Global NEST Journal, Vol 17, No 2, pp 389-396, 2015 Copyright© 2015 Global NEST Printed in Greece. All rights reserved Guler E., Onkal Engin G., Celen M. and Sari Erkan H. (2015), Cost analysis of seawater desalination using an integrated reverse osmosis system on a cruise ship, Global NEST Journal, 17(2), 389-396. COST ANALYSIS OF SEAWATER DESALINATION USING AN INTEGRATED REVERSE OSMOSIS SYSTEM ON A CRUISE SHIP GULER E. 1 1 Gebze Technical University, Department of Environmental Engineering ONKAL ENGIN G. 2,* Gebze, 41400 Kocaeli, Turkey CELEN M. 1 2 Yildiz Technical University, Faculty of Civil Engineering SARI ERKAN H. 2 Department of Environmental Engineering, Esenler, 34220 Istanbul, Turkey Received: 29/12/2014 Accepted: 06/03/2015 *to whom all correspondence should be addressed: Available online: 13/05/2015 e-mail: gengin@yildiz.edu.tr ABSTRACT The best method to treat seawater is known to be the use of reverse osmosis (RO) systems. The cost factor becomes the most important issue when using RO systems. Although quite costly, RO systems are essential systems for ships. As known very well, water is a critical resource on ships, especially the ones serving quite a large number of passengers. In this study, therefore, RO system capability under different conditions together with cost analysis was examined on a relatively small cruise ship. The system used had a daily water treatment capacity of 30 m 3 . The RO system was composed of a sand filter, a cartridge filter, four pieces of membrane filter modules and a mineral filter. During the study, samples from the Black Sea, the Aegean Sea and the Mediterranean Sea, which have different physical and chemical properties, were examined from the quality point of view. A comprehensive cost analysis was also performed in order to determine the feasibility of the system for the production of potable water for a cruise ship. Key Words: Reverse Osmosis, Seawater, Potable Water, Cost Analysis 1. Introduction Reverse Osmosis (RO) is one of the membrane processes, in which seawater is filtered through a high pressure membrane to remove salts and other impurities to produce water suitable for drinking. This system is used on most ocean-going vessels including cruise ships and navy vessels. However, wide-spread implementation of seawater desalination technology is currently limited by complex environmental and economic factors (Greenle et al., 2009; Shaffer et al., 2012). In general, desalination technologies can be classified in two different mechanisms, namely, thermal and membrane-based desalination. Although both technologies find an application area, the RO membrane desalination is the primary choice with a capacity of up to 44% of the total world desalination capacity (Greenle et al., 2009; Misdan et al., 2012). As well known, the major energy requirement for desalination is the seawater pressurization (Khawaji et al., 2008). Pre-treatment is generally needed to eliminate the impurities in seawater, which might increase membrane fouling. The type of pre-treatment to be used largely depends on the feed water characteristics, recovery ratio, and product water quality (Al-Sheikh, 1997; Bou-Hamad et al., 1997; Durham and Walton, 1999; Khawaji et al., 2008). In post-treatment, permeate is generally re-mineralised and/or re-hardened in order to adjust to drinking water standards (Fritzmann et al., 2007; Khawaji et al., 2008).