BACKGROUND: Ultraviolet disinfection systems used for treating ballast water have several strict requirements such as short exposure time or high disinfection efficacy. Disinfection can be enhanced by a photocatalytic system triggered by ultraviolet light, leading to a reduction in the exposure time necessary and thus a general improvement in the treatment. The use of laboratory disinfection equipment and data modeling enabled determination of the expected treatment optimization. RESULTS: Photocatalysis enhanced ultraviolet treatment, reducing dose requirements by up to 70%, and was particularly effective on the most resistant organism. Treatment optimization was also observed in saltwater conditions. CONCLUSION: Photocatalytic treatment may speed up ballasting and deballasting processes, since a lower ultraviolet dose is required. (C) 2014 Society of Chemical Industry