Prioritization of Sanitary Landfill Criteria Using a Modified Delphi Approach and Development of a Tool for Efficient Site Selection

Selecting a suitable and sustainable site for landfilling is a complex and multidimensional problem that involves various environmental, social, economic, and technical factors. Several approaches exist for selecting an appropriate sanitary landfill, each with its own challenges. This study addresses the need for a systematic and expert-driven prioritization of landfill site selection criteria. In this study, due to its ease, affordability, and primarily its capacity to assess numerous criteria simultaneously, a modified Delphi approach was employed to systematically prioritize the criteria for sanitary landfill site selection. The study followed a three-round Delphi design with 15 experts from relevant fields. Using a 10-point scale, experts rated 31 criteria derived from the literature that influence landfill siting decisions. The criteria spanned various landfill aspects and were categorized into three importance levels based on their weights, which was assigned by the experts using a 5-point scale. According to the results of the Delphi method, the most significant criteria for selecting landfill sites were groundwater quality, proximity to sanitary water source protection zones, hydrogeological features, and geotectonic characteristics, with respective weighted scores of 45.12, 41.76, 39.84, and 37.44 (weight=4.80). The first-level criteria reflect the possible influence of landfill leachate on the quality and quantity of water resources and the welfare and contentment of nearby communities. This study also proposed a tool to calculate the final score of the potential landfill sites based on the weighted scores of the sub-levels of the criteria. The final score serves as a measure of the overall suitability and sustainability of each site, with a higher score indicating greater desirability when comparing various locations.