What is the relationship between water temperature and chlorine residuals when using the CACR method?

When discussing the relationship between water temperature and chlorine residuals as it pertains to the CACR (Chlorine Amperometric Titration with Chlorine Residual) method, the correct designation of mildly inversely correlated is indeed accurate.

As the temperature of water increases, the solubility of chlorine decreases, which means that higher temperatures often lead to lower chlorine residuals. This inverse relationship occurs because warmer water allows chlorine to dissipate more quickly due to increased rates of reaction and chemical degradation, which ultimately results in a reduced concentration of free chlorine over time. Conversely, at lower temperatures, chlorine remains more stable and exhibits higher residual levels.

Understanding this dynamic is crucial for operators and engineers working with water treatment, as it necessitates careful monitoring and adjustment of chlorine doses based on temperature variations to maintain effective disinfection levels in water systems.