Sufficient countries have now ratified MARPOL Annex IV – ‘Prevention of Pollution by Sewage from Ships’, to bring the Annex into force. The new Annex, which will enter into force on 29th September 2003, will apply to ships of 400gt and over engaged on international voyages, and ships of less than 400gt that are certified to carry more than 15 persons. It will apply to ships with the building contract placed or the keel laid on or after 29th September 2003, the delivery of which is three years or more after 29th September 2003. Ships delivered prior to 29th September 2003 are to comply by 28th September 2008.

The Annex requires ships to be provided with a standard discharge connection and a holding tank, an approved sewage treatment plant or an approved sewage comminuting and disinfecting system. The discharge of sewage will be prohibited less than 12 miles from land unless via a comminuting and disinfecting system. At more than 12 miles from land the discharge of sewage will be prohibited from holding tanks unless the ship is on route proceeding at more than four knots or the discharge is from a sewage treatment plant.

On completion of an initial survey an International Sewage Pollution Prevention Certificate can be issued. The certificate is valid for five years; annual and intermediate surveys are not required. An additional survey is only required to be held if the equipment is changed, repaired or following an accident or defect which substantially affects the efficiency or completeness of the equipment. Existing ships holding a valid Certificate of Compliance with MARPOL Annex IV, may be issued with an International Sewage Pollution Prevention Certificate on completion of a general examination which will be valid until the expiry date of the existing Certificate of Compliance.