Municipal landfill site selection using TOPSIS methodology: A case study for Polatlı, Ankara, Türkiye

Abstract Polatlı, which is the largest and tenth out of twenty fifth most populated county of Ankara is well known for being one of the most productive agricultural districts in Türkiye in terms of its barley and wheat production. However, despite that Polatlı has a relatively dense and rapidly growing population, and bears environmental problems, it does not possess a proper municipal solid waste landfill. Since the county currently lacks a proper landfill, the municipal waste is deposited in an improper open dump site that is located to the south of the county. Concerns have been raised due to fire incidents reported and due to scattering of the waste material throughout the neighborhood of the open dump site and to the other parts of the city due to the lack of fencing at the open dump site. Another environmental problem is caused by biogas energy producing companies in the district that dump their processed animal wastes in the farm fields which endangers public health. In addition, extensive illegal waste dumping in the neighborhood of the open dump site exists. The objective of this study is to select the best alternative municipal landfill site location for the Polatlı County, Ankara. To fullfil the disposal needs of the county, landfill site selection has been performed in this study by considering criteria including, air traffic safety, geology, land use, distance to settlement, distance to roads, drainage, slope, erosion, distance to fault and distance to earthquake epicenters. These criteria have been ranked and evaluated in a GIS environment prior to selecting the best alternative landfill site through “The Technique for Order Preference by Similarity to Ideal Solution (TOPSIS)” method of Multi-Criteria Decision Analysis (MCDA). The results of the landfill site selection methodology indicated that amongst the three alternative landfill sites, the best locations to construct a landfill were chosen to be those two alternative sites that were situated north northeast (NNE) and north northwest (NNW) of Polatlı, respectively.