Flocculation

The coagulation process chemically modifies the colloidal particles so that the stabilizing forces are reduced. To insure that a maximum amount of turbidity is removed, mixing condition and energy input must be properly after rapid mixing, to allow the aggregation of destabilized particles. The coagulated water must be gently stirred to promote the growth of the folc. This process is known as flocculation. Flocculation is an important in precipitation process. The precipitate initially forms into small particles that cannot readily be settled or filtered . In the flocculation process, the mixture is gently stirred to promote the growth of the floc to a size that can be removed by sedimentation and filtration. The typical floc size is in the range from 0.1 to 2.0 mm.The flocculation process relies on turbulence to promote collisions.Velocity gradients are also convenient way of measuring this turbulence. Time is an important factor, and the design parameter for flocculation is Gt, a dimensionless number.