No. 13 - Interpretations of MARPOL Annex IV
The Netherlands Shipping Inspectorate is responsible for the enforcement of the ‘Wet voorkoming verontreiniging door schepen’, the belonging regulations and MARPOL Annex IV. This law refers dynamically to the MARPOL Convention 1973.
Annex IV contains regulations for the prevention of pollution by sewage from ships. The provisions of this Annex shall apply to the following ships engaged in international voyages:
- new ships of 400 gross tonnage and above; and
- new ships of less than 400 gross tonnage which are certified to carry more than 15 persons; and
- existing ships of 400 gross tonnage and above, after September 28th 2008
- existing ships of less than 400 gross tonnage which are certified to carry more than 15 persons, after September 28th 2008.
Abovementioned ships to which the annex applies are in possession of a certificate.
Article 5f of the ‘Regulation prevention of pollution from ships’, implements regulation 4.2 of Annex IV of MARPOL reading; “The Administration shall establish appropriate measures for ships which are not subject to the provisions of paragraph (1) of this regulation in order to ensure that the provisions of this Annex are complied with.”
This regulation concerns ships less than 400GT with a maximum of 15 persons on board. These ships general make short trips and the delivery of sewage in ports is in general possible. These ships may be equipped with a sewage collecting tank or a chemical toilet and don’t need an approved sewage treatment plant or a system of comminuting and disinfecting sewage. Based on article 12a of the Regulation, the Minister of Infrastructure and the Environment (RO is authorized) may issue a declaration of compliance for these ships on request of the shipowner. (Staatscourant 24 September 2008, nr. 185/page 16)
MARPOL Annex IV is not applicable for unmanned pontoons (less or more than 400 GT).
A new ship is a ship built on or after September 27th 2003.
Existing ships the keels of which are laid or which are of a similar stage of construction before October 2nd 1983 shall be equipped, as far as practicable, to discharge sewage in accordance with the requirements of regulation 11 of the Annex.
- Sewage systems
Every ship, which is required to comply with this Annex, shall be equipped with one of the following sewage systems:
- a sewage treatment plant which shall be type approved by the organisation1;
- an approved sewage comminuting and disinfecting system, with sufficient storage capacity;
- a holding tank of sufficient capacity. The holding tank shall have means to indicate visually the amount of its contents;
- in all cases a standard discharge connection conform MARPOL Annex IV, Regulation 10.
- Interpretation of visually indication
The use of a sounding rod is not allowed because of hygienic reasons.
- Interpretation on minimum contents of the holding tank
Volume of sewage in litres per person per day:
| ||Without vacuum plant||With vacuum plant|
| ||Black water||Grey and black water||Black water||Grey and black water|
The content of the sewage tank should be enough for three days as a minimum, unless there are circumstances justifying a smaller capacity.
- Discharge of sewage
The discharge of sewage into the sea is prohibited, except when:
- the ship has in operation an approved sewage treatment plant
- the ship is discharging comminuted and disinfected sewage at a distance of more than 3 nautical miles from the nearest land or sewage which is not comminuted and disinfected at a distance of more than 12 nautical miles from the nearest land
- the ship operates in the waters under the jurisdiction of a state in accordance with such less stringent requirements as may imposed by such state.
Discharge of sewage that has been stored in holding tanks shall not be discharged instantaneously but at a moderate rate when the ship is en route and proceeding at not less than 4 knots. The rate shall be approved by the administration according to IMO resolution MEPC.157(55).
This instruction (in the form of an interpretation) was already in use. In this 3th version there is one amendment.
• The inclusion of the application of the requirements of Annex IV on ships less than 400 GT and not carrying more than 15 persons.
This instruction enters into force from December 1st 2012
Refer to the Recommendation on international effluent standards and guidelines for performance tests for sewage plants adopted by resolution MEPC.2(VI) and after 1 January 2010 MEPC.159(55). For existing ships, national standards are acceptable.