To minimize the risk to the environment and to human health and arising from the transfer of harmful aquatic organisms and pathogens through the discharge of ship's ballast water, an international treaty has been adopted, February 2004. The installation of a ballast water processing system, which complies with the standard of the treaty, is required for ships constructed after 2009. Via various methods; such as electrolytic, ozone and specialized pipes have been developed. However, the practical application has yet to be achieved. Mud precipitating in the ballast tank, and microorganisms in the mud were observed. The processing burden of the ballast water was examined. By developing a test plant to demonstrate of ballast water processing, and using anthracite filtrating, we have obtained basic data of characteristics of marine organism filtration. The unit showed an effective removal of the microorganisms, excepting pathogens, from the natural seawater. This was achieved with low operational costs and avoided impact to environment.
