Land suitability for waste disposal in metropolitan areas

Site selection for waste disposal is a complex task that should meet the requirements of communities and stakeholders. In this article, three decision support methods (Boolean logic, index overlay and fuzzy gamma) are used to perform land suitability analysis for landfill siting. The study was carried out in one of the biggest metropolitan regions of Italy, with the objective of locating suitable areas for waste disposal. Physical and socio-economic information criteria for site selection were decided by a multidisciplinary group of experts, according to state-of-the-art guidelines, national legislation and local normative on waste management. The geographic information systems (GIS) based models used in this study are easy to apply but require adequate selection of criteria and weights and a careful evaluation of the results. The methodology is arranged in three steps, reflecting the criteria defined by national legislation on waste management: definition of factors that exclude location of landfills or waste treatment plants; classification of the remaining areas in terms of suitability for landfilling; and evaluation of suitable sites in relation to preferential siting factors (such as the presence of quarries or dismissed plants). The results showed that more than 80% of the provincial territory falls within constraint areas and the remaining territory is suitable for waste disposal for 0.72% or 1.93%, according to the model. The larger and most suitable sites are located in peripheral areas of the metropolitan system. The proposed approach represents a low-cost and expeditious alternative to support the spatial decision-making process.