MEASURING THE CIRCULARITY OF CHEMISTRY-BASED PROCESSES: MESO AND MICRO LEVEL APPLICATIONS

Chemistry is a fundamental piece of the production networks, which nowadays, all over the world, are dealing with the management of their environmental, economic and social impacts. Chemistry is behind many sectors, in a more or less visible guise, such as behind pharmaceutical, food, leather, packaging, automotive, construction and buildings, energy, even recovering and recycling operations. Given these interconnections, this research in the sustainable manufacturing field has focused particularly on the criticalities and possible solutions arising from the chemical-based supply chains. This manuscript, therefore, aims to systematically looking at the chemical industry tensions towards circularity and sustainability. So, three research macro areas have been highlighted: (i) the definition of strategies, concepts, and frameworks for circularity at a general theoretical level; (ii) recovery and recycling processes; and (iii) innovation at the product and process level. Moreover, the cross-cutting theme of the measurement systems for evaluating and monitoring the effects of practices claimed for circularity on the environmental sustainability emerged most strongly. Therefore, by investigating Industrial Symbiosis strategies as a subset of Circular Economy, the issue of measuring circularity has been explored. In particular, the assessment of Industrial Symbiosis in the chemical sector has been addressed by adopting two different perspectives, namely by considering two different scales of implementation: the meso and the micro level. The results achieved through the application of the two different methodologies yield two different types of assessment, each characterised by specific advantages and limitations. The proposed application of assessment tools in this thesis has, however, been focused on the environmental sphere, at the expense of greater aggregation and comprehensiveness, but in favour of greater specificity for a single aspect of sustainability. The proposal of an indicator at the meso level has the advantage of providing an aggregated assessment of the symbiotic nature of a specific production system consisting of multiple industrial entities and multiple exchange flows. While, for the micro level, a Life Cycle Assessment of two alternative scenarios, conventional production and a scenario that contemplates a specific symbiotic flow, has been carried out. So, the LCA methodology has been applied for evaluating a real case study at industrial level, and particularly, the effects in terms of environmental impacts of implementing a symbiotic partnership. The topic of evaluating and monitoring sustainability-oriented practices, with particular reference to chemistry-based processes, is intended to support circular strategies. In general, it has been noted that symbiosis initiatives have developed at different scales, characterised by a certain degree of spontaneity. So, as for the Circular Economy, also the Industrial Symbiosis appears to spread according to a more bottom-up than top-down approach, whose applications have been advanced within companies for coupling environmental and economic goals through the implementation of successful practices. This is, in fact, what has been observed at the micro level in the real case study here presented, focused on a spontaneous exchange flow of secondary industrial raw material, an exchange unit typical of symbiosis strategies