Contact period of chlorination ?
Contact period for chlorination is one hour. The presence of free residual chlorine for a contact period of one hour is necesary to kill pathogens. The residual chlorine is 0.5 mg/L.Parks textbook of preventive and social medicine.K Park. Edition 23.Pg no: 715
1 hour
30 minutes
1 1\/2 hour
2 hours
Environment and health