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Royal NavyRoyal Navy

Waste Disposal

Integration
Operation

Plastic Waste
Garbage compactingGarbage compacting It is illegal to discharge plastic waste anywhere at sea. A machine is used to compact and seal all plastic waste. This is then taken to shore in the UK for environmentally sound disposal.

Garbage
Garbage is classified as waste such as paper, cardboard, glass, tins etc. A garbage-processing unit deals with this by taking all kinds of unsorted waste and shredding and compacting it.The compacted waste is then stored on board for later disposal ashore.

Food Waste
Uneaten food is processed through a food pulper, this grinds the waste up into slurry that can be safely discharged at sea when more than 3 miles from land. The Royal Navy is now introducing new generation food pulpers that recycle the water used and produce a "dry" waste that can be stored for later disposal.

Sewage Treatment Plant
Most current warships operate a "Biological Sewage Treatment Plant". In the plant, natural bacterial breakdown of the sewage is assisted by clever recirculation of fluids, resulting in the discharge of a clean, clear and environmentally benign effluent.

Oil and Oily Waste
The discharge of oil at sea is illegal and is regulated by the International Maritime Organisation. All the Royal Navy warships are fitted with oil management systems to ensure against unwanted discharge of oil.

Water and other liquids used in various processes on board RN ships is collected in tanks near the bottom of the ship and is known as "bilge water". Bilge Water cannot be discharged directly into the sea as it may contain oil and other harmful substances, such as detergents.

This "water" is circulated through Wastewater Treatment Machines, which clean it by either using an oil water separator, membrane filtration or both. The resulting cleaned and filtered water is then checked to ensure that it is safe to be discharged.

Membranes act as a filter, allowing molecules or particles of a certain size to pass through, whilst retaining the larger ones. They are typically tubular of flat sheets and are made from polymers or ceramics.

Oil Water Separator Units consist of a vertical settling tank that allows free-floating oil to be skimmed off the surface of the liquid and disposed of or sent for recycling.

The separate module of stainless steel columns, housing tubular ceramic membranes, allows the remaining liquid to be passed through the membranes to remove emulsified oil and other contaminants. This process is known as cross-flow micro-filtration.