Evaluation of GIS-based multi-criteria decision-making methods for sanitary landfill site selection: the case of Sivas city, Turkey

Landfill is the most common method used to eliminate municipal solid waste in developing countries. As in all developing residential units, Sivas city is also encountering a major solid waste problem menacing both public health and environment. This study analyzes the 7 criteria (geological structure, land ability class, transportation, groundwater, surface water, residential areas, and existing land use) utilized for solid waste landfill area preference reasons by employing some Geographical Information System (GIS) based, multi-criteria decision-making methods such as Analytical Hierarchy Process (AHP) and Simple Additive Weighting (SAW). Evaluation of alternative areas defined by AHP and SAW methods is conducted with the help of Combinative Distance-Based Assessment (CODAS). The study area was classified as most suitable, suitable, averagely suitable, too little suitable and not suitable in terms of their sanitary landfill properties. According to AHP and SAW analyses results, it was determined that a large part of the study area (respectively, 46.82% and 27.81%) is within the category of averagely suitable. After the application based on GIS oriented multi-criteria decision-making analysis, 4 alternative places as solid waste disposal areas were recommended by taking environmental and physical factors into consideration. AHP-CODAS and SAW-CODAS methods were mutually utilized to rank these 4 areas according to their suitability. As a result, Area1 in integrated weights (AHP and SAW)-CODAS was selected as the most appropriate place for sanitary permanent landfill.