Georgia Drinking Water Laboratory Analyst Practice Test

Total chlorine residual is a key measurement in water quality testing, particularly in drinking water treatment processes. It is composed of two specific components: free chlorine and combined chlorine. Free chlorine refers to the chlorine that is present in water as hypochlorous acid and hypochlorite ions, which are effective at disinfecting and killing pathogens. This component is actively available for disinfection purposes.

Combined chlorine, on the other hand, results from the reaction of chlorine with ammonia and organic nitrogen compounds in the water, forming chloramines. Combined chlorine is less effective as a disinfectant compared to free chlorine, but it still contributes to the overall chlorine residual in the water.

The significance of understanding these two components lies in their roles in maintaining water safety and the overall quality of drinking water. Monitoring both free and combined chlorine allows water treatment facilities to ensure that adequate disinfection levels are maintained while minimizing the formation of potentially harmful byproducts.

Given this explanation, the understanding of chlorine composition is crucial for maintaining effective water treatment operations and ensuring public health through safe drinking water.