Location-allocation combining fuzzy analytical hierarchy process for waste to energy facilities siting in developing urban areas: The case study of Lomé, Togo

Abstract

Waste facilities siting is one of the complex problems encountered by decision makers of waste management in urban developing areas. Waste to Energy (WtE) facilities siting alongside transfer stations involves a Multi-Criteria Decision Analysis (MCDA) and has leveraged waste value chain. However, the process requires to consider the interlinked fields of environment, socio-cultural and economic/technical factors as Geographical Information Systems (GIS) in a context of lack of knowledge and expertise. This study aims to propose a framework of WtE facilities siting through a GIS-based Fuzzy Analytical Hierarchy Process (FAHP) and location-allocation method in Lomé’s case study in Togo. This method was applied with boolean logic and fuzzy overlay operators, to assess the potential sites and optimize their selection through a location-allocation solver considering transfer stations and road networks under ArcGIS. Moreover, WtE technologies were attributed to sites based on the territorial aspect. As result, 30.70% of the study area was excluded and three potential areas with a minimum value of 3.47 km2 comprised between 0.81% and 1.01% of the study area, and have been obtained with an acceptable consistency ratio of 0.09. The potential sites are more influenced by slope and residence criteria under economic/technical and socio-cultural factors, with 29.13% and 19.84% of weight respectively. Therefore, through the location-allocation method two optimized sites are obtained and assigned to transfer stations; the first suitable site close to industrial area is appropriate for the gasifier which consequently classified ahead of the anaerobic digester that is suitable for the second suitable site close to agricultural area. As result, prioritizing WtE technologies and site selection should take into account territory aspect, waste sources as well other environmental, socio-cultural and economic/technical factors. This approach has demonstrated its robustness and serves as a stepwise tool for decision makers in WtE facilities siting in developing urban areas.