they wish to save as much oil as possible, the 

 ballast and tank washings may be gradually run to 

 a single tank while the water is withdrawn from 

 the bottom of the tank after settling. The re- 

 covered oil may be discharged ashore at a waste oil 

 terminal or, possibly, retained on the ship and 

 mixed with fresh fuel or the next oil cargo. The 

 clean ballast water may be discharged into the 

 harbor of the loading port. 



The prevention of pollution here depends upon 

 the effectiveness of oil-water separators on board 

 ship. The Maritime Administration sponsored a 

 study of such separators which reached the follow- 

 ing conclusions: 



Present devices used in marine service depend 

 entirely on density difference to obtain oil-water 

 separation. Because in the United States the 

 difference in density of fuel oil and water is often 

 small or non-existent, effluents from these separa- 

 tors do not comply with the terms of the 

 Convention. To date, no satisfactory oil-water 

 separator suitable for marine service has been 

 found which will effectively and reliably separate 

 oil and water having essentially the same specific 

 gravity. 



As a result of this lack of suitable equipment for 

 separating oil or determining the amount of oil in 

 overboard discharge, the ship operator is not in a 

 position to determine whether or not he is 

 violating the Oil Pollution Regulations except by 

 visual observation or catching samples from the 

 discharge line. In the case of a submerged dis- 

 charge, as used in some vessels, observation is 

 limited to sighting the ship's wake, a method 

 limited to detection of large amounts of oil These 

 methods are ineffective in that observed oil con- 

 centrations above the legal limit are already 

 discharged to the sea. Heavy weather complicates 

 the problem of visual observation and at night 

 there is no means of detection. ' ® 



(h) Cleaning Tankers Tanks of tankers must 

 also be cleaned before they enter shipyards for 

 repairs or take on an entirely different grade of oil. 



18, 



Research and Development for a Shipboard Oil and 

 Water Separation System (The Permutit Company, 1963). 



The problems encountered in disposing of the oily 

 water resulting from the cleaning operations are 

 similar to those raised by oily ballast water. 



The petroleum industry itself has made signifi- 

 cant efforts to control oil pollution. Shell Inter- 

 national Marine Limited has proposed a Cleanseas 

 Code which seeks to build a system of control 

 around existing tanker facilities and capabilities. In 

 1964, the American Petroleum Institute adopted 

 a comprehensive set of policies and procedures to 

 prevent oil pollution, which it explained as 

 follows: 



Every effort is being made to retain slop oil on 

 board for subsequent discharge ashore into slop 

 receiving facilities or for comingling with future 

 cargoes when this is acceptable to the cargo owner. 



Oil terminal operators are being encouraged to 

 provide facilities for the reception of slop oil in 

 those cases where the nature of the vessel, its cargo 

 and the trade make such desirable. Methods of 

 minimizing delays incurred as a result of slop 

 disposal are also being adopted by terminals and 

 ship operators. 



Ship repair yard operators are being informed 

 of the problem and encouraged to provide means 

 for disposing of slop oil from those vessels entering 

 the yard for repair. 



Installations which have facilities for reception 

 of slop oil are making these facilities available to 

 any vessel calling to load or discharge cargo. 



In those cases where it is necessary to discharge 

 slop oil at sea, vessel personnel are required by 

 ship-owners to rigidly observe the prohibition 

 zones approved at the 1962 International Oil 

 Pollution Conference. Further, when discharge 

 into permitted areas is necessary, the effluent is 

 put over the side in such a fashion as to promote 

 bacterial oxidation. 



Operators of vessels under charter are generally 

 requested to follow the same pollution abatement 

 practices as used by vessels of the charter. 



Where practicable, vessels are being built with 

 independent water ballast system whereby certain 

 tanks and piping are not used alternately for cargo 

 and ballast 



Very careful attention is paid to the discharge 

 of cargo to assure that every possible gallon of 

 cargo is removed from the vessel That remaining is 

 generally collected in a single tank for future 

 discharge ashore. 



VIII-85 



