The application of the AHP-TOPSIS for evaluating ballast water treatment systems by ship operators

The Ballast Water Management Convention (BWMC) was introduced by the International Maritime Organization (IMO) and it aims at minimizing the transfer of pathogens micro-organisms to the sensitive ecological marine areas, through the ballast of the oceangoing ships. Although it is expected to be enforced worldwide, there are some concerns about the technical requirements of the BWMC and in particular, the application of the Ballast Water Treatment Systems (BWTS) onboard ships. Up to date, there is not sufficient data regarding the performance of existing BWTS making an obstacle to their approval requirement by some states. In this paper, the methodology which is proposed involves expert judgement, utilized for the selection of the BWTS by a ship operator. As an essential part of the research methodology, the TOPSIS and the Analytic Hierarchy Process (AHP) are combined, to determine a cost-benefit decision-making tool, which would be applicable for the ship operators. In this paper, a case study is carried out, showing the potentials of the methodology and evaluating the choice of a BWTS for ships, trading in the USA.