Regional industrial symbiosis networks for waste minimisation: a case study from Italy

Industrial symbiosis supports a circular economy by fostering resource recovery through inter-industry synergies. Despite growing network scales, regional-level industrial symbiosis networks (ISNs) remain underexplored representing a key research problem. The objective of this study is to develop and demonstrate an innovative methodological framework to investigate the ISN in the highly industrialized province of Brescia. The methodology applies Social Network Analysis (SNA) across three scenarios: the current network (ISNP), a potential network identified through facilitation and research activities (ISNR), and a hypothetical scaled-up network (ISNF) that integrates ISNP with ISNR. By integrating SNA with material flow analyses, novel indicators were developed to evaluate ISNs' impact on regional waste management (WM) performance and the influence of contextual factors. The results reveal that, despite having 459 industrial nodes, the ISNs show low density and high centralisation, dominated by metallurgical companies. The transition to ISNF reveals two key advantages over ISNP: a quantitative increase in recovery of wastes otherwise disposed of (from 1 % to 18 %) and enhanced diversity of waste flows (from 39 to 57 European Waste Codes), aligning with an increased contribution to reducing waste transportation and disposal (from 14 % to 51 %). Barriers to scaling the ISN include limited industrial diversity, insufficient partners for waste transformation, and few WM permits, while key drivers involve internal reuse strategies and untapped company participation. In conclusion, the study provides an innovative methodology and case study for analysing ISNs at a regional scale, contributing valuable insights to inform further research and support development of industrial circularity initiatives.