Your examiner asks: "Under Annex IV, when and how can your ship discharge sewage at sea?"

A. Untreated sewage may generally be discharged when the ship is more than 12 nm from the nearest land (at a moderate rate while en route at not less than 4 knots); within 12 nm, sewage may only be discharged if it has passed through an approved sewage treatment plant meeting the effluent standard, or has been comminuted/disinfected and discharged at the permitted minimum distance set for that method (commonly cited around 3 nm for comminuted/disinfected sewage, though candidates should confirm the figure for the equipment fitted). Ships of 400 GT+ (or certified to carry more than 15 persons) must hold an International Sewage Pollution Prevention Certificate.

B. Sewage may be discharged at any distance from land provided it is comminuted, with no minimum distance requirement at all.

C. Annex IV prohibits all sewage discharge anywhere at sea; all sewage must be retained for shore disposal.

D. The 12 nm rule applies only inside Special Areas; outside Special Areas there is no distance restriction on raw sewage discharge.

A. Annex IV does designate Special Areas (e.g. the Baltic Sea) where stricter sewage discharge requirements apply — generally requiring treatment to a defined effluent standard or retention, rather than relying on the general 12 nm/comminution provisions that apply elsewhere.

B. Annex IV has no concept of Special Areas at all; only Annexes I and V recognise them.

C. In a Special Area, sewage discharge rules are relaxed because of the higher population density requiring more frequent disposal.

D. Special Area status under Annex IV applies only to passenger ships, not cargo ships.

A. Annex V categorises garbage into groups including plastics, food wastes, domestic wastes, cooking oil, incinerator ash, operational wastes, animal carcasses, fishing gear, and e-waste — each with its own discharge restrictions; critically, the discharge of plastics into the sea is prohibited everywhere, with no exceptions.

B. Annex V recognises only two categories: hazardous and non-hazardous, with identical discharge rules applied to both.

C. Annex V categorisation applies only to passenger ships; cargo ships are exempt from garbage categorisation.

D. Cooking oil is not covered by Annex V and may be discharged freely as it is considered a food byproduct, not garbage.