A modular support structure comprising multiple chord or arc modules configured to selectively fixedly engage adjacent modules to define a completed annular support structure configured to support a rotary element of a rotary filter. The modular chord or arc segments may fixedly engaged an adjacent chord or arc segment through a fixing mechanism selected from the group consisting of: fasteners, clamps, pins, bolts, locks, locking mechanisms, key and socket mechanisms, spot welding, welding, adhesives, and other fastening mechanisms configured to engage and disengage adjacent chord or arc modules with ease.