A fuzzy expert approach for comparing alternative end uses for requalification of contaminated sites

Abstract

An important aspect in the issue of contaminated sites is their use after remediation. The choice of a certain use has got necessarily socio-economic implications that make it more or less suitable for that site. For this reason it is important to insert socio-economic analysis within the studies on contaminated site remediation and to implement approaches that calibrate extent and modality of the remediation on the basis of potential uses of the site after it. In particular it is important to provide decision-makers with tools that offer them the possibility to consider also this aspect, in order to support their decisions. The specific aim of the socio-economic module is providing the decision makers with a tool that makes possible to compare the different use destinations, outlining possible scenarios linked to alternative uses of the considered site, on the basis of socio-economic considerations (often founded on theories and methods of the spatial analysis) and of local characteristics. Comparing these scenarios it aims at giving indications on which use is more suitable and why. The final objective is just to establish which is the “best” use for that site. The term “best” indicates that it is possible to rank the whole different use destinations. This is a typical multicriteria decision making problem: there is not a natural order in a multidimensional space, so it is necessary to find a device to do it. A method to rank them is to define a function from the attribute space in the real line and so obtain a total order induced by the real number one. The scientific literature is reach of several ways to approach this problem. Here we propose a method typical of Artificial Intelligence: a Fuzzy Expert Systems (FES). The final product is a software prototype for the remediation of contaminated sites: DESYRE (DEcision Support sYstem for the REqualification of contaminated sites, www.r3environmental.co.uk/dstdemo/), that represents a useful tool for decision-makers. Entering data,relative to the considered site, the software is able to elaborate them to give back one numerical index for each possible use destination (UD). These indexes represent synthetic and comparable expressions of the socio-economic implications deriving from each UD. In this way the decision-makers can compare the opportunities coming from the different uses and have a synthetic indicator, without losing the whole information. The software works in a very transparent way, so that it is possible to highlight which factors determine the high or low index value.