Fuzzy sets analysis for ballast water treatment systems: best available control technology

An overview on various ballast water treatment (BWT) technologies aboard different types of ships is presented. These technologies are: (1) Filtration, (2) Cyclonic systems, (3) Heat treatment, (4) Chemical treatment, (5) Ultraviolet radiation, (6) Ultrasound, (7) Electroporation, and (8) Radiolysis. These technologies are proven technologies for BWT in the marine industry. The fuzzy sets methodology is used to perform a comparison among these different Ballast water systems to choose the best available control technology that should be given the highest priority in terms of development and research. The main objective of this paper is to determine the order in which ballast water systems should be given higher priority to be installed to tackle the world wide ballast water pollution problem. These systems are compared according to their benefits and cost. Based on the benefit to cost ratio, the results show that the filtration treatment appears to be the method that will provide the best combination of effective treatment and feasibility. The next two options are the use of ultraviolet and ultrasound. All these three options could be used to produce effective and reliable BWT with minimum cost and optimum benefits in terms of issues related to effectiveness, reliability, global benefits, and safety. The least options are radiolysis and chemical treatment due to their high costs and low safety factors. Also this study tries to clear the way for developing new and existing technology, and to provide a platform for successful treatment solution.