disposed of through dockside sewer connections or pumped overboard in unrestricted waters.
MSDs on Navy ships increase the potential for contamination of berthing and working spaces with raw sewage. Therefore, the Medical Department representative must be familiar with the wastewater disposal system and the procedures necessary to ensure the health and safety of the ships crew.
There are basically three different types of MSDs, including zero discharge systems with full volume flush (FVF), zero discharge systems with reduced volume flush (RVF), and flow-through treatment systems.
The zero discharge system with FVF uses a standard 3 to 5-gallon flush and stores this wastewater in holding tanks until it is discharged. The zero discharge system with RVF also collects and stores the wastewaters until they are discharged. This system differs from the FVF system in that it minimizes the volume of wastewater. The flow-through treatment system treats the water to acceptable limits before it discharges the effluent into the receiving water. Effluent is defined as wastewater or other liquid, treated or untreated, flowing out of a reservoir, basin, sewage treatment plant, industrial treatment plant, or MSD.
The collection, holding, and transfer (CHT) system is the MSD system installed on most naval vessels. It operates in restricted waters where the wastes are collected and stored in holding tanks; at sea the wastes are disposed of over the side; in port all waste is collected in holding tanks and subsequently discharged into a sanitary sewer or ship waste offload barge (SWOB) or held until the ship reaches unrestricted waters and then pumped over the side.
Other, less frequently encountered systems include the Evaporative Toilet System (ETS), the JERED Vacu-Burn Sewage Treatment System, the KOEHLER-DAYTON (KD) Recirculating Flush, and the Pall-Trinity Biological Treatment System. The operation and maintenance of these sewage handling and disposal systems are peculiar to the type of system installed. Such information may be found in the Ships Information Book (SIB) and the Manual of Naval Preventive Medicine, chapter 7.
MSD components (soil and waste drains, discharge lines, plugs, plates, valves, comminutors, motors, pumps, and tank penetrations and manholes) should be regularly inspected for leaks by engineering personnel. The paper towel test can be used to detect leaks from pumps, comminutors, and piping. This test entails opening a paper towel and holding it 2 to 3 inches from the unit for several minutes. Even the finest spray can be detected on the paper towel.
All leaks, spills, or other sources of contamination must be reported to the executive officer, the engineering officer/damage control officer, and the Medical Department representative. The leak must be repaired and the system properly cleaned and, if necessary, disinfected.
Sewage receiving facilities are being constructed at all shore activities with fleet support capabilities. These facilities include sewer risers for the transfer of wastewater from the ship discharge risers to the shore sewer system. Facilities to store, maintain, and repair sewage transfer hoses are also included. Specific information and guidelines concerning all aspects of ship-to-shore wastewater transfer facilities and operations procedures are provided in the Ship-to-Shore Hose Handling Operations Manual, NAVFAC MO-340.
Most Navy ship MSDs are designed to discharge their wastewater to a shore receiving facility when in port. This is normally done by connecting the ship sewage discharge risers directly to the pier sewage discharge risers.
Wastewater may be discharged indirectly through connections to a SWOB or another ship system, which in turn discharges the wastewater into pier sewer risers.
Most sewage connections, including ship-to-shore and ship-to-ship, are made by means of flexible transfer hoses 50 feet in length and 4 inches in diameter. On submarines these hoses measure 2 1/2 inches in diameter. It is the responsibility of the shore based handling crew to deliver sufficient quantities of sewage transfer hoses and to make connections to pier sewage risers. The ships crew is responsible for all ship sewage riser connections.
Sewage transfer hoses must be kept clean and in good repair. After each use they must be