14 the top plate 14 removably holds the uv subassembly 20 in position and covers the top end of the vertically descending tube 6 a handle 36 is attached to the upper surface of the top plate 14 and is used for inserting and removing the uv subassembly 20 in an embodiment the handle 36 is hollow so as to permit electrical and control wires 72 for a uv illumination source 22 to pass through the handle 36 up the riser pipe 18 and out of the system where it is connected to a suitable power supply the uv illumination source 22 could be uv fluorescent tubes uv leds uv xenon lamps uv mercury xenon lamps uv argon lamps uv deuterium lamps or any other suitable source of uvc radiation in an embodiment the vertically descending tube 6 the influent line 2 and effluent line 10 are formed with standard 4 inch abs pipe and fittings in an embodiment the outer structure of the uv disinfecting device is made primarily of preformed abs plastic pipe although this is not intended as a limitation other suitable materials with sufficient structural rigidity and interconnectability would be acceptable the influent line 2 and the effluent line 10 are connected to the vertically descending tube 6 by use of a double sanitary tee 16 the connections between the double sanitary tee 16 and the influent line 2 and the effluent line 10 are made by inserting the influent line 2 and effluent line 10 into corresponding flanges on the sanitary tee 16 likewise the vertically descending tube 6 is connected to the sanitary tee 16 by inserting the.