Chemical Engineering - Environmental Engineering - Discussion

Disinfection:

It may be defined as the process of destruction of harmful microorganisms in water. Whereas Sterilization is the process of removal of all types of micro-organisms from the water. Disinfection is an essential minimum treatment requirement for any drinking water and it is the final process in the chain of water purification. Common disinfectants are KMnO4, Ozone(O3), and Chlorine.

Coagulation:
Coagulation is the process in which certain chemicals termed coagulants are added to neutralize the negative protective charge present over the suspended particles so as to increase the opportunity of contact between the neutralized particles and a sticker precipitate resulting in the formation of a bigger size particle.

Sedimentation:
It is the process of removal of suspended particles from the water the entire theory of sedimentation is based upon a single parameter termed Specific gravity.In this process, particles are allowed to settle in the tank due to their own weight and then get removed.

Filtration:
Filtration is most often a policing step to remove flocks or smaller un-sedimented particles. Filtration also removes dissolved organic matter, dissolved minerals, and microorganisms.

Additional Information:

The sequence of the process in the water treatment plant.
Aeration → Coagulation → Flocculation → Sedimentation → Filtration → Chlorination.

It should be disinfection.

How it's option A? Please explain.

Disinfection is the process of eliminating or reducing harmful microorganisms from inanimate objects and surfaces, sterilization is the process of killing all microorganisms.

So, correct answer should be C.