What process is described as adding chlorine to water until the chlorine demand is satisfied?

The process of adding chlorine to water until the chlorine demand is satisfied is referred to as breakpoint chlorination. This process is crucial in water treatment as it involves adding chlorine to achieve two primary goals: to first react with various contaminants and reactive compounds in the water, and then to provide a residual amount of chlorine that can effectively disinfect the water.

In breakpoint chlorination, an initial amount of chlorine is added to overcome the demand posed by substances such as ammonia, organic matter, and other chlorine-consuming compounds. Once all these compounds are reacted with chlorine, additional chlorine can then be applied to achieve a “breakpoint.” At this point, the water will have a free chlorine residual sufficient for effective disinfection. This process ensures that enough chlorine remains in the water to kill pathogens and maintain the quality of the treated water.

This method is particularly important in ensuring that the water is not only treated effectively but also safe for consumption, as it guarantees a sufficient level of chlorine is available after meeting the combined chlorine demand. The understanding of breakpoint chlorination is vital for water operators in managing water treatment processes efficiently.