A Novel Fuzzy Framework for Technology Selection of Sustainable Wastewater Treatment Plants based on TODIM Methodology in Developing Urban Areas

Optimum technology selection of wastewater treatments plants (WWTPs) necessitates the adoption of data-driven scientific approaches that satisfy the sustainability requirements of the urban ecosystem. Such approaches should be able to provide actionable insights to decision makers constrained by factors such as increasing population, scarcity of land, and loss of functionality of treatment plants. In this article, we present a criteria system based on the sustainability perspective, which is crucial for the selection of the treatment plant technology from the planning to the operation of the plants. We further suggest a hybrid fuzzy multi-criteria decision making framework (MCDM) under the concept of the alpha cut series which takes into account the risk aversion of decision makers to overcome uncertainties of environmental conditions. To the best of our knowledge, this study is the first to show how a systematic decision-making process is approached by interpreting the interaction of criteria for the selection of treatment plant technology through the membership function of Prospect Theory. The prominent reference criterion manages other sub-criteria according to the function of risk-aversion behavior. The alternatives are ranked by the fuzzy TODIM (an acronym in Portuguese of interactive and multi-criteria decision-making) based on α-cuts sets integrated into the fuzzy analytical hierarchy process (FAHP) including the aggregated weights. We verify usefulness of our approach through a case study conducted with four full-scale WWTPs in a metropolitan city of an EMEA country. The ranking results based on dominance degree of alternatives showed that anaerobic-anoxic-oxic (A2O) without pre-clarification was the most effective process according to sludge disposal cost (C25) calculated as reference criteria. Finally, we present how our framework can be utilized by reflecting the risk perception of decision makers in technology selection of WWTPs for developing urban areas.