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Black & Grey Water Systems

When processing sewage (black system) be it ashore; residential, public facilities, public transport, in aircraft or afloat no matter what system type or capacity, the monitoring, maintenance and operational tasks remain the same; “unpleasant” but necessary.

With our series of vessels, and to negate some of this unpleasantness, we separate the black system (sewage) and the grey system (galley, shower and hand basin waste) by designing into the hull structure suitably sized individual integral tanks.

The internal design and surface finish of both tanks is given careful attention to ensure that a minimum of maintenance be necessary between scheduled dry dockings. Once dry docked these tanks can be opened, docking plugs removed, cleaned, sanitized and a careful internal inspection carried out. Access to these tanks is provided by large rectangular manholes, permitting easy, comfortable internal inspection. With the tanks being located within the engine room and as this space is completely isolated from the accommodation spaces, any mishaps or offensive odors’ are instantly confined.

Regarding the pumping/handling of both black and grey products, we have, with many years of design/trial experience over a wide range of vessel types, settled on what we consider to be the very best solution. With both these systems we use “Mono™” type pumps as we have established reliability, pumping performance and recognize the high level of corrosion resistance offered. Bearing in mind the above we also select all the necessary sewage/wastewater components to match.


The pumping systems are designed and arranged as simple yet flexible in operation in terms of pumping to “deck discharge” (to shore collection terminal) or when at sea, (well offshore) pumping overboard, whilst maintaining the ability that either pump (2) can pump out either black or grey tank.

The toilets selected follow again, very lengthy research with a “macerator” type chosen. The selection of this type allows flexibility with W.C. location and the W.C. unit is able to pump processed sewerage to the black tank. Grey water is collection is generally achieved by gravity to the grey water tank.

To ensure, whilst in marinas or moored inshore where strict marine pollution criteria exists, we provide level contents gauging with “indication” clearly visible in a prominent position within the wheelhouse to permit vigilant monitoring. As an additional safeguard, overboard discharge valves are lockable, with notices “posted up” advising valve status.

Last Updated (Saturday, 29 August 2020 03:32)