What is the recommended chlorine dosage when disinfecting a water main using the tablet method?

The recommended chlorine dosage when disinfecting a water main using the tablet method is typically around 50 mg/L. This level is considered effective for achieving proper disinfection throughout the entire system, ensuring that harmful pathogens are adequately eliminated.

Clorination of water mains is a critical procedure in the maintenance of water quality and safety in public water systems. The 50 mg/L dosage strikes a balance between efficacy and safety, allowing for sufficient contact time to eliminate microorganisms without introducing excessive chlorine levels that may result in taste, odor issues, or health concerns associated with high chlorine concentrations.

Other dosages, such as 25 mg/L, may not provide the necessary efficacy for thorough disinfection, especially in systems with heavy biofilm or contamination. Higher dosages like 75 mg/L and 100 mg/L could potentially lead to the formation of harmful chlorinated byproducts, which are regulated and monitored for public health safety. Therefore, the choice of 50 mg/L is based on a combination of scientific guidelines and practical considerations for effective disinfection while minimizing risks.