Sedimentation
Sedimentation is heavy particles settle to the bottom and the clear water moves to filtration. Solid particles entrained by the turbulence of moving water may be removed naturally by sedimentation in the still water of lakes and oceans. Settling Basins are ponds constructed for the purpose of removing entrained solids by sedimentation. Clarifies are settling basins built with mechanical means for continuous removal of solids being deposited by sedimentation.Large particles settle more rapidly than small particles. It would take a very long time for ALL of the particles to settle out and that would mean we would need a VERY large sedimentation basin. So the clarified water, with most of the particles removed, moves on to the filtration step where the finer particles are removed.