The SWA consists of a concical settling hopper with a stirrer to initiate a rotational movement inside the tank. The rotation facilitates grit settling within the tank while at the same time keeping the organics in suspension. 

The bottom of the hopper is fed with a fluidizing water that washes the organic material out the overflow where it is returned to the wastewater treatment processes. The cleaned grit is transported up the shafted screw conveyor to a grit skip.