A rotary disk filter has a central pipe and multiple filter disks arranged around and connected to the central pipe., wherein each filter disk includes multiple filter modules arranged adjacent to one another in the circumferential direction of the central pipe, each having a base frame and two filter elements, which include a filter surface connected to a filter frame. The base frame and the two filter elements delimit a cavity fluidically connected to the central pipe. The filter frames are detachably connected to both sides of the base frame, and removable from the base frame and replaceable with new filter elements. Each filter module is fixed at the central pipe with a threaded spindle independently of the remaining filter modules, wherein the threaded spindle extends through the filter module in the radial direction with respect to the central pipe.