Appropriate Wastewater Treatment Plant Selection Using G-EDAS and G-COPRAS Incorporating G-AHP

Decision theory in the gray environment has found wide application in all areas of knowledge. The goal of gray decision-making is to build an advanced predictive model of a system based on data obtained from multiple sensors or independent experts. Multi-criteria optimization methods, trade-off solutions, gray TOPSIS, multi-branch gray decision-making, distance-from-mean evaluation methods, and comprehensive fitness evaluation methods are among the most important techniques in decision theory in a gray environment. One of the most important considerations when planning and implementing a wastewater treatment plant is selecting the best treatment process. This article first collected data by preparing a questionnaire and interviewing subject-matter experts, and then used the evaluation method based on distance from average (G-EDAS) and comprehensive suitability evaluation method (G-COPRAS) to select the best wastewater treatment system. Based on the three criteria “technical”, "economic,” and “environmental-social” and their sub-criteria, the results indicate that, according to experts, the conventional activated sludge system was selected as the best wastewater treatment system in both processes. In addition, the gray hierarchy technique (G-AHP) was used to determine the most important sub-criteria. Based on this technology, resistance to hydraulic shocks has emerged as the most important sub-criterion.