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Germany, Austria, Switzerland


Circular Grit Washer

More environmentally conscious disposal and significant reduction of costs by lowering the amount of organic matter in the washed grit.

Aqseptence Group offers you the largest range of grit washing systems worldwide and the most comprehensive variety of constructional and process technological designs. As such we are able to optimally tailor a grit treatment process to meet your specific requirements.

The Noggerath® Grit Washer GWC provides washed wastewater grit with less than 3% organic material. This reduction in the amount of residue means considerable savings on transport costs can be achieved. In addition, the reintroduction of the washed organic matter into the wastewater stream leads to an increase in nutrient availability. This means that the addition of external carbon might not be necessary for downstream denitrification processes and may also result in an overall improvement in gas production in any sludge digestion.


Unique Features

  • Robust, thick-flight spirals
  • Spirals and agitator have bearings at drive end only, no submerged bearings
  • No separate outlet for organic matter required
  • No compressed air required
  • Coarse solid handling up to 35 mm dia
  • Less fine grit discharge and lower wash water consumption
  • Less turbulence in the washing zone and, therefore, a low ascending speed


The grit/liquid mixture is fed tangentially into the circular grit chamber and after an orbit of approximately 300° flows into the outlet of the washing tank via an overflow weir. In the course of this circular movement, the grit sinks to the bottom of the washing tank by gravity. 

The circulating movement of the agitator mounted in the washing tank causes a separation of the grit into light and heavy components. The agitator fingers mounted in the lower area of the washing tank cause the grit particles to rub against each other and remove sticky organic residues through abrasion. The organic residues are washed out in an up-current flow process. The washed grit accumulates at the bottom of the washing tank and thus creates an increase in the torque to be applied by the agitator motor.  The grit is removed by the discharge conveyor when a certain density of grit has been reached – this level is set as resisting torque on the motor load monitor and the removal is carried out at pre-determined intervals.

Cambrils STP, Spain - Optimal Sewer Grit Treatment in a standardized System