The bilge water is an unavoidable by products during operations in ships. From time to time, there are oil leaks running from different machineries like air compressors, diesel generators and main propulsion engine. Sophisticated oily water separators have automatic closures and alarms which are activated when the capacity of oil storage of the equipment has been reached.
The main purpose of the oil water separator system is to separate the contaminants from the oil which can be very harmful to bodies of water. There are regulations regarding safeguarding the ocean from harmful wastes and these regulations are published by the International Maritime Organization through the Marine Environment Protection Committee. Ten years ago, the MEPC issued a new regulation in that every vessel has to follow. The oily water separator should be able to clean bilge water with heavily emulsified as well as other contaminants.
The lowest are on the ship is known as the bilge area. The bilge water that is collected in this part of the ship include drain water from water collecting tanks, boilers, drinking water and other areas where water has the tendency to overflow. Bilge water does not only include water coming from drains. Another system that flows through the bilge comes from the propulsion of the ship. Fuels, hydraulic fluids, solvents, lubricants, antifreeze and cleaning chemicals drain in the bilge area gradually. The oil water separator’s main purpose is to remove the portion of the contaminants before discharging the water to the environment.
Design and operation
Oily water separator equipments are capable of separating oil and water in order to produce clean water. The treated water contains not more than 15 parts/ million oil. The oil water separators are then approved by testing the equipment with specific mixes of oil and water. Initially, the combinations were very simple and gradually complicates. The majority of these equipment models, types and manufacturers start creating gravity separators of bilge water. The oil and water is made to sit in a process called decanting. This does not necessarily have to meet the 15ppm criterion which is why every manufacturer adds additional features to their equipment in order to ensure that this feature is met. The separation of the oil and water that happens inside the machine will allow the oil to float on top and be automatically skimmed off to a holding tank.
Oil record book
All cargo vessels according to the MARPOL convention should keep an oil record book. It is in this book that the chief engineer will record every oil or sludge transfer and water discharges from the vessel. This is important so that authorities will be able to monitor if the crew of the vessel has performed any illegal discharge of oil to the sea.