A fluid disinfection module (10) comprises a first housing (12) and a second housing (20) arranged in spaced-apart relationship to each other. The first housing (12) includes tubular support members (28) and (28a) extending laterally therefrom for respective slidable mateable engagement with corresponding tubular support members (30) and (30a) also laterally extending from second housing (20), to vary the lateral distance x between the first and second housings (12) and (20). A locking device maintains tubular support members (28,28a) and (30,30a) in fixed relationship with respect to each other.First housing (12), second housing (20), and corresponding tubular support members (28,28a) and (30,30a) define a framework for supporting one or more ultraviolet radiation sources (18) and (26) that are detachably mounted at one end thereof to housings (12) and (20), respectively. Each of radiation sources (18) and (26) is preferably encased within a quartz sleeve (60), and communicates with one or more ballasts (80) disposed within or without their respective housings (12)(20) for supplying electricity to the radiation sources (18)(26).
