Why is maintaining a proper pH important in water treatment?

Maintaining a proper pH in water treatment is vital because it directly influences the solubility and effectiveness of chlorine, a common disinfectant used in the process. Chlorine functions optimally at a specific pH range, typically between 6.5 and 8.5. Outside of this range, the form of chlorine may change; for instance, at lower pH levels, chlorine exists mainly as hypochlorous acid, which is more effective at killing pathogens. Conversely, at higher pH levels, chlorine is more likely to exist as hypochlorite ion, which is less effective as a disinfectant. Therefore, by maintaining the proper pH, water treatment facilities ensure that chlorine remains effective in controlling harmful microorganisms, thereby ensuring safe drinking water.

While taste, color, and other factors can be influenced by pH levels, the primary concern in treatment is the effectiveness of chlorine disinfection for ensuring water safety.