MARITIME – POLLUTION PREVENTION & ENVIRONMENTAL CALCULATOR
Oily Water Separator
A precise tool.
What is the Oily Water Separator & How does it work?
Oily Water Separators (OWS) are critical pieces of equipment on board ships, designed to remove oil droplets from bilge water before discharge. The device must continuously handle the vessel’s waste‑water throughput while keeping the oil concentration below the strict 15 ppm limit set by MARPOL Annex I. The performance of an OWS is typically expressed in terms of its maximum throughput (often in cubic metres per hour) and its oil‑removal efficiency. Operators monitor the measured oil concentration in the effluent; if it exceeds 15 ppm, the discharge is prohibited and corrective action must be taken. Regulatory compliance is verified by sampling the outflow and comparing the measured concentration against the legal limit. Continuous monitoring and periodic testing ensure that the separator remains effective throughout its service life, protecting marine ecosystems from oil pollution.
\eta = \frac{C_{in} – C_{out}}{C_{in}} \times 100\%
\eta = removal efficiency (%)
Parameters
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Frequently Asked Questions
What is the maximum throughput for an Oily Water Separator?
The maximum throughput of an OWS is typically measured in cubic metres per hour and depends on the specific model and capacity.
How does an Oily Water Separator remove oil from bilge water?
An OWS uses physical processes like gravity, centrifugal force, or coalescence to separate oil droplets from bilge water.
What is the oil concentration limit for discharging bilge water?
The strict limit set by MARPOL Annex I is 15 ppm of oil in discharged bilge water.
How often should an Oily Water Separator be maintained?
OWS should be regularly maintained and inspected according to the manufacturer's guidelines and international maritime regulations.
Can an OWS remove all types of oil from bilge water?
While effective, OWS may not remove all types of oil, especially lighter hydrocarbons, which might require additional treatment.
What are the consequences of non-compliance with MARPOL Annex I for ships?
Non-compliance can result in fines, legal penalties, and potential vessel detention or restrictions.
How does an Oily Water Separator impact the environment?
Properly functioning OWS helps prevent oil pollution by ensuring that bilge water discharged at sea meets environmental standards.
Results are for informational purposes only and do not constitute professional advice.