How does high pH affect water disinfection?

High pH levels in water can significantly impact disinfection processes, particularly when chlorine is used as a disinfectant. At elevated pH levels, the effectiveness of chlorine diminishes, leading to lower disinfection efficacy. This is primarily because chlorine exists in various forms in water, depending on the pH. At higher pH levels, a greater proportion of chlorine is present as hypochlorite (OCl-), which is less effective at killing pathogens compared to hypochlorous acid (HClO), the more potent form of chlorine that predominates at lower pH levels.

Therefore, high pH can create an environment that is less favorable for effective disinfection, hampering the ability to eliminate harmful microorganisms. This can lead to compliance issues with water quality standards and increased health risks. Understanding the relationship between pH and chlorine effectiveness is crucial for water treatment operations to ensure safe drinking water.