Vortex Type Degritters

Grit Classifying Equipment

Vortex Type Degritters

Grit Classifying Equipment

Grit removed from the influent to a sewage treatment works contains organic matter and solids. The organic solids within the grit are objectionable as they will cause smells and pose health hazards. It is therefore desirable to remove as much organic matter from the grit as possible. The Grit Classifier offers a cost effective solution to further classification and grit washing, whilst elevating the cleaned grit for automatic disposal into a container.

Operation Of The Grit Classifier
The water, grit and organic mixture is introduced into the well over the lower part of the screw where solids settle and are propelled up the inclined trough. A critically positioned weir allows organics to return whilst the grit is elevated along the inclined trough out of the water to be discharged in a relatively dry condition at the top of the trough. Water, grit and organics enter the classifier in a turbulent condition, very often with the presence of air from the grit trap airlift system. A baffle deflects the liquid phase down into the well whilst the air is allowed to escape through a vent pipe. The inclined screw turning within the lower part of the well and underwater gives controlled liquid velocity conditions which keeps the grit solids at the lower part of the trough and at the same time releasing any organic material.

Mechanical Construction
The Grit Classifier is a complete freestanding unit with an Archimedean screw contained within an inclined trough and lower well section. The trough and housing is a specially shaped fabricated container, which houses all of the mechanical equipment. It is completely free standing with flat bases for mounting onto a level concrete floor or plinth. Covers over the unit contain any splashing.