Sustainable landfill site selection for hazardous waste using a GIS-based MCDM approach with G-number information

This study aims to present a new integrated framework based on the decision-making techniques and geographic information system (GIS) in order to select the best landfill for hazardous waste. To consider the uncertainty in this process, the G-number theory is used, which includes two components of importance and necessity so as to increase accuracy in choosing the optimal location. In the first stage of this proposed approach, the factors influencing the selection of a suitable site for burying hazardous waste have been identified in three groups, including environmental, social, and economic factors. In the following, the weights of these 13 criteria are calculated using the stepwise weight assessment ratio analysis (SWARA), in order to reduce the ambiguity in attributing weights to the criteria by incorporating the SWARA method and the Importance–Necessity concept (G-number) and to present a novel method, namely the G-SWARA method. By decreasing levels of ambiguity in the final results through the addition of the Necessity and Importance concepts, in the next step, 10 potential locations proposed as the most suitable options by using GIS spatial analysis system have been analyzed and ranked using the weighted aggregated sum product assessment (WASPAS) method based on G-number and site number 6 with 261.97 hectares was ranked first. To evaluate the ranking, the results were compared with F-WASPAS and WASPAS methods, and it was found that the results of the proposed method are more reliable. Sensitivity analysis was also performed to show the degree of ranking stability in different scenarios.