In recent years, a large number of developed countries have considered water reuse schemes as a mandated alternative water resource to tackle water scarcity. With increasing knowledge on and understanding of the merits of water reuse in developing communities, a number of planned water reuse schemes have also been established (Chen et al., 2012; Fatta-Kassinos et al., 2011a). The range of water reuse issues and aspects is overwhelming; for example, selecting treatment processes, sequencing of selected technologies in parallel or in series in a treatment train, and monitoring and control of treatment plants (Evenson and Baetz, 1994).
There are numerous processes and technologies which can be implemented for water reuse applications. Currently, a large number of water reuse projects and pilot studies are under operation, with many more in planning and construction phases (chen et al., 2012). With this trend of development and considering the fact that sustainability is highly required, technology selection and decision support methods seem to be essential (Hamouda et al., 2009; Garrido-Baserba et al., 2012).