Which sequence correctly lists the five basic steps in a conventional surface water treatment process?

Which sequence correctly lists the five basic steps in a conventional surface water treatment process?

• A. Coagulation, Flocculation, Sedimentation, Filtration, Disinfection
• B. Coagulation, Sedimentation, Filtration, Flocculation, Disinfection
• C. Sedimentation, Filtration, Coagulation, Flocculation, Disinfection
• D. Filtration, Disinfection, Coagulation, Flocculation, Sedimentation

Answer: (A)

Understanding the proper order of steps in a conventional surface water treatment process helps show why these actions are arranged to maximize removal of contaminants and protect treated water. Coagulation introduces chemicals that neutralize the charges on tiny particles, allowing them to come together. Flocculation then uses gentle mixing to form larger clumps, called flocs, which are easier to remove. Sedimentation relies on gravity to settle these flocs out of the water, producing clearer liquid. Filtration comes next to trap and remove any remaining particles that didn’t settle. Finally, disinfection adds a sanitizer to inactivate or kill remaining microorganisms before the water is distributed. Other sequences disrupt this flow—filtration before sedimentation can clog filters with unresolved particles, and disinfection before thorough removal steps may be less effective or unnecessary to protect the filters—so the stated order best reflects how conventional surface water treatment is designed to work.

Understanding the proper order of steps in a conventional surface water treatment process helps show why these actions are arranged to maximize removal of contaminants and protect treated water. Coagulation introduces chemicals that neutralize the charges on tiny particles, allowing them to come together. Flocculation then uses gentle mixing to form larger clumps, called flocs, which are easier to remove. Sedimentation relies on gravity to settle these flocs out of the water, producing clearer liquid. Filtration comes next to trap and remove any remaining particles that didn’t settle. Finally, disinfection adds a sanitizer to inactivate or kill remaining microorganisms before the water is distributed. Other sequences disrupt this flow—filtration before sedimentation can clog filters with unresolved particles, and disinfection before thorough removal steps may be less effective or unnecessary to protect the filters—so the stated order best reflects how conventional surface water treatment is designed to work.