a) The engineer performing or supervising the discharge operation will, prior to the start of the discharge, confirm the sewage treatment system in operation and verify that the tank and valve arrangements are correct.

b) The discharge of sewage into the sea as per MARPOL Annex IV is as follows:

• (i) Ship is discharging comminuted and disinfected sewage using an approved system at more than 3 nm from nearest land at a moderate rate when the ship is enroute.
                          OR
• (ii) Sewage, which is not comminuted and disinfected, shall be discharged at a distance of more than 12 nm from 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 enroute and proceeding at not less than 4 knots.
                          OR
• (iii) If a ship has in operation an approved Sewage Treatment Plant, the ship can discharge sewage through such fully operational plant and the above restrictions shall not be applicable.
• (iv) When the sewage is mixed with wastes or wastewater having different discharge requirements, the more stringent requirements shall apply.
• (v) In ports, which restrict such discharge as per local regulations, the sewage overboard valve shall be secured and overboard discharge shall be prohibited within port limits. The Master shall confirm such regulations from the local agent and inform the Chief Engineer about it.

The Sewage Treatment System shall be maintained in accordance with ship-specific PMS. Necessary stores, such as disinfectant, are to be checked and supplied once every 6 months in case required.

a) The Master shall notify the Tech Superintendent of any equipment failures that affect the ability of the vessel to properly treat sewage for a period of 48 hours or longer, in accordance with the Procedure for Deficiency Management.

b) The engineer performing, or supervising maintenance of Sewage Treatment System shall enter equipment history and spare parts inventory adjustments into ship-specific PMS.

a) Discharges of sewage within polar waters are prohibited except when performed in accordance with MARPOL Annex IV and the following requirements:

• (i) The ship is discharging comminuted and disinfected sewage in accordance with regulation 11.1.1 of MARPOL Annex IV at more than 3 nautical miles from any ice-shelf or fast ice and shall be as far as practicable from areas of ice concentration exceeding 1/10; or
• (ii) The ship is discharging sewage that is not comminuted or disinfected in accordance with regulation 11.1.1 of MARPOL Annex IV and at a distance of more than 12 nautical miles from any ice-shelf or fast ice and shall be as far as practicable from areas of ice concentration exceeding 1/10; or the ship has in operation an approved sewage treatment plant certified by the Administration to meet the operational requirements in either regulation 9.1.1 or 9.2.1 of MARPOL Annex IV, and discharges sewage in accordance with regulation 11.1.2 of Annex IV and shall be as far as practicable from the nearest land, any ice-shelf, fast ice or areas of ice concentration exceeding 1/10.

b) Discharge of sewage into the sea is prohibited from category A and B ships constructed on or after the date of entry into force.

c) In general, existing Category A and B ships (with the exception of those operating only in less than 1/10th ice coverage, which is considered unlikely, as all Category A and B ships will have a polar ice class) are only allowed to discharge sewage using an approved sewage treatment plant. If no sewage treatment plant is on board, the ship must retain sewage on board until outside polar waters, and then may discharge sewage in line with MARPOL Annex IV requirements.

d) Ships, when operating in polar waters, are subject to stricter discharge limitations for sewage than the existing MARPOL Annex IV requirements.

e) PWOM should also be referred to when in Polar waters and the latest information should be asked from PIC.