The new  International Convention for the Control and Management of Ships’ Ballast Water and Sediments  was completed and adopted in February 2004. When 30 states, representing 35 percent of the world merchant shipping tonnage, have signed the Convention it will enter into force 12 months later. It is difficult to forecast when this will happen. However, requirements for acceptable ballast water management methods and planning have entered into force in several states. Ballast water exchange These are the three methods used to exchange ballast water: Flow through method A process by which replacement ballast water is pumped into a ballast tank or hold intended for the carriage of water ballast allowing water to flow through overflow or other arrangements. At least three times the tank or hold volume shall be pumped through the tank or hold. Sequential method A process by which a ballast tank or hold intended for the carriage of water ballast is first emptied of at least 95% or more of its volume and then refilled with replacement ballast water. Dilution method A process by which replacement ballast water is filled through the top of the ballast tank or hold intended for the carriage of water ballast with simultaneous discharge from the bottom at the same flow rate and maintaining a constant level in the tank or hold. At least three times the tank or hold volume shall be pumped through the tank or hold. The ballast water exchange: has to be done 200nm from nearest land and in water at least 200 metres in depth in cases where the ship is unable to conduct ballast water exchange as above, this should be as far from the nearest land as possible, and in all cases at least 50 nm from the nearest land and in water at least 200 metres in depth when these requirements cannot be met, conduct ballast water exchange in designated ballast water exchange areas. Ballast water treatment The ballast water exchange methods will be phased out as an acceptable method of compl