How much to discharge?( for tankers and other ships)
Oil discharge from machinery space bilges and oil fuel tanks
It is inscribed in MARPOL that you cannot discharge oil into the sea, not even a single drop. But if you want to discharge oil into the sea, the vessel should be provided with oily water separating and oil filtering equipments. This instrument should separate oil from water and can discharge water with not more than 15 ppm (parts per million) of oil in it. In the event of malfunctioning of the equipment, alarm should sound and the discharge be stopped automatically.
For oil tankers( 400GT and above)
Any kind of oil discharge into the sea is prohibited and if it should be done then there are conditions that should be followed.
For all the oil tankers or ships with 400 GT (gross tonnage) and above, few points should be kept in mind incase discharging of oil is necessary.
During the discharge, it should be noted that the ship is not in any of the special areas. Also the area where the discharge is to be made is more than 50 NM (Nautical miles) away from the nearest land. It is imperative that the ship is proceeding en route.
The rate and quantity of discharge is also to be kept in check. The instantaneous rate of discharge of oil content shouldn’t exceed 30 k per nautical mile. Also of the total quantity oil discharged into the sea, residue formed shouldn’t be more than 1/15000 of the total quantity of the particular cargo, for existing ships and 1/30000 for new ships. An Oil discharge monitor and control system in proper working condition is a must on ship
For ships other than tankers ( 400 GT and above).
For ships that are not tankers, all the rules except a few, are same.
It should be noted that the ship is not within a special area. Also the area where the ship wants the discharge should be more than 2 NM from the nearest land and is proceeding en route. Oil content of the effluent should be less than 100 ppm and the oil discharge monitor and control system should be intact.