Engineers are testing a green waste disposal system on Britain’s newest aircraft carrier – reducing rubbish aboard one hundred fold.
During the latest phase of HMS Prince of Wales’ sea trials in the North Sea, sailors are testing her state-of-the-art pyrolysis plants – already fitted to the ship’s older sister HMS Queen Elizabeth – to keep the tonnes of rubbish generated by the 600 sailors and 400 industry engineers and experts on board to a minimum.
During her first two visits to Invergordon, the ship offloaded several tonnes of rubbish – ‘gash’ in Royal Navy parlance – a manual, labour-intensive process given that the 1,000 souls aboard produce upwards of nine tonnes of waste every day, stored in shiny metal drums.
Enter the two pyrolysis plants – which cause material to decompose under extreme temperatures.
Most waste – including food, sewage and waste oils, including those from the galley, but not metals or glass – can be processed by the plants, which can deal with 150kg of rubbish every hour.
The only flame comes from a burner which initially heats the ‘oven’ to 1,100°C – as hot as a large bonfire.
The waste then becomes the fuel; the burner switches off and the plant becomes self-sustaining using minimum fuel.
So 150kg of waste becomes 1½kg – or one and a half standard bags of sugar. At the end of the process you’re left with some grey-blackish ash, known as char, which is stored in drums until the ship puts into harbour again and the gash can be offloaded.
As part of the carrier’s trials, the first of the ship’s two pyrolysis plants was fired up to test seals and the operating temperature.
After that proved successful, the marine engineers are now putting solid waste through the plant before moving on to food, bio sludge (sewage) and sludge oil.
“I’m excited to start working with the pyrolysis plant which is something I have never seen before,” said Marine Engineering Technician Niall Kelleher, one of the carrier’s junior sailors responsible for operating the rubbish machines.
“I am hoping to gain more knowledge on such equipment which will be extremely useful to me over my career in the RN.
“The plants’ waste reduction ratio will benefit the ship’s company with us having far less waste to dispose of during ‘out all gash’ – and enable us to store the waste far easier.”
