The problem of ballast water with special overview on Croatian regulative

Ballast water is absolutely essential to the safe and efficient operation of modern shipping, providing balance and stability to un-laden ships. Ballast water may also pose a serious ecological, economic and health threat. The introduction of invasive marine species into new environments by ship’ s ballast water has been identified as one of the four greatest threats to the world's oceans. The best way to avoid risk of invasive marine species is exchanging ballast water and replacing it with clean open ocean water - Ballast Water Exchange is the method currently used by all ships that are subject to existing regulations. The biological effectiveness of ballast water exchange has not yet been confirmed and exchange occasionally cannot be performed due to safety concerns. Other options include mechanical treatment methods such as filtration and separation, physical treatment methods such as sterilisation by ozone, ultra-violet light, electric currents and heat treatment, chemical treatment methods such as adding biocides to ballast water to kill organisms and various combinations of the above. Due to non-existence of adequate BWT method new alternative BWT method are exploring.