Sanitary landfill site selection using multi-criteria decision analysis and analytical hierarchy process: A case study in Azuay province, Ecuador

Despite environmental regulations in Ecuador, particularly in the Province of Azuay, the solid waste final disposal management is still a socio-environmental problem, worsened by weak governance processes. The province has three sanitary landfills with almost expired service lives. The site selection was based on circumstantial reasons, which makes landfills more likely to cause environmental pollution and, therefore, have negative implications for public health. The largest landfill serves Cuenca and also leases service to other small cities. The remaining two are small and, accordingly, have limited technology and fewer resources. In this context, the main aim of this study is to evaluate the terrain of the province to find the most suitable area for landfill siting. A multi-criteria decision analysis, integrated with a geographical information system and analytical hierarchy process methodology, was conducted. Fourteen factors and seven constraints were simultaneously analysed, divided into technical, environmental, social, and economic categories; 15 of these criteria were from the Ecuadorian Unified Text of the Secondary Legislation of the Environmental Ministry. According to the results, 76.17% of the territory is not suitable for landfill implementation, and the unrestricted area represents the remaining 23.83%. The highest landfill suitability index (70-81%) is located in the south of the province in Santa Isabel, Ona, and Nabon cantons, which are dry and clay-rich areas.