AnnexV of Marpol , Other similar discharges

Q:-With respect to AnnexV of Marpol explain the significance of following 
Other similar discharges excluded from the purview of operational wastes


Other similar discharges

The definition of "operational wastes" (regulation 1.12 of MARPOL Annex V) excludes grey water, bilge water, or other similar discharges essential to the operation of a ship.  

"Other similar discharges" essential to the operation of a ship include, but are not limited to the following:

•   boiler/economiser blowdown; 
•   boat engine wet exhaust;
•   chain locker effluent;
•   controllable pitch propeller and thruster hydraulic fluid and other oil to sea
•    interfaces (e.g. thruster bearings, stabilisers, rudder bearings, etc.); 
•   distillation/reverse osmosis brine;
•   elevator pit effluent;
•   firemain systems water; 
•   freshwater lay-up;
•   gas turbine washwater;
•   motor gasoline and compensating discharge; 
•   machinery wastewater;
•   pool, spa water and recreational waters; 
•   sonar dome discharge; and
•   welldeck discharges.

While cleaning agents and additives contained in hold washwater, and deck and external  surface washwater are considered "operational wastes" and thus "garbage" under Annex V, these cleaning agents and additives may be discharged into the sea so long as they are not harmful to the marine environment.