Abstract: In an assembly for controlling filtering of vacuum air flow evacuated from a system storage container through an air evacuation duct in vacuum operated waste collection systems, an assembly housing is installed stationary in the air evacuation duct with an inner passage in the assembly housing communicating with the air evacuation duct, a control unit is installed in the assembly housing with a shiftable member intersecting the inner passage in the housing, whereby the shiftable member has one or more air filtering elements and the air filtering element being movable in a direction generally transversal to the inner passage in the assembly housing.