Principle of working: Main operational part of rotary screen is a slotted tube which is a welded structure with support profiles which are rods in the axial direction of the tube and surface profiles spirally wound around the support profiles. Water is conveyed by a pump or flows by gravity on the slot tube and passes through the slots (slot sizes 0.25-2.50mm). The solid pollution that exceeds the dimension of the slot, remains on the exterior of the rotating slot tube and it is scrapped and falls down into a container. Treated water, free of solid pollution, flows out from the lower part of the rotary screen. The inlet tank is equipped with an overflown to drain away the excessive wastewater back to the pumping station.