A GIS and Multi-Criteria Decision Analysis for Landfill Site Selection and Management in Ibadan, Nigeria

M. K.  Oluwanimifise; C. O.  Anyaeche

M. K. Oluwanimifise Department of Industrial and Production Engineering, University of Ibadan, Ibadan, Nigeria
C. O. Anyaeche Department of Industrial and Production Engineering, University of Ibadan, Ibadan, Nigeria

Keywords: Landfill, Sustainability, Solid Waste, South-West Nigeria, Management System

Abstract

Many counties are striving against the incessant wave of urbanization and increasing population to establish a sustainable integrated waste management system. No doubt, the establishment and maintenance of an efficient sanitary landfill is a challenge, especially in developing countries, where many of the required standards and the legal, environmental and socioeconomic factors are frequently unavailable. Ibadan, a city in the south-west of Nigeria, for instance, there is a major problem of insufficient landfill sites, with those available mostly not being quite fit for purpose. Thus, this study investigates the viability and sustainability of the existing dumpsites in the city, using Geographic Information System (GIS) and Multi-criteria Decision Analysis (MCDA)-based Analytical Hierarchy process (AHP) techniques. Waste managers from private firms and the Oyo State Waste Management Agency (OYWMA), as well as citizens across the study area (of Ibadan- North) were interviewed. AHP was used to obtain the weights of factor parameters. Also done was a thematic mapping of the ten selected criteria, viz: closeness to airport, distance from industries, distance from gas pipeline, proximity to road, built-up area distance, slope, land cover and use, distance from highways, distance from rivers, and distance from wetlands. Suitability mapping was prepared by overlay analyses and assigned as ‘very low’, ‘low’, ‘moderate’, ‘high’ and ‘highest’ suitability. The results of the weighted overlay analyses showed that 4.2% of the total space had very low suitability, 5.7% had low suitability, 27.4% was moderately suitable, 45.3% was highly suitable and 17.4% had highest suitability. Given these findings, it is recommended that the existing landfills should be relocated, alongside the creation of five new landfill sites. It is also recommended for government to conduct periodic holistic evaluations of the functionality of landfill sites.