Which factor can affect the rate of chlorine disinfection?

The rate of chlorine disinfection is influenced significantly by water temperature and pH. Chlorine efficacy in disinfection is heightened at warmer temperatures because higher temperatures generally enhance the reactivity of chlorine with pathogens. Meanwhile, the pH of the water can affect the species of chlorine present; for instance, in a lower pH environment, more hypochlorous acid (HOCl) is available, which is more effective at disinfecting, compared to hypochlorite ions (OCl-) that dominate at higher pH levels. Therefore, maintaining optimal water temperature and pH is crucial to achieving effective disinfection using chlorine.

While water turbidity levels, presence of heavy metals, and water color can also impact chlorine's disinfection process by interfering with the chlorine or shielding microorganisms, they are not as directly related to the fundamental chemistry of chlorine disinfection as temperature and pH. Turbidity can obscure microorganisms, heavy metals may react with chlorine, and color can absorb wavelengths of light affecting photochemical reactions; however, temperature and pH are primary parameters that dictate the efficiency of the disinfection process itself.