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Fortunately the ship was fitted with 8 sewage holding tanks each of 6 tons capacity into
which all soil units discharged and which in turn could be emptied from the ship's bottom. Thus
it was possible to ensure that the sewage holding tanks were chlorinated to the extent of 20 parts
per million before discharge of the contents into the dock water and, as a result of this treatment
no gross nuisance occurred in the Dock.
This instance emphasises the fact that only a minority of merchant ships today are able to
operate an adequate system of sewage treatment while in Port. The majority of ships, ranging
from the most humble cargo vessel to passenger liners of modern design, discharge their crude sewage
directly overside and even in those ships with holding tanks there is normally no attempt at
sewage purification.
The system of sewage disposal in most ships has made little progress since the time when
trough closets were installed and flushed with a hose and it is surely time, from the Public
Health view point for more attention to be paid to this important aspect of ship construction.
The effects of the present practice are easy to assess when thought is given to the subject.
The bigger passenger liners may well have on board some 2,000 persons and the amount of sewage
discharge would be equivalent to that of a small town. In fog the ship may anchor off, or
being under way, pass slowly by, a seaside town with objectionable results to the beaches, or
it may be delayed in an estuary when the discharge would foul the river up stream or down stream
according to the state of the tide. On entering a Dock the sewage discharge from such a ship for
the full 2,000 persons, will certainly be operating for some hours and again on the day of sailing,
and to add to the problem there may well be more than one ship in dock. In cargo ships with a
crew of perhaps 50 or 70 per ship the problem is less onerous and generally there are more cargo
ships than passenger ships.
In London, there is a Port of London Authority Byelaw which requires all w.c.'s on board
ship to be kept locked while the ship is in Dock, and adjacent to each berth there is a block of
public lavatories, some of which are reserved for ship's personnel. It is evident that the object
of these provisions is to prevent the discharge of crude sewage into the non-tidal waters of the
Dock.
Obviously with passengers on a ship it is not practicable to keep w.c.'s locked, and even
with no passengers aboard there are complications. The bigger ships approximate to 700 feet in
length, and with some of the officers and crews living accommodation as f ar as 600 feet from the
gangway and the sanitary accommodation ashore sited a further 200 yards from the gangway, it
makes an aggregate journey of nearly a quarter of a mile. The situation is not appreciably better
in the cargo ships.
Ships officers of all nationalities often complain that shore w.c.'s are not as well kept as
they would expect, especially as wives, when on board ship, are also expected to use these shore
establishments. On this point it may be fairly commented that, in general, shore lavatories are
clean but are, of necessity, of rugged construction designed mainly with a view to being proof
against vandalism. They are inconveniently situated at many berths especially those for women,
and the whole situation is an ever present source of irritation to ship's personnel.
The remedy is simple. There are proprietary designs of sewage purification units available
which are suitable for permanent installation in ships. Such units have been fitted in a few ships
and have already given several years of trouble-free service. The cost of fitting the installation
into new ships during construction is relatively small and it would appear that the time has come
when such installations should be made compulsory in all new ships. In existing ships the cost
is likely to be greater because of the necessity to alter the existing plumbing. Weight and size
are not major problems.
The benefits from a ship-owner's point of view are:—
1. Freedom from minor restrictions.
2. Freedom from fines for contravening Byelaws.
3. No liability to claims for sewage damage to cargo in lighters alongside the ship.
From the view point of ship's personnel there need not be any more "excursions" across the
quay and a very real improvement in comfort and privacy in the Port, particularly in adverse
weather conditions and at inconvenient times.
One word of warning, the term "septic tank" is used very loosly amongst seamen; it should
mean much more than "holding tank" and any proposed sewage purification system, intended for
a ship, should be subject to examination and advice from a qualified sanitarian.
Direct Discharge Ashore
An idea which has been developed recently on a limited scale provides for the untreated
sewage of a ship to be discharged directly into the adjacent shore sewer through a strong flexible
hose connection. It is admitted that this relatively simple solution to the problem has a limited
field of application, yet it has been successfully applied to one cargo ship berth in the Royal
Victoria Dock where such a linkage was made available and the idea is now being studied in
relation to other berths.
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