The Grit Classifier receives liquids with a large amount of sand and grit from the grit settling device. The liquid enters the classifier through the 4″ pipe to the inlet box in the upper part. The inlet box slows down the flow velocity and releases air and gases through the vent pipe. The sinking sand that accumulates at the bottom of the classifier is led by the screw to the top of the classifier and falls into the evacuation container.