Your near-coastal passenger vessel (150 persons) is 2nm offshore. Can you discharge treated sewage overboard? What equipment is required?

A. MARPOL Annex IV — Sewage: applies to new ships of 400 GT+ and ships certified to carry more than 15 persons engaged in international voyages. Discharge rules: (1) UNTREATED SEWAGE: may be discharged at more than 12nm from nearest land when the vessel is en route at not less than 4 knots; (2) COMMINUTED AND DISINFECTED SEWAGE: may be discharged at more than 3nm from nearest land; (3) TREATED SEWAGE: sewage that has been processed through an approved sewage treatment plant (STP) — may be discharged at any distance, provided the STP is type-approved and operating correctly and the effluent does not create visible floating solids or discoloured water. In your scenario: 2nm offshore with 150 persons — untreated sewage cannot be discharged (too close — less than 3nm). Treated sewage from an approved STP may be discharged at 2nm if the STP is operating. REQUIRED EQUIPMENT: MARPOL Annex IV requires either: (a) an approved sewage treatment plant; OR (b) an approved comminuting and disinfecting system; OR (c) a sewage holding tank. Ships in UK coastal waters also comply with UK domestic law (Environmental Permitting Regulations) which may be more restrictive.

B. Sewage can always be discharged at more than 1nm from shore. MARPOL Annex IV has no special requirements for passenger vessels.

C. MARPOL Annex IV only applies in special areas. In UK coastal waters, any vessel may discharge sewage outside the 3nm limit.

D. A 150-person vessel must discharge sewage to shore reception facilities at all times. Overboard discharge of sewage from passenger vessels is never permitted.

A. MARPOL Annex I bilge water discharge — small vessel rules: MARPOL Annex I Regulation 15 covers machinery space bilge water. For vessels of 400 GT and above: bilge water may be discharged overboard only if: (a) outside Special Areas; (b) more than 12nm from the nearest land; (c) vessel is en route (not at anchor or in port); (d) oil content does not exceed 15 ppm (monitored by approved OCM); (e) Oil Record Book entry made. For vessels BETWEEN 400 GT and 400 GT (your vessel at 350 GT): MARPOL Annex I Regulation 15.2 applies a different regime — vessels of less than 400 GT must retain oil residues and bilge water on board or deliver to port reception facilities. There is no 15 ppm discharge provision for vessels under 400 GT outside special areas. PRACTICAL IMPLICATION: your 350 GT vessel CANNOT legally discharge bilge water overboard at 8nm. Options: (a) Pump to the bilge holding tank; (b) Continue to port and discharge to reception facilities; (c) If flooding emergency — it may be necessary, but this is a distress provision only.

B. Any vessel can discharge bilge water beyond 3nm from shore. MARPOL only applies to vessels over 1000 GT.

C. Discharge is permitted at 8nm as long as the bilge water is mixed with sea water to reduce the oil content below 50 ppm.

D. MARPOL does not apply within territorial waters (12nm). Beyond 12nm, all bilge water discharge by any vessel is unrestricted.

A. MARPOL Annex V (as amended 2013) — garbage discharge: (a) FOOD WASTE: may be discharged in territorial sea (>3nm from nearest land) or in special areas (>12nm from nearest land) only when comminuted or ground (passed through 25mm mesh) and the vessel is en route. Outside special areas and >12nm from land: food waste may be discharged without comminution provided it does not create a floating debris hazard; (b) PLASTIC — ALL FORMS: completely prohibited for overboard discharge in all ocean areas. This includes synthetic fishing nets, plastic bags, plastic packaging of any kind. No minimum distance applies — plastic NEVER goes overboard; (c) PAPER, RAGS, GLASS, METAL, CROCKERY: prohibited within 12nm from nearest land; permitted (outside special areas) beyond 12nm from land. IN THIS SCENARIO: food scraps at 15nm — permitted with caution (outside special area, >12nm, en route). Plastic — ABSOLUTELY PROHIBITED at any distance. Paper — permitted at 15nm in non-special areas. A Garbage Management Plan (for vessels 100 GT+) must be carried and followed.

B. Food scraps and paper can always be discharged more than 3nm offshore. Plastics can only be discharged if they are biodegradable.

C. MARPOL Annex V only applies to commercial vessels over 5000 GT. Small near-coastal vessels are exempt from all garbage regulations.

D. All waste can be discharged at more than 12nm offshore — this is the MARPOL Annex V general limit for all waste types.