Abstract
The problem of water scarcity has been observed across the globe. Water reuse opens opportunities for natural water quality improvement and an improved management of competing water demands. In recent years, membrane assisted technologies have demonstrated success in various water reuse scenarios. Considering scientific and practical issues in futuristic scenarios (particularly the ones considering potable reuse), the coextensive requirement on technological adaptation would necessitate the development of decision making frameworks. Therefore, the aim of this study is to carry out a critical evaluation of different membrane assisted wastewater treatment technologies by applying and developing decision support approaches. To achieve this aim, appraisal of the representative water reuse technologies and water reuse criteria was carried out. The following decision support approaches have been analysed and developed in this study: 1. Weighted Multi-criteria Analysis and Technology Assessment-Analytic Hierarchy Process (AHP). 2. Integrated Analytic Hierarchy Process-Preference Ranking Organisation Method for Enrichment Evaluations (AHP-PROMETHEE). 3. Group decision-making approach 1: Multi Criteria Multi Expert Decision Making (MCMEDM) Method- Fuzzy Logic Based: Technique for Order Preference on Similarity to Ideal Solution (TOPSIS). 4. Group decision-making approach 2: Improved Multi Criteria Multi Expert Decision Making Method - Fuzzy Logic Based: TOPSIS-AHP. The first approach (weighted multi-criteria analysis) formed the basis of developing a more advanced approach (integrated AHP-PROMETHEE) that allows ranking of candidate technologies in wastewater reuse while considering more number of technologies and criteria. Based on strength and weaknesses of these two approaches, two group decision-making (GDM) approaches were developed to fulfill the main aim of the study. The results show that in scenarios considering potable water reuse applications, the presence of nanofiltration or reverse osmosis is important for achieving higher level of effluent quality through membrane processes. Water quality and community acceptance were considered to be the most important criteria in these scenarios. The results from the analysis of scenarios associated with non-potable water reuse showed that a lower level of treatment is usually expected, since cost-related criteria and energy consumption were more important. The developed methods showed the advantage of using fuzzy set theory to interpret linguistic variables during decision making. The systematic analysis using these methods has resulted in the development of a framework for the appraisal of various water reuse scenarios, and the inferences coincide in general with recognised case studies of water reuse.