A collection vessel (20) is connected with inlet fitting assemblies (12, 14) for receiving waste fluids. The collection vessel is connected by a valve (74) with a drain (70) for selectively draining collected fluids. A fluid inlet (84) that is connected with an exterior water source supplies water through interconnecting tubing to rinse waste residue from the collection vessel. The water flows through a housing member (200) that surrounds a tubular member (214) of the inlet assembly. The housing member is spaced by spacers (216) from the bottom surface (220) of a well (210) surrounding the tubular member such that trapped water is drained through a drain outlet (222). Powdered reagent (166, 168) is received in a cup (26) that is carried by a drawer (160) to a position above a fluid mixing reservoir (124). A mechanical actuator (172) lifts a mechanical assembly (174) which defines the reservoir, forcing a cutting blade (180) to pierce and cut open the cup. A pump (128) recirculates the water through the reservoir (124) to make a disinfectant fluid concentrate which is supplied to a venturi (120) to be selectively entrained in the rinse water.