Consists of a 60 degrees cone with a short cylindrical top section. It is provided with a stirring shaft, located in its vertical axis, carrying several sets of horizontal arms with rings of nozzles projecting through the sides of the cone for the admission, at several horizons, of the required water currents. At the base of the cone, a classifier column several feet long is fitted, through which refuse discharges continuously to an inclined refuse conveyor. Water is supplied by a centrifugal pump.