What is the remaining chlorine called after all chlorine demands have been met?

The term for the chlorine that remains after all chlorine demands, such as reaction with organic material, ammonia, and pathogens, have been satisfied is known as residual chlorine. This residual serves as a measure of the amount of chlorine still available in the water to continue providing disinfection. It is crucial for water treatment processes, as it indicates an ongoing disinfecting capability.

In water quality management, maintaining adequate residual chlorine is essential for ensuring that the water remains safe for consumption throughout the distribution system. This measurement helps operators understand the effectiveness of chlorine treatment and allows for any necessary adjustments based on water quality conditions.

Other terms such as active chlorine, free chlorine, and combined chlorine refer to specific aspects or forms of chlorine in water treatment, but they do not encompass the complete definition of the chlorine remaining after all demands are satisfied. Free chlorine refers specifically to the chlorine available to effectively kill pathogens, while combined chlorine refers to chlorine that has already reacted with organisms or contaminants. Active chlorine is a broader term that might imply effectiveness but doesn't specifically define the remaining quantity. Therefore, the focus on residual chlorine distinctly highlights its role and importance in water treatment processes.