From linearity to circularity: analyzing material and energy flows in the Taranto Circolare project

In a world where there is increasing debate about sustainability and the circular economy there is a growing need to measure the progress being made in this direction. The purpose of the thesis is to present the findings of the "Taranto Circolare" project in the measurements of matter and energy flows as well as the degree of circularity in the Taranto province in Italy. Different methods for studying urban metabolisms are presented, with the goal of introducing the most appropriate one for the assessment at the city level, bringing different studies applied to other cities around the world to try to replicate a similar approach to the Taranto area under consideration. The research topic is relevant to the field of sustainability because cities, as centers of aggregation of population, play an important role in the consumption of materials and energy, and it is critical to understand the complex web that governs them in order to act in the direction of circular economy. The thesis will also address the difficulty in gathering data for the study of urban metabolism, presenting in the methodology the numerous approximations made and the observed gaps in order to obtain more accurate results. The findings of the study revealed that the presence of a steel mill and an oil refinery in the province of Taranto has a significant impact on the flow of materials and energy in the area. It also results in a high level of waste management activity when compared to regional levels. Finally, a set of indicators for circularity, material and energy use, waste, and emissions were calculated with the aim of measuring the province's performance over time, with the hope that updates can be repeated at regular intervals to track progress towards a more sustainable territory. Thanks to the evidence provided by the analysis of the results, it was possible to develop a selection of project proposals with the goal of finding alternative uses for waste and materials produced in the area, particularly by-products from the steel mill, waste from mussel farming, sludge produced in the province, and a note also for the area's energy sector. The "Taranto Circolare" project is one of the first examples of material and energy flow assessment at the provincial level in Italy, and it should encourage the development of similar projects in other parts of the country in the near future.