What is the required free chlorine residual in solutions made from dry fluoride chemicals?

The required free chlorine residual in solutions made from dry fluoride chemicals is set at 10 mg/l. Maintaining a free chlorine residual at this level is crucial for adequate disinfection and maintaining water quality, especially in systems where fluoride is added to prevent dental caries.

Chlorine acts as a disinfectant and is essential for the elimination of pathogens in water. The specified level ensures that sufficient residual chlorine is present in the water, which can help prevent bacteria regrowth and maintain the safety of the water supply.

Other levels, such as 5 mg/l or 15 mg/l, may not provide the necessary disinfection capacity needed in combination with the chemical properties of fluoride compounds. A free chlorine residual that is too low could lead to insufficient disinfection, while a level that is excessively high could result in taste or odor issues in the water. Therefore, 10 mg/l strikes a critical balance, ensuring both safety and palatability.