If a turbidity reading remains high after filtration, which issue is most likely?

If a turbidity reading remains high after filtration, which issue is most likely?

• A. Disinfection is inadequate.
• B. Water temperature is too high.
• C. Filtration performance is inadequate.
• D. Color removal is complete.

Answer: (C)

High turbidity after filtration points to a problem with the filtration performance. Filtration is responsible for removing suspended particles that coagulation and flocculation have clustered together. If turbidity remains elevated, the filter isn’t doing its job effectively—issues could be worn-out or fouled media, channeling through the bed, insufficient filtration depth, or inadequate backwashing. Those problems prevent particles from being trapped and removed, so the water still appears turbid after filtration. Disinfection targets microorganisms and does not directly reduce turbidity, so inadequate disinfection wouldn’t explain high turbidity. Water temperature doesn’t create or remove suspended particles in a way that would raise turbidity at the filter stage. Color removal relates to dissolved color, not particulate matter that turbidity measures, so it wouldn’t account for high turbidity after filtration.

High turbidity after filtration points to a problem with the filtration performance. Filtration is responsible for removing suspended particles that coagulation and flocculation have clustered together. If turbidity remains elevated, the filter isn’t doing its job effectively—issues could be worn-out or fouled media, channeling through the bed, insufficient filtration depth, or inadequate backwashing. Those problems prevent particles from being trapped and removed, so the water still appears turbid after filtration.

Disinfection targets microorganisms and does not directly reduce turbidity, so inadequate disinfection wouldn’t explain high turbidity. Water temperature doesn’t create or remove suspended particles in a way that would raise turbidity at the filter stage. Color removal relates to dissolved color, not particulate matter that turbidity measures, so it wouldn’t account for high turbidity after filtration.