MARPOL, Annex - II, International Regulations for the Control of Pollution by NLS in Bulk

 Noxious Liquid Substances (NLS) are those which are listed in the International Bulk Code and which fall into category X, Y Or Z. 

Category X : If discharged into the sea from tank cleaning or deballasting operations are deemed to present a major hazard to either marine resources or human health and therefore justify the prohibition of discharge into the marine environment. 

Category Y : If discharged into the sea from tank cleaning or deballasting operations, are deemed to present a hazard to either marine resources or human health and therefore justify a limitation on the quality and quantity of the discharge into the marine environment. 

Category Z : If discharged into the sea from tank cleaning or deballasting operations, are deemed to present a minor hazard to either marine resources or human health and therefore justify less stringent restrictions on the quality and quantity of the discharge into the marine environment. 

Other Substances : OS in the pollution category of Ch. 18 of the IBC Code have been evaluated and found to fall outside category X, Y, Z because they are considered to present no harm to marine resources and human health. 

*THE SPECIAL AREA DESIGNATED FOR ANNEX II IS THE ANTARCTIC AREA, WHERE ANY DISCHARGE OF NLS AND THEIR MIXTURE IS PROHIBITED. *

Discharge Criteria of Category X, Y & Z

After emptying tanks to the maximum extent in accordance with P & A manual, all prewash and Discharge of X, Y & Z substances and mixture must be full compliance of the following :

For X Category :- Tanks are to be prewashed & washing discharged to a shore reception facility until the concentration in the effluent is less than 0.1% by weight. 

For Y and Z Category :- Prewash is to be carried out after Unloading and washing discharged to a shore reception facility until the tank is empty. 

For All X, Y, Z Category :-

Ship must be proceeding en-route. 

Minimum speed 7 kts if self propelled or 4 kts if not self propelled. 

Discharge must be not less than 12 NM from the nearest land. 

Minimum depth should be 25 mtr. 

Discharge must be made below the water line  (Underwater outlets) . 

Procedures and Arrangement (P&A) Manual :-

Every ship certified to carry X, Y, Z substances shall have P&A  manual. 

It's provide to ships officer, the physical arrangements and all the operational procedures with respect to cargo handling, slop handling, and cargo tank ballasting and deballasting. 

 

Manual Provides

1. Main features of MARPOL 73/78 Annex - II

2. General arrangements of ship and cargo tanks. 

3. Cargo pumping, piping & stripping arrangements. 

4. Ballast tanks and ballast pumping and piping arrangements. 

5. Underwater discharge outlet for effluent NLS. 

6. Cargo tank ventilation system. 

7.Tank washing arrangements and wash water heating system. 

8. Cargo unloading procedures & tank stripping. 

9. Information and procedures. 

Cargo Record Book :-

Every ship which is carrying NLS substances and comply with Annex - II shall be provided with cargo record book., 

Entry in cargo record book

• Loading of cargo
• Internal transfer of cargo
• Unloading of cargo
• Prewash according to ships P&A manual
• Cleaning of cargo tank except mandatory prewash
• Discharge into the sea of tank washing. 
• Ballasting of cargo tank. 
• Discharge of ballast water from cargo tank. 
• Accidental or other exceptional discharge. 
• Control by authorize surveyors.