The potable water is prepared from turbid surface water

The potable water is prepared from turbid surface water by adopting the following treatment sequence.

1. Turbid surface water → Coagulation → Flocculation → Sedimentation → Filtration → Disinfection → Storage & Supply
2. Turbid surface water → Disinfection → Flocculation → Sedimentation → Filtration → Coagulation → Storage & Supply
3. Turbid surface water → Filtration → Sedimentation → Disinfection → Flocculation → Coagulation → Storage & Supply
4. Turbid surface water → Sedimentation → Flocculation → Coagulation → Disinfection → Filtration → Storage & Supply

Coagulation – flocculation process is always followed by Sedimentation and then filtration. Disinfection is the last process.