discharge under regulations issued by the Secretary of
In the past, shipboard sewage has been discharged
overboard as a matter of routine design and operation.
Studies have shown that concentrations of sewage in
inland waters, ports, harbors, and coastal waters of the
United States is detrimental to the environment. The
Navy has installed marine sanitation devices (MSDs) on
ships. The MSDs allow ships to comply with the sewage
discharge standards without compromising mission
In 1972, the Chief of Naval Operations (CNO) made
the policy decision to install the sewage collection,
holding, and transfer (CHT) system aboard naval ships.
The CHT system is designed to hold all shipboard
sewage that is generated over a 12-hour period. On large
ships, this goal can usually be achieved. For smaller
ships, the maximum capacity would limit holding time
to 3 hours or less, an insufficient time for the ship to
transit the 3-mile restricted zone.
The Jered sewage treatment plant and the LHA
sewage treatment plant are other types of MSD systems.
The Jered sewage treatment plant is designed for a zero
liquid discharge. It is capable of using the vacuum-burn
principle. Sewage is first collected by a vacuum and then
disposed of by incineration. Sewage can be discharged
overboard when the ship is at sea or pumped to shore
via a connection facility. The LHA sewage treatment
plant is a biological sewage treatment process in which
sewage and activated sludge can be mixed and aerated.
The activated sludge is separated from the treated
sewage by sedimentation and discharged or returned to
the process as needed.
There are distinct hazards to personnel associated
with all sewage systems. These hazards include
explosive gases, toxic vapors, and biological
contaminants. When operating a CHT system, for
example, personnel must be extremely careful so spills
do not occur. ALL SPILLS CAN BE EXTREMELY
HAZARDOUS TO PERSONNEL.
In addition to the removal of CHT contaminants,
CHT spills are sanitized with disinfectants so that
residual bacteria are eliminated. Medical department
personnel must be notified of any CHT black water
spills. Medical department personnel must also
supervise cleanup and sanitation operations in spill
For further information on sanitation systems, refer
to Hull Maintenance Technician 3 & 2, volume I,
NAVEDTRA 10571 (series), chapter 15, and NSTM,
This chapter introduced you to environmental
hazards and control. Remember, pollution takes many
shapes and forms. Pollution attacks the environment and
directly or indirectly affects each of us. Consequently,
we must protect the environment by preventing
On board ship, certain forms of pollution are
sometimes difficult to control, such as heat and noise.
In these cases, the first line of defense is PROTECTION.
In all other cases, we must be concerned with
PREVENTION. Keep in mind that prevention of
pollution, in any form, is everybodys business. Pollute
your environment, and your environment will pollute