A rotor assembly for use as part of a centrifuge for the separation of particulate matter from a fluid includes a collection chamber housing a particulate separation mechanism and a drive chamber including a Hero turbine which assembles to the collection chamber and which is separable from the collection chamber. The interfit between the drive chamber and the collection chamber imparts any drive chamber rotation due to the Hero turbine directly to the collection chamber for rotation and for particulate separation. By making the drive chamber separable from the collection chamber, the collection chamber can be discarded with its accumulated sludge, allowing the drive chamber to be reused.