S.L. 234.47 Art. 5Discharge of Sewage.

(1) The discharge of sewage into the sea is prohibited, except when:

(a) the ship is discharging comminuted and disinfected sewage using a system, in accordance with regulation 4(1), at a distance of more than three nautical miles from the nearest land, or

(b) the ship is discharging sewage which is not comminuted or disinfected at a distance of more than twelve 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, or

(c) the ship has in operation a sewage treatment plant approved by the Administration: Provided that the test results of the plant are laid down in the ship’s International Sewage Pollution Prevention Certificate and, additionally, the effluent shall not produce visible floating solids nor cause discoloration of the surrounding water.

(2) 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 Annex IV.