An oily water separator clears the bilge water of oily content to bring it inside the acceptable range to discharge it overboard. An oily water separator is a machinery for such importance that it is handled by only the 2nd or chief engineer. (However, the duty engineer might also be asked to operate under supervision)
Operating an Oily Water Separator
An oily water separator can only be operated when the ship is sailing and en route. According to MARPOL, the oil content of the effluent must be less than 15 ppm and the ship has in operation an oil discharge monitoring and control system and oily-water separating/filtering equipment.
In case of failure to follow any of the above mentioned rules, the ship will be fined and stopped, and the chief or 2nd engineer can even be imprisoned.
Because of such high risks, operating an oily water separator should be done with utmost precision to minimize the risks of marine pollution. Though a “How to Operate?” guide is always posted near the oily water separator, there are few points to be kept in mind and followed to prevent any mistake.
The following points are to be followed while operating OWS.
1) OWS overboard manual discharge valve is to be kept locked and keys are to be kept with the chief engineer. Open the lock and overboard valve. Open all the other valves of the system.
2) Open the desired bilge tank valve from which the oily water mixture is to be discharged from OWS.
3) Open air if the control valves are air operated.
4) Switch on the power supply of the control panel and OCM unit.
5) Fill the separator and filter unit with fresh or sea water to clean up and prime the system till the water comes out from vent of second stage.
6) Start the OWS supply pump which is a laminar flow pump and one that will supply the oily water mixture to OWS.
7) Observe the OCM for ppm value and keep checking sounding of bilge tank from where OWS is taking suction and of the OWS sludge tank.
8 ) A skin valve/sample valve is provided just before overboard valve and after the 3-way valve. Keep a check on the sample for any effluent and clarity.
9) Keep a watch on the ship side at the overboard discharge valve.
10) After the operation, Switch off the power and shut and lock the overboard valve. Keys to be handed over to the chief engineer.
11) Entry to be made by chief engineer in the Oil Record Book (ORB) with signature of operating officer, chief engineer and the master.