The Lektratek crossflow grit extractor mechanism is ideal for the removal of grit from sewage entering the treatment works and has been designed on both the retention and constant velocity principle.
Sewage entering the hopper-bottomed tank is kept at a constant velocity by rag free paddles rotating in the same direction. Prior to removal of sand, silt and grit from the base of the sump it is washed in a counter flow of air and water under pressure from pipes routed to the bottom of the grit hopper. The compressed air supply is also used to form an air lift which elevates the cleaned grit and discharges it through a horizontal pipe into a grit drainage channel, basin or grit classifier for further washing and elevation for disposal.
A pumped grit extraction system is also available whereby a customised submersible pump or self-priming pump(s) are employed in the same design of hopper bottomed tank as for the crossflow option.
The Lektratek shaft mounted screw grit classifier is more than a straight grit conveyor it is a cost effective method for further washing and conveying cleaned grit to a higher level with the minimum of moving parts thus obviating the need for expensive replaceable liners in the trough housing.
Water, grit and organics entering the unit are deflected down into the well and released air is allowed to escape. The motion of the inclined screw conveys grit up the trough and at the same time churning of the grit release trapped organic material. A weir allows organics to return whilst the grit is elevated along the inclined trough out of the water and discharged in a relatively dry condition at the top of the trough.
MATERIALS OF CONSTRUCTION
The full range of inlet works equipment, designed, manufactured and installed by Lektratek Water Technology, can be supplied in a variety of materials to suit all operating and environmental conditions.