6.3 CONCLUSION

The water treatment technologies with the most potential to offer solutions to the ballast water problem are:

· ballast exchange;
· filtration;
· heat treatment;
· on-shore treatment facilities;
· continuous deflective separation; and
· U.V. radiation;

A summary of the treatment options discussed is provided by Table 7. The viability of each treatment is indicated and an explanation provided. The shaded areas highlight those treatments which the Committee considers have the most potential to offer solutions to the ballast water problem. The Committee concludes that effective treatment of ballast water is most likely to be achieved by using a combination of existing technologies together with a re-design of ballast water systems presently in operation on commercial vessels.

TABLE 7
Summary of water treatment technologies and their application in the treatment of ships' ballast water

Treatment	Application		Viability	Reason
	Ship	Shore
Chemical
Peroxide	X	X	No	Cost/Env. Concerns
Hyper Salination/ Salinity adjustment	X	X	No	Cost/Env. Concerns
Chlorination	X	X	No	Cost/Env. Concerns
Chlorine dioxide	X	X	No	Cost/Env. Concerns
Ozone	X	X	No	Cost
Biocides	X	X	No	Cost
Anti-fouling coatings	X		No	Limited application
Sodium/Calcium Hypochlorite	X	X	No	Cost/Env. Concerns
pH Adjustment	X	X	No	Env. Concerns
Mechanical
Filtration	X	X	Yes	Future potential
Cyclonic Separation	X	X	No	Limited application
Continuous Deflective Separation	X	X	Yes	Future potential
Sedimentation/Flotation		X	No	Limited application
High Pressure Pumping	X	X	No	Limited application
Dedicated Ball. Water Treat. Facility		X	No	Cost
Treatment Ship	X		No	Cost/logistics
Ballast Exchange	X		Yes	Current application
Physical
Electrolytically generated copper and silver ions	X	X	No	Limited application
U.V. radiation	X	X	Yes	Future potential
De-oxygenation	X	X	No	Cost/Env. concerns
Heat Treatment	X	X	Yes	Future potential
Electric Pulse & Pulse Plasma Techniques	X	X	No	Cost/logistics
Acoustic Systems	X	X	No	Limited application
Magnetic Fields	X	X	No	Limited application
Existing Onshore Water Treatment Facilities
Sewage Treatment Facilities		X	No	Logistics
Oily Ballast Water Reception Facility		X	Yes	Possible application
Evaporation Ponds		X	No	Cost/Logistics

* Grey shading shows the Committee's preferred options