Solids Contact Clarifiers


Solids contact clarifiers combine the process of mixing, flocculation and sedimentation in a single tank. Recirculation of solids and mixing is accomplished by a radial or axial turbine. Flocculation occurs within the reaction well. Sedimentation occurs in the clarification zone. The clarifier is comprised of a mixing zone, flocculation (reaction) zone, sludge blanket zone, and a clarification zone. A turbine draws concentrated settled solids from the bottom, and mixes them with the lower solids concentration influent and disperses it into the reaction well. Solids Contact Clarifiers are typically used in water softening and color and turbidity removal clarifiers in water treatment plants, and polishing or tertiary clarifiers in waste water treatment plants. Solids Contact Clarifiers are particularly advantageous in lime softening of groundwater since the precipitated solids help speed the flow, growing larger crystals of precipitate to provide a thicker waste sludge. Solids Contact Clarifiers have also been applied in the chemical treatment of industrial wastes such as metals removal, and used successfully for cooling tower make up water.