Discharge criteria for MARPOL Annex 4
In this article, we briefly take a look at the Discharge criteria for MARPOL Annex 4 which is as follows:
1) Subject to the exceptions as given in regulation 3 of this Annex, the discharge of sewage into the sea is prohibited, except when:
I) the ship is discharging comminuted and disinfected sewage using a system approved by the Administration at a distance of more than 3 nautical miles from the nearest land, or sewage which is not comminuted or disinfected at a distance of more than 12 nautical miles from the nearest land, provided that, in any case, the 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 of discharge shall be approved by the Administration based upon standards developed by the Organization.
OR
II) the ship has in operation an approved sewage treatment plant which has been certified by the Administration to meet the operational requirements and:
a) the test results of the plant are laid down in the ship’s International Sewage Pollution Prevention Certificate and
b) the effluent shall not produce visible floating solids nor cause discoloration of the surrounding water.
Also read: SOLAS Requirements for Survival Craft Portable GMDSS radio, including 7 Vital ones.
2) The provisions of the above paragraph shall not apply to ships operating in the waters under the jurisdiction of a State and visiting ships from other States while they are in these waters and are discharging sewage in accordance with such less stringent requirements as may be imposed by such State.
3) The discharge criteria for MARPOL Annex 4 also states that when the sewage is mixed with wastes or waste water covered by other Annexes of MARPOL 73/78, the requirements of those Annexes shall be complied with in addition to the requirements of this Annex.
Regulation 3, Exceptions
The above regulation shall not apply to:
1) the discharge of sewage from a ship necessary for the purpose of securing the safety of a ship and those on board or saving life at sea.
OR
2) the discharge of sewage resulting from damage to a ship or its equipment if all reasonable precautions have been taken before and after the occurrence of the damage, for the purpose of preventing or minimizing the discharge.
Ref : MARPOL
The above was just a brief description of the discharge criteria for MARPOL Annex 4. This is more than sufficient for MMD purposes, be it written or the orals.