GIS-Based Solid Waste Landfill Site Selection in Addis Ababa, Ethiopia

摘要

Solid waste management is the most difficult task that many countries, both developing and developed, are facing now-a-days. Landfill is one of the easy and cost-effective management systems used in many parts of the world to dispose off solid wastes. However, inappropriate location and mismanagement will result in environmental pollution and public health hazards. The open dumping system that Addis Ababa city has followed for many years is not environmentally sound and socially acceptable because of its inappropriate location. The main objective of this study was to identify an appropriate solid waste disposal site using state-of-the-art technologies to ensure environmental sustainability and public health protection. Criteria such as geology (lithology), groundwater depth, water supply well points, hydraulic conductivity/ soil structure, land-use/ land-cover, slope, drainage pattern (water bodies), roads, airport locations were used for selecting a suitable landfill within the study area. GIS-based Multi-Criteria Evaluation methodology was employed to perform the spatial decision making process. Analytical Hierarchy Process of pair-wise comparison module was adopted to derive external and internal values of weight for all the criteria and classes within each criterion, respectively. Weighted Linear Combination was used to integrate the criteria maps and produce an overall landfill suitability map. Accordingly, 40.5 km2 (7.7%), 68.7 km2 (13%), 0.7km2 (0.01%) and 417.8 km2 (79.3%) of the total study area was found to be highly, moderately, marginally and un- suitable for landfill, in that order. Among the highly suitable landfill areas, 12 candidate sites were selected and evaluated in terms of size of the site, distance from the city center and the nearby settlements to choose the most suitable site. Three suitable solid waste disposal sites with the least negative effects on environment as well as public health have been identified with first, second and third order suitability ranks.