There is described a fluid treatment system. The fluid treatment system comprises:an open channel for receiving a flow of fluid and a fluid treatment zone. The fluidtreatment zone comprising a plurality of elongate radiation source assembliesorientated such that: (i) a longitudinal axis of each radiation source assemblyis transverse to a direction of fluid flow through the fluid treatment zone, and(ii) an end of each radiation source assembly is disposed above a predeterminedmaximum height of fluid flow in the open channel. A first baffle plate is disposedupstream of the fluid treatment zone. The first baffle plate is positioned suchthat a distal end thereof is below the predetermined maximum height of fluid flowin the open channel. In a preferred embodiment, the present fluid treatment systemprovides for an area in which a cleaning system for the radiation source assembliescan be "parked" when not in use. In the so- called "parked"position, the cleaning system may be readily accessed for servicing and the likewithout affecting the flow of fluid through the fluid treatment zone and a fluidtreatment system. This is as significant advantage of the fluid treatment system.
