Which statement best describes filtration in water treatment?

Which statement best describes filtration in water treatment?

• A. It removes dissolved minerals and is the final step before disinfection
• B. It is the final step in removing matter and organisms, and is typically followed by disinfection
• C. It adds chlorine during filtration
• D. It is used only for taste improvement and has no effect on pathogens

Answer: (B)

Filtration is the step that physically removes the remaining suspended particles and many microorganisms after the initial treatment steps, preparing water for disinfection. This stage often uses beds of sand, other media, or membranes to capture fine particles that passed through earlier processes. Because of that, the statement that filtration is the final step in removing matter and organisms and is typically followed by disinfection is the best description. After filtration, disinfection is applied to inactivate any remaining pathogens, providing a final barrier of safety. Filtration does not remove dissolved minerals, which explains why the option claiming it removes dissolved minerals is not accurate. Chlorine or other disinfectants are added after filtration, not during filtration, so the idea of adding chlorine during filtration isn’t correct. And while filtration improves taste and clarity, it does more than taste—it's about removing particulates and many microbes, not just improving flavor.

Filtration is the step that physically removes the remaining suspended particles and many microorganisms after the initial treatment steps, preparing water for disinfection. This stage often uses beds of sand, other media, or membranes to capture fine particles that passed through earlier processes. Because of that, the statement that filtration is the final step in removing matter and organisms and is typically followed by disinfection is the best description. After filtration, disinfection is applied to inactivate any remaining pathogens, providing a final barrier of safety.

Filtration does not remove dissolved minerals, which explains why the option claiming it removes dissolved minerals is not accurate. Chlorine or other disinfectants are added after filtration, not during filtration, so the idea of adding chlorine during filtration isn’t correct. And while filtration improves taste and clarity, it does more than taste—it's about removing particulates and many microbes, not just improving flavor.