Sludge (Oily Waste)
Sludge is the oily residue and waste that accumulates from a ship's machinery operations — from purifying fuel and lube oil, draining tanks, and separating oil from bilge and engine-room water. It is a semi-solid oily waste that must be collected, stored and disposed of properly, not discharged overboard.
Handling sludge is governed by MARPOL Annex I: ships must store it in dedicated tanks, log every transfer and disposal in the Oil Record Book, and either incinerate it on board or land it ashore to approved reception facilities. Because falsifying oil-record entries or illegally discharging sludge attracts severe penalties (the classic “magic pipe” offence), sludge management is a serious compliance matter — accurate records, proper equipment (oily-water separators, incinerators) and correct disposal are all part of a well-run engine room and a clean PSC and vetting record.
Sludge is where environmental compliance gets real: illegal discharge and false Oil Record Book entries are among the most heavily prosecuted offences at sea, with ships detained and officers jailed. Proper sludge collection, logging and disposal — and the equipment behind it — protect the operator from ruinous penalties and reputational damage. It is compliance that ship managers cannot afford to get wrong.
How must ship sludge be disposed of?
Stored in dedicated tanks and either incinerated on board or landed ashore to approved reception facilities, with every transfer logged in the Oil Record Book — never discharged overboard.
What is a "magic pipe"?
An illegal arrangement to bypass pollution-prevention equipment and discharge oily waste overboard — a serious MARPOL offence carrying heavy penalties.