Testing of filter technologies for ballast water treatment

Growing concern over the content of discharged ballast water necessitates development of technologies which can decontaminate the water before or during discharge. Many types of filtration technologies exist today which may be applicable candidates for the treatment of ships' ballast water. This treatment applies to the removal of organic and inorganic matter found within the ballast water. To adequately evaluate filtration technologies, appropriate sampling techniques and challenge water parameters must be established. This report details techniques used to examine three different filtration technologies at a pilot scale facility. The technologies tested consist of a screen, disc and media filtration unit. These filters were evaluated for their efficacy in reducing participates and biological organisms from ambient seawater drawn from the Gulf of Mexico. To model expected sediment loads of actual ballast water, challenge water was supplemented with Arizona Test dust to increase the total suspended solids and overall turbidity. Direct enumeration of organisms in the feed water and filtrate was preformed to evaluate filter effectiveness. To examine removability of particulates, particle counting was conducted on the input and output of each filtration system. The performance of each system is presented and the validity of the current testing protocol is discussed.