Which factor has the most effect on chlorine efficiency in water treatment?

The pH level is critical in determining chlorine efficiency in water treatment because chlorine operates optimally within a specific pH range. When the pH of water rises above 7.5, the effectiveness of chlorine as a disinfectant decreases. This is due to the fact that chlorine exists in two forms in water: hypochlorous acid (which is the active form that kills pathogens) and hypochlorite ion. As the pH increases, the proportion of hypochlorous acid decreases, diminishing the overall disinfection capability of chlorine.

Additionally, maintaining the pH within the ideal range (between 7.2 and 7.8) ensures maximum effectiveness of chlorine in sanitizing the water. Therefore, understanding and controlling the pH level is essential for maintaining water quality and ensuring the efficient use of chlorine in treatment processes.

Other factors such as temperature and water chemistry do also influence chlorine efficiency, but pH directly affects the chemical form of chlorine available for disinfection, making it the most significant factor in this context. Water depth, while it can impact other aspects of water treatment, does not directly affect the efficiency of chlorine as a disinfectant.