Advances in seawater desalination technologies
Akili D. Khawajia*, Ibrahim K. Kutubkhanaha, Jong-Mihn Wieb
Royal Commission for Jubail & Yanbu, P.O. Box 30031, Yanbu Al-Sinaiyah, Saudi Arabia Tel. +966-4-321-6100; Fax +966-4-396-0292; email: email@example.com b Saudi Arabian Parsons Limited, P.O. Box 30167, Yanbu Al-Sinaiyah, Saudi Arabia
Received 24December 2006; accepted 3 January 2007
Abstract A number of seawater desalination technologies have been developed during the last several decades to augment the supply of water in arid regions of the world. Due to the constraints of high desalination costs, many countries are unable to afford these technologies as a fresh water resource. However, the steady increasing usage of seawaterdesalination has demonstrated that seawater desalination is a feasible water resource free from the variations in rainfall. A seawater desalination process separates saline seawater into two streams: a fresh water stream containing a low concentration of dissolved salts and a concentrated brine stream. The process requires some form of energy to desalinate, and utilizes several different technologies forseparation. Two of the most commercially important technologies are based on the multi-stage flash (MSF) distillation and reverse osmosis (RO) processes. Although the desalination technologies are mature enough to be a reliable source for fresh water from the sea, a significant amount of research and development (R&D) has been carried out in order to constantly improve the technologies and reduce thecost of desalination. This paper reviews the current status, practices, and advances that have been made in the realm of seawater desalination technologies. Additionally, this paper provides an overview of R&D activities and outlines future prospects for the state-of-the-art seawater desalination technologies. Overall, the present review is made with special emphasis on the MSF and ROdesalination technologies because they are the most successful processes for the commercial production of large quantities of fresh water from seawater. Keywords: Seawater desalination technologies; Multi-stage flash distillation desalination; Multiple-effect distillation desalination; Vapor compression distillation desalination; Reverse osmosis desalination; Freezing desalination; Solar evaporationdesalination; Potabilization; Desalination research and development
*Corresponding author. Presented at the conference on Desalination and the Environment. Sponsored by the European Desalination Society and Center for Research and Technology Hellas (CERTH), Sani Resort, Halkidiki, Greece, April 22–25, 2007.
0011-9164/08/$– See front matter © 2008 Published by Elsevier B.V.doi:10.1016/j.desal.2007.01.067
A.D. Khawaji et al. / Desalination 221 (2008) 47–69
1. Introduction Many countries in the world suffer from a shortage of natural fresh water. Increasing amounts of fresh water will be required in the future as a result of the rise in population rates and enhanced living standards, together with the expansion of industrial and agricultural activities. Available fresh-waterresources from rivers and groundwater are presently limited and are being increasingly depleted at an alarming rate in many places. The oceans represent the earth’s major water reservoir. About 97% of the earth’s water is seawater while another 2% is locked in icecaps and glaciers. Available fresh water accounts for less than 0.5% of the earth’s total water supply . Vast reserves of fresh waterunderlie the earth’s surface, but much of it is too deep to access in an economically efficient manner. Additionally, seawater is unsuitable for human consumption and for industrial and agricultural uses. By removing salt from the virtually unlimited supply of seawater, desalination has emerged as an important source of fresh water. Today, some countries depend on desalination technologies for the...