Multicriteria decision making applied to waste recycling in Brazil

Waste management, like other environmental issues, tends to be a suitable topic for problem solving using multicriteria decision-making techniques when uncertainty is involved. This paper presents two cases where the decision makers had different preferences. In the first case, social agents required an evaluation of different disposal alternatives for plastic waste. In the second case, existing construction and demolition waste recycling facilities required a performance evaluation. Existing analyses, based on numerical inferences for the alternatives, have not provided conclusive results. The authors' approach used specific case studies and the inclusion of multiple decision makers in the evaluation. With help of THOR, a multicriteria decision support system under development at COPPE/UFRJ and CASNAV, a consistent hierarchy of the possible alternatives was achieved. This paper describes the methodology used to input data and decision-makers' preferences in the decision support system.