Best-compromise solutions for waste management: Decision support system for policymaking

: Proper management of urban waste might support sustainable and circular development, while mismanagement increases both costs and socio-environmental negative outcomes. In particular, the organic fraction constitutes the largest share of urban waste. In the circular economy framework, it is described as a valuable resource, to be converted into soil improver, biogas and energy. The aim of the paper is to propose a Decision Support System (DSS) for policymakers, based on linear programming techniques. This model is expected to improve the current methodologies for planning and managing organic fraction of municipal solid waste and provide useful insights about public resources allocation. The proposed optimization model is tested on Campania Region (Italy), which is a clear example of the negative implications of improper waste management. Based on the goals recently set by Campania regional government, the model allows to select the most cost-effective and sustainable solutions for treating organic waste. Results show three different scenarios associated to the impacts that each possible outcome has on the stated objectives. The "Ideal Solution" is not achievable, but it is used as a benchmark; the "Max NPV Solution" is feasible, but it reports several major drawbacks. Finally, the "Best Compromise Solution" allows to increase regional composting capability by six time and biogas availability by seven times, with environmental implications that are very similar to the ideal ones.