a vessel which is divided into compartments receives medical and biological fluid wastes through inlet fitting . as the fluid is received , air in the vessel is displaced and is discharged through a vent line , either to atmosphere or to a vacuum source . when a level sensor senses that a level of fluid in the vessel is approaching a preselected maximum , a control circuit closes a valve in the vent line , blocking the discharge of air from the vessel and creating a backpressure that stops the receipt of further fluid . tubing connected to the fittings is disconnected from the patient or other source of fluid and a valve is manually opened to vent the vessel , allowing any residual fluid in the tubing to be drained into the vessel . a drain valve is opened to drain the vessel and the cleaning cycle is commenced . a fittings bell is placed over each inlet fitting such that water with entrained disinfectant from disinfectant reservoir disinfects the inlet nozzles inside and outside . the water with entrained disinfectant is also circulated through a metering reservoir to spray nozzles which spray down the interior surfaces of the vessel . after the nozzle and vessels have been decontaminated , the drain valve is closed and a valve is opened to empty the metered volume of disinfectant solution from the metering chamber into the vessel .