What term describes the amount of chlorine that is consumed or needed in a water treatment system?

The amount of chlorine that is consumed or needed in a water treatment system is referred to as chlorine demand. This term specifically denotes the quantity of chlorine that reacts with contaminants in the water, such as organic matter, ammonia, or other substances that can deplete the available chlorine. Understanding chlorine demand is crucial for water treatment operators, as it helps determine the appropriate dose of chlorine to achieve effective disinfection and maintain adequate residual levels for safety.

Chlorine residual, in contrast, refers to the amount of chlorine that remains in the water after the treatment process, effectively indicating the presence of chlorine available for disinfection purposes. Chlorine capacity and chlorine exposure do not accurately describe the consumption or requirement aspect of chlorine in the treatment process, which focuses on the demand aspect.