An attachment and retaining mechanism is described for removably attaching a rotating filter element to a rotating shaft. The rotating filter element includes a filter media that is driven by a drive mechanism that rotates the rotating shaft. The filter element is removably attached to the rotating shaft such that the filter element and filtration system can be periodically replaced and/or serviced. In some arrangements, the drive shaft includes a D-shaped section that interacts with a mating section of the filter element sleeve of the rotating filter element. In other arrangements, the drive shaft includes at least one flat drive surface.