Selection of Desalination System for Commercial Vessels by Implementing Improved Intuitionistic Fuzzy TOPSIS Method

Table 3

The alternatives and their definitions.

Alternative	Description
Freshwater generator (A1)	The freshwater generator is a desalination system that is permanently used on ships that do not make short voyages and do not supply freshwater from the port. This system is also known as the evaporator. This system, which boils seawater and distills it with high energy consumption, is used conventionally on ships.
Reverse osmosis method (A2)	This method, which can provide compression with high pressure by means of a pump, filters the freshwater and removes all other beneficial and harmful components, especially sodium chloride, from seawater. Over time, the development of nanotechnology in membrane filters and the production of freshwater at high flow have made the reverse osmosis method attractive.
Installation of a membrane filter in addition to existing mechanical + UV ballast water treatment systems (A3)	It is a very complex system, which was started to be used on ships in 2017. It contains UV radiation and hydrocyclones that kill harmful microorganisms that can be transported through ballast waters, especially filtration.; The question of removing the use of the conventional freshwater generator by installing an additional membrane filter on this mechanical system has been raised.