Conversion of clarifier to suction pipe system

In a wastewater treatment system, a suction duct clarifier is converted to a suction pipe clarifier without penetrating existing concrete at the base of the tank. An elevated sludge collection box is added, positioned on the center column to rotate with rake arms, and a series of sludge riser pipes extend from the rake arms up into the sludge collection box for sludge delivery by hydraulic pressure differential. A sludge discharge downpipe is provided within the center/influent column for delivery of sludge from the collection box, and at the bottom of this pipe, above the tank floor, the discharge pipe exits through an opening in the center/influent column. At the outside of this opening is a sludge transfer box that receives sludge exiting the discharge pipe and conveys it down through the existing floor opening and to the existing under-floor RAS return pipe.