PAS system is more efficient option than the baffle where the receptor environment is very sensitive, with no manual requirements as the static Screens. The pump action screen is designed to screen solids greater than 5/6 mm from storm water to prevent the discharge of visible pollutant to our waterways. The screen consists of a screening basket that is automatically cleaned by an air scouring system. Screenings are retained within the continuation flow. OPERATION In dry weather, the waste water goes towards the treatment plant and the system is stopped. During a storm event, the combined water level, rises. If water level reaches the screen level, the combined water flows through of the screen, screening the floating elements. The water without floater elements, go to the receptor environment. At the same time, the water level which reaches the screen, operates a level switch which start the cleaning pump, this pump keeps the grill clean to avoid obstruction in it, thanks to jet-propelling water with air over the screen. LOCATION It is important to have a trap over the pump and the level switch, allowing to extract both systems from the outside.