Under Annex I, the oil content of discharges after treatment must not exceed how many parts per million?

• A. 15 ppm
• B. 5 ppm
• C. 100 ppm
• D. 0 ppm

Answer: (A)

The main idea is that post-treatment bilge water must be kept very clean before it goes back to the sea. Under MARPOL Annex I, the oil content of water after treatment must not exceed fifteen parts per million. This limit is checked after the oily-water separator has treated the bilge water, ensuring the discharge minimizes marine pollution. In practice, ships are allowed to discharge at sea only when the measured oil content is at or below this level and when other conditions (such as distance from land and vessel speed) are met. The other numerical options are not the regulatory standard.