What is the required detention time for disinfecting a water storage tank with hypochlorites at a free chlorine level of 10 mg/L?

The required detention time for disinfecting a water storage tank when using hypochlorites at a free chlorine level of 10 mg/L is 24 hours. This duration is essential to ensure that the chlorine has sufficient time to effectively neutralize any pathogens or contaminants present in the water.

Disinfection is a critical step in water treatment, as it helps eliminate harmful microorganisms that could pose health risks to consumers. The effectiveness of chlorine as a disinfectant relies not just on the concentration, but also on the contact time it has with the water. The longer the water remains in contact with the disinfectant, the more effective it is at achieving a high level of disinfection.

For chlorination at 10 mg/L, guidelines typically specify a minimum detention time of 24 hours to ensure comprehensive disinfection. This timeframe strikes a balance between operational efficiency and regulatory compliance, ensuring safe drinking water while minimizing the risk of chlorine byproduct formation.

Understanding this standard helps water distribution operators effectively manage their disinfection processes and maintain water quality for public health protection.