In this video the seven stages of drinking water: pre-treatment, coagulation & flocculation, sedimentation, filtration, disinfection, supplemental treatment, storage & distribution are introduced. Each of these steps is described in more details to understand why these steps are needed to clean the water for drinking. With the help of chemical reactions, the purpose of coagulation is explained. The various filtration mechanisms and their effectiveness in water purification is explained. Why is chlorine is used to treat drinking water? The definition of chlorine demand and residual chlorine are clarified. Finally, which micro-organism are effectively inactivated by adding chlorine and which ones are more resistant to chlorination is explained.
