Summary of Discharge Standards – MARPOL

Oil (Annex I)

Oily waste from cargo tanks of oil tankers

• More than 50 nautical miles from the nearest land; and
• Tanker is proceeding en route; and
• Instantaneous rate of discharge < 30 litres per nautical mile; and
• Total quantity discharge does not exceed 1/15,000 or 1/30,000 of the total cargo (depending on the age of the vessel); and
• Oil discharge monitoring and control system and slop tank arrangement to be operating.

Machinery space bilges for vessels >= 400 gross tons

• Oil and all oily mixtures retain obboard for on shore disposal

or

• Proceeding en route; and
• Oil content less than 15 parts per million; and
• Oil discharge monitoring and control system and oil filtering equipment to be operating;

• Proceeding en route; and
• Has in operation equipment of a design approved by the administration that ensures oil content less than 15 parts per million.

Noxious Liquid Substances (Annex II)

Category X

Tanks to be prewashed before leaving unloading port, residues to be pumped ashore until the concentration of the substance in the effluent is 0.1% by weight or less, as indicated by analysis of samples of the effluent taken by an AMSA marine surveyor. When the required concentration level has been achieved, remaining tank washings to be discharged to the reception facility until the tank is empty. Appropriate entries to be made in the Cargo Record Book and endorsed by the AMSA marine surveyor. Any water subsequently added may be discharged if:

• Ship is proceeding en route at a speed of at least 7 knots; and
• Discharge below the waterline; and
• Ship is > 12 nm from nearest land and depth of water is >25m.

High-viscosity or solidifying Category Y

Prewash in accordance with Convention, residues to be pumped ashore until tank is empty.  Any water subsequently added may be discharged if:

• Ship is proceeding en route at a speed of at least 7 knots; and
• Discharge below the waterline; and
• Ship is > 12 nm from nearest land and depth of water is >25m.

Category Y

Category Z

• Ship is proceeding en route at a speed of at least 7 knots; and
• Concentration of substance in wake of ship < 1 part per million; and
• Amount not to exceed 1m3 or 1/3,000 of tank capacity, whichever is greater; and
• Discharge below the waterline; and
• Ship is > 12 nm from nearest land and depth of water is >25m.

Harmful Packaged Substances (Annex III)

• Jettisoning prohibited.

Sewage (Annex IV)

Comminuted and disinfected sewage using an approved system

• > 3 nm from nearest land.

Untreated sewage stored in holding tank

• > 12 nm from nearest land; and
• discharged at a moderate rate*; and
• ship proceeding en route at a speed of at least 4 knots.

Sewage from an IMO approved sewage treatment plant

• Effluent not to produce visible floating solids nor cause discolouration of the surrounding water.

Garbage (Annex V)

Plastics, including synthetic ropes, synthetic fishing nets, plastic garbage bags and incinerator ashes from plastic products

• Prohibited.

Dunnage, lining and packing materials which will float

• > 25 nm from nearest land.

Food wastes and all other garbage including cargo residues and incinerator ashes (except from plastic products)

• > 12 nm from nearest land.

Garbage that has been ground or comminuted to particles < 25mm

• > 3 nm from nearest land.

• >12 nm from nearest land (Australian Quarantine requirements)

Air Emissions

(Annex VI)

Ozone-depleting substances

• Prohibited

Nitrogen Oxides

• Operation of diesel engines >130kW prohibited unless engine is certified to meet prescribed emission standards.

Sulphur Oxides

• Sulphur content of fuel oil not to exceed 4.5%. **

Incinerators

• Incinerators installed after 1 January 2000 must be certified to meet prescribed emission standards.