple Chick-Watson inactivation kinetics model. As Ct is estimated it is subject to estimation error. To account for this error, the parameters of the chlorine decay and the inactivation models were estimated simultaneously.
