From waste to resource: Life Cycle Assessment to optimize innovative recycling processes

The generation of waste is increasing exponentially at the global level, driven primarily by rising consumption. At the same time, natural resources are becoming increasingly scarce and difficult to access. These two converging trends outline a clearly unsustainable pathway in the medium and long term from environmental, economic, and social perspectives. In response, the European Union has promoted the circular economy model, with the aim of preserving the value of materials for as long as possible, extending product lifetimes, and significantly reducing waste generation. However, even circular economy strategies require the use of resources and energy to effectively “close the loop’. To ensure that these processes are sustainable, it is essential to perform comprehensive and rigorous environmental impact assessments. Life Cycle Assessment (LCA) is a well established methodology that enables the quantification of environmental impacts throughout the entire life cycle of a product or process. LCA has traditionally been applied from a “cradle‑to‑grave” perspective. The application of this method to multifunctional systems such as recycling processes poses methodological challenges. At present, there are no unified or consolidated guidelines that systematically support the application of LCA to recycling processes. For this reason, the first objective of the present research is to understand which strategies and methodological choices experts adopt when applying LCA to recycling processes. Based on the findings of the literature review, the second objective is to develop an application model specifically designed for the recycling context. Finally, the third objective is to validate the proposed model through its application to selected case studies representing different types of processes and materials. The project is developed within the extended partnership MICS – Made in Italy Circolare e Sostenibile, funded by the Next Generation EU programme. The methods adopted in this research are: i. a systematic review of the literature conducted according to the PRISMA methodology, ii. the application of the developed model for the implementation of LCA in recycling processes to selected case studies. These case studies cover three distinct recycling or waste management contexts: the recycling of photovoltaic panel, the recycling of textile waste, and the management of post‑consumer wood originating from a furniture manufacturing company. The literature review does not reveal a consistent trend, since practitioners exhibit considerable variability in their modelling practices and methodological choices. Based on the insights derived from the literature, a grave‑to‑cradle model was developed, designed to account for the product system from the end of its first life to the beginning of its second life. The application of this model to the case studies demonstrates that the implemented model is functional and that the use of a consistent modelling structure improves the comparability of results across different recycling contexts. However, the analysis also indicates that the model is not yet fully mature for every type of application, as to ensure its suitability across all types of processes and material streams further refinement is needed. Future developments should focus on optimization of the proposed model to enhance its applicability in a broader range of recycling processes and waste management contexts, particularly at the supply chain level and for additional waste streams such as organic waste and municipal solid waste. Moreover, a unified guideline to support consistent and comparable LCA applications in recycling systems represents a crucial next step. Finally, the research highlights the need of a more comprehensive and dedicated databases, which are essential for improving the robustness and reliability of LCA in circular economy applications.