There is described a radiation source module for use in a fluid treatment system. The radiation source module comprises a plurality of elongate radiation source elements secured to a frame element, each elongate radiation source element having a longitudinal axis； a first motive element secured to a first side portion of the frame element； and a second motive element secured to a second side portion of the frame element. The first motive element and the second motive element are configured to reversibly translate the plurality of elongate radiation source elements in a direction substantially parallel to the longitudinal axis. A fluid treatment system comprising the radiation source module is also described.
