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U.V. Disinfection

Purpose: The purpose of the UV (ultraviolet radiation) disinfection system is to reduce the number of viable pathogenic organisms in the plant effluent.

Description: The UV disinfection system includes two banks of UV lamp modules arranged in series in a concrete channel. The disinfection channel is located in the northeast comer of the Operations Building following Post Aeration and immediately before discharge. Each bank contains six lamp modules with eight lamps per module. The lamps are arranged horizontally and parallel to the flow through the channel. The modules hang suspended into the channel, supported by stainless steel racks that provide for the addition of up to three additional lamp modules per bank for future expansion. Space is also provided in the channel for installation of a third bank of up to nine lamp modules also for future expansion. The two banks of lamps are also provided with removable stainless steel baffles to reduce the width of the channel as required to maintain the operating depth and velocity necessary for effective disinfection. The baffles will be removed when additional lamp modules are installed to meet future flow requirements. The depth of flow in the disinfection channel is critical to proper operation and performance of the UV disinfection process. The required depth is maintained to within one-inch (±1/2 inch) by an automatic level controller consisting of a counterbalanced vertically mounted swinging gate. The gate in direct response to variations in flow swinging open further as flow increases and closing down as flow decreases to maintain a nearly constant depth in the channel.