What does the term "chlorine residual" refer to?

The term "chlorine residual" specifically refers to the amount of chlorine that remains in water after the disinfection process has occurred. This residual is important because it indicates that there is still some level of chlorine present to continue disinfecting and protecting the water from microbial regrowth as it travels through the distribution system to consumers.

Monitoring chlorine residual is critical in water treatment as it helps ensure that the water remains safe for consumption throughout its journey from treatment plants to taps. An adequate chlorine residual can prevent the growth of bacteria and pathogens that may enter the water system after initial treatment.

Understanding chlorine residual is essential for water quality management, as it influences both the effectiveness of disinfection and the safety of drinking water. The amount of chlorine used initially or during treatment is different from the residual, as it may not all remain in the water after the disinfection process. The time it takes for chlorine to dissipate is also a separate consideration and pertains to water treatment procedures and distribution practices rather than the measure of residual chlorine itself.