What is the primary role of residual chlorine in water treatment?

The primary role of residual chlorine in water treatment is killing pathogens. Chlorine is widely used as a disinfectant due to its effectiveness in inactivating various harmful microorganisms, including bacteria, viruses, and protozoa. By maintaining a residual concentration of chlorine in the water, utilities ensure that any pathogens remaining after initial treatment processes are further inactivated as the water travels through the distribution system. This is crucial for protecting public health by preventing waterborne diseases.

While chlorine can have secondary benefits, such as contributing to the overall safety and quality of drinking water, its primary purpose revolves around disinfection. The other options, such as balancing pH, enhancing taste, or reducing color, are not the main focus of residual chlorine’s function in water treatment processes. These actions may be influenced by chlorination but are not the fundamental goal.