To remove suspended solids and chlorine-resistant microorganisms, surface water must be disinfected.

To remove suspended solids and chlorine-resistant microorganisms, surface water must be disinfected.

• A. It is optional
• B. True
• C. False
• D. It depends on the source water

Answer: (C)

The key idea is that removing suspended solids and inactivating microorganisms are two separate steps in surface water treatment. Removing solids is done through processes like coagulation, flocculation, sedimentation, and filtration, which physically remove particles and reduce turbidity. Disinfection, on the other hand, is used to inactivate microorganisms after solids have been reduced. It cannot reliably remove suspended solids. Chlorine-resistant microorganisms are addressed by disinfection, but that doesn’t mean solids are removed by disinfection. In many treatment trains, disinfection occurs after solids have already been reduced to low turbidity to ensure the disinfectant can work effectively. Some organisms are indeed harder to inactivate with chlorine alone, which is why additional barriers (like filtration, UV, or ozone) are used, but this still separates solids removal from disinfection. So the statement is false because destroying or inactivating microorganisms is not the method used to remove suspended solids; those solids must be removed first through physical-chemical treatment steps.

The key idea is that removing suspended solids and inactivating microorganisms are two separate steps in surface water treatment. Removing solids is done through processes like coagulation, flocculation, sedimentation, and filtration, which physically remove particles and reduce turbidity. Disinfection, on the other hand, is used to inactivate microorganisms after solids have been reduced. It cannot reliably remove suspended solids.

Chlorine-resistant microorganisms are addressed by disinfection, but that doesn’t mean solids are removed by disinfection. In many treatment trains, disinfection occurs after solids have already been reduced to low turbidity to ensure the disinfectant can work effectively. Some organisms are indeed harder to inactivate with chlorine alone, which is why additional barriers (like filtration, UV, or ozone) are used, but this still separates solids removal from disinfection.

So the statement is false because destroying or inactivating microorganisms is not the method used to remove suspended solids; those solids must be removed first through physical-chemical treatment steps.