How is chlorine dosage calculated?

Chlorine dosage calculation is a critical aspect of water treatment and is primarily determined by both the demand and the residual. The demand refers to the amount of chlorine needed to react with various substances in the water that consume chlorine, such as organic matter, ammonia, and bacteria. The residual is the amount of chlorine that remains after the demand has been satisfied and is available for ongoing disinfection.

To effectively ensure safe and treated water, the chlorine dosage must be sufficient to cover the demand imposed by the water and provide a measurable residual that indicates effective disinfection. Therefore, the total chlorine dosage is calculated by adding the chlorine demand to the desired residual level. This ensures that all necessary reactions are completed, and there is enough free chlorine remaining to provide continued disinfection throughout the distribution system.

Considering this method, the correct approach to chlorine dosage calculation involves both the demand and the residual to achieve optimal water treatment results.