Spatial and multi-criteria decision analysis-based methodology for landfill site selection in growing urban regions.

The construction of landfills is not an alternative option, since a landfill is always a necessary component of the specific waste management system that will be developed. One of the serious and growing potential problems in large urban areas is the shortage of land for waste disposal. In solid waste management programmes, use of geographic information systems (GIS) is a very significant tool because the selection of a suitable site is a very time-consuming process. The analytic hierarchy process in GIS provides objective mathematics to process the subjective preferences of individuals or groups and arrive at a decision. The present paper describes a spatial methodology which comprised several methods, such as multi-criteria analysis, that originate in different scientific fields. The final goal of the methodology was to evaluate the suitability of the studied area (Trabzon, NE Turkey) in order to optimally select a landfill site. Different constraint maps were overlaid with spatial analysis modules to obtain a final suitability map for Trabzon City and five suitable areas were identified. An analytic hierarchy process was applied to select the most suitable solid waste disposal site for municipal waste in the city among these alternative candidate sites. The Düzyurt area was found to be the most suitable solid waste disposal site. However, geotechnical investigations indicated that some remedial measures would be needed before this landfill site could be used.