As the name indicates, the function of the marine oil water separators is to separate the maximum amount of oil particles from the bilge water so that these can be discharged overboard from cargo hold bilges or engine room, oil contaminated spaces or oil tanks. As per regulation, the oil content in the water which is processed from the OWS should be less than 15 parts in every million of oil.
The oily water separator consists mainly of three segments.
- Separator unit. This unit consists of catch plates which are found inside a coarse that separates a compartment and also an oil collecting chamber. In this part, the oil having a density which is lower than that compared to the water, which makes the former rise inside the oil collecting compartment as well as the rest of the non-flowing oil mixture settle down in the fine settling compartment after it passes between the catch plates. After a certain period of time more oil will separate and then collect inside the oil collecting chamber. The oil content of the water which passes through this unit is considered to be around 100 parts per million of oil. A pneumatic or electronic control valve releases the separated oil in the designated OWS sludge tank. The heater can also be incorporated inside this unit for smooth flow as well as separation of water and oil. The first stage will help in the removal of some of the physical impurities in order to achieve fine filtration during the later stage.
- The Filter Unit. This unit is a separate unit whose input comes from the discharge coming from the first unit. This particular unit also consists of three separate stages- filter stage, coalesce stage and the collecting chamber. The particles as well as impurities are separated with the use of a filter and are then settled at the bottom for removal. In the second stage, coalesce induces the coalescence process wherein droplets of oil are being joined to increase the size by breaking the surface tension between the oil droplets inside the mixture.
- Oil Control Unit and Content Monitor. This particular unit functions together in two separate parts- controlling and monitoring. The ppm of oil is being monitored continuously by the OCM or oil content monitor. If there is a high ppm, it will give an alarm and feed data in the control unit. The control unit also continuously monitors the output signal in the OCM.