Regulation on Control of Discharge of Residues of NLS

General Requirement:

• This regulation comes under MARPOL Annex II, Chapter 5 - Operational Discharge of Residues of Noxious Liquid Substances, Regulation 13.

• The control of discharge of residues of NLS or ballast water, tank washings or other mixtures containing such substances shall be in compliance with the following requirements.

1. Discharge Provisions:

1.1 The discharge into the sea of residues of substance assigned to Category X, Y or Z or of those provisionally assessed as such or ballast water, tank washings or other mixtures containing such substances shall be prohibited unless such discharges are made in full compliance with the applicable operational requirements contained in this Annex.

1.2 Before any prewash or discharge procedures are carried out in accordance with this regulation, the relevant tank shall be emptied to the maximum extent in accordance with the procedures prescribed in the Manual. 

1.3 The carriage of substances that have not been categorized provisionally assessed or evaluated as referred in this Annex or of ballast water, tank washings or other mixtures containing such residues shall be prohibited along with any consequential discharge of such substances into the sea.

2. Discharge Standards: 

2.1 The Provisions of this regulation allow the  discharge into the sea of residues of substance assigned to Category X, Y or Z or of those provisionally assessed as such or ballast water, tank washings or other mixtures containing such substances the following discharge standards shall apply:

1. The ship is proceeding en route at a speed of at least 7 Knots in the case of self-propelled ships or at least 4 Knots in the case of ships that are not self-propelled.
2. The discharge is made below the waterline through the underwater discharge outlet(s) not exceeding the maximum rate for which the underwater discharge outlet(s) is(are) designed.
3. The discharge is made at a distance of not less than 12 nautical miles from the nearest land in a depth of water of not less than 25 meters.

2.2 For the ships constructed before 1 January 2007 the discharge into the sea of residues of substances in category Z or of those provisionally assessed as such or ballast water, tank washings or other mixtures containing such substances below the waterline is not mandatory.

2.3 The Administration may waive the requirements of the discharge is made at a distance of not less than 12 nautical miles from the nearest land in a depth of water of not less than 25 meters for substances in Category Z, regarding the distance of not less than 12 nautical miles from the nearest land for ships solely engaged in voyages within waters subject to the sovereignty or jurisdiction of the State the flag, of which, the ship is entitled to fly. In addition, the Administration may waive the same requirement regarding the discharge distance of not less than 12 nautical miles from the nearest land for a particular ship entitled to fly the flag of their State, when engaged in voyages within waters subject to the sovereignty or jurisdiction of one adjacent state after the establishment of an agreement, in writing, of a waiver between the two coastal States involved provided that no third party will be affected. 

3. Ventilation of Cargo Residue

• Ventilation procedures approved by the administration may be used to remove cargo residues from a tank.

• Ventilation procedures shall be in accordance with the requirements of this Annex.

• Any water subsequently introduced into the tank shall be regarded as clean and shall not be subject to the discharge requirements in this Annex.

4. Exemption for a Prewash:

On request of the Ship's master an exception fro a prewash may be granted by the Government of the receiving Party, where it is satisfied that:   

1. The unloaded tank is to be reloaded with the same substances or another substance compatible with the previous one that the tank will not be washed or ballasted prior to loading.
2. The unloaded tank is neither washed nor ballasted at sea. The prewash in accordance with the applicable paragraph of this regulation shall be carried out at another port provided that it has been confirmed in writing that a reception facility at that port is available and is adequate for such a purpose.
3. The cargo residues will be removed by a ventilation procedure approved by the administration in accordance with the provision of this Annex.

5. The use of cleaning agents or additives:

5.1 When a washing median other than water, such as mineral or chlorinated solvents, is used instead of water to wash a tank, its discharge shall be governed by the provisions of this Annex. The tank cleaning procedures involving the use of such a medium shall be set out in the Manual and be approved by the Administration. 

5.2 The cleaning additives used for tank washing shall be readily biodegradable and the total concentration shall not be more than 10%. No additives shall contain Category X components.

 

 6. Discharge of residues of Category X:

1. Subject to the provisions of this Regulation, the following provisions shall apply:

1. The tank from which a substance in Category X has been unloaded shall be prewashed before the ship leaves the port of unloading.
• The resulting residues shall be discharged to the reception facility until the concentration of the substances in the effluent to such facility, as indicated by analyses of samples of the effluent taken by the surveyor, is at or below 0.1% by weight.
• When the required concentration level has been achieved, the remaining tank washings shall continue to be discharged to the reception facility until the tank is empty.
• Appropriate entries of these operations shall be made in the Cargo Record Book and endorsed by the Surveyor.
2. Any water subsequently introduced into the tank may be discharged into the sea in accordance with the discharge standards of paragraph 2 of this regulation. 

7. Discharge of residues of Category Y & Z:

1. Subject to the provisions of this Regulation, the following provisions shall apply:
1. With respect to the residue discharge procedures for substances in Category Y or Z, the discharge standards in this Annex shall apply.
2. If the unloading of a substance of Category Y or Z is not carried out in accordance with the manual then: 
1. A prewash shall be carried out before the ship leaves the port of unloading unless alternative measures are taken to the satisfaction of the surveyor offered in this Annex to remove the cargo residues from the ship to the quantities specified in this Annex. 
2. The resulting prewash shall be discharged to the reception facility at the port of unloading or another port with a suitable reception facility provided that it has been confirmed in writing that a reception facility at that port is available and is adequate for such a purpose.
3. For High-Viscosity or Solidifying substances in Category Y, the following shall apply:
1. A prewash procedure shall be applied.
2. The residue/water mixture generated during the prewash shall be discharged to a reception facility until the tank is empty.
3. Any water subsequently introduced into the tank may be discharged into the sea in accordance with the discharge standards of paragraph 2 of this regulation.
4. For substances assigned to category Y that are persistent floaters with a viscosity equal to or greater than 50 mPa.s at 20 degrees celsius and/or with a melting point equal to or greater than 0 degrees celsius the following shall apply in the areas in Paragraph 9:  
1. A Prewash Procedures shall be applied
2. The residue/water mixture generated during the prewash shall be discharged to a reception facility at the port of unloading until the tank is empty.
3. Any water subsequently introduced into the tank may be discharged into the sea in accordance with the discharge standards of paragraph 2 of this regulation.   

2. Operational requirements for ballasting and deballasting
1. After unloading, and if required after a prewash a cargo tank may be ballasted. Procedures for the discharge of such ballast are set out in paragraph 2 of this regulation.   
2. Ballast introduced into a cargo tank which has been washed to such an extent that the ballast contains less than 1 ppm of the substances previously carried, may be discharged into the sea without regard to the discharge rate, ship's speed and discharge outlet location, provided that the ship is not less than 12 miles from the nearest land and in water that is not less than 25 meters deep. The required degree of cleanliness is achieved when a prewash has been carried out.
3. The discharge into the sea of clean or segregated ballast shall not be subject to the requirements of this Annex.

8. Discharges in the Antarctic Area:

1. Antarctic area means the sea area south of latitude 60 degrees S, where any discharges into the sea of Noxious Liquid Substances or mixtures containing such substances is prohibited.

9. Areas to which this Regulation applies or Special Areas:

1. The North-West European Waters
2. The Baltic Sea Area
3. The Western European Waters
4. The Norwegian Sea Area

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Reference: IMO Publications & Documents - International Conventions - MARPOL - Annex II