In a conventional treatment train, which step directly follows sedimentation?

In a conventional treatment train, which step directly follows sedimentation?

• A. Filtration.
• B. Disinfection.
• C. Coagulant addition.
• D. Rapid mixing.

Answer: (A)

After sedimentation, filtration is used next. Sedimentation lets most of the heavier floc settle out, but some fine particles remain suspended. Filtration passes the water through media that trap those remaining particles, further removing turbidity and clarifying the water so disinfection can be applied effectively. Rapid mixing and coagulant addition happen earlier to form the floc, and disinfection typically comes after filtration, not directly after sedimentation. So filtration directly follows sedimentation.

After sedimentation, filtration is used next. Sedimentation lets most of the heavier floc settle out, but some fine particles remain suspended. Filtration passes the water through media that trap those remaining particles, further removing turbidity and clarifying the water so disinfection can be applied effectively. Rapid mixing and coagulant addition happen earlier to form the floc, and disinfection typically comes after filtration, not directly after sedimentation. So filtration directly follows sedimentation.