In the recent years, packaging made of conventional plastics has been increasingly replaced by materials believed to be more sustainable. However, perceived sustainability must align with scientific assessments, such as life cycle assessments (LCAs). This review analysed 53 peer-reviewed studies published in the time range 2019–2023, aiming at understanding the state of the art in LCA about the environmental impacts of packaging by focusing on the comparison between plastics and alternative materials. The literature showed that consumer perceptions often differ from LCA findings and revealed that, frequently, conventional plastics are not the least environmentally friendly choice. Bioplastics typically show benefits only in the climate change and the fossil resource depletion impact categories. The heavy weight of glass turns out to affect its environmental performances with respect to the light plastics, with reuse being an essential strategy to lower the burdens. The comparison between plastics and metals is more balanced, leaning more towards plastics for food packaging. Similarly, paper resulted often preferable than plastics. Finally, for the other materials (i.e. wood and textiles), the picture is variable. To be competitive with plastics, the alternative materials require improvements like the optimisation of their production processes, their reuse and enhanced end-of-life options. At the same time, recycled polymers could boost the eco-performance of virgin plastics.

This study addresses critical issues in the life cycle assessment (LCA) of phosphorus (P) recovery from sewage sludge ash (SSA). One of the main related challenges is the lack of robust and reliable data inventory. Additionally, the systems for P recovery from SSA are complex and multifunctional, leading to inconsistencies and contradictions in the literature regarding LCA modeling assumptions and results. To tackle these challenges, existing P recovery technologies from SSA are reviewed. A comprehensive analysis of each technology's material and energy flows is conducted based on literature reviews, providing a valuable data source for future LCA-based investigations. Finally, a review of 18 LCA studies on P recovery technologies from SSA is presented, detailing methods for scenario definition, choice of functional unit, handling of multifunctionality, and findings. Different LCA modeling assumptions have been used in the literature to estimate the environmental burden of P recovery from SSA. These include various methods of considering the system function, defining functional unit, and solving multifunctionality. Additionally, studies employ diverse impact categories and assessment methods, leading to differing and incomparable conclusions. So, a set of recommendations is provided to standardize the approaches of LCA studies on P recovery technologies and ensure comparability of results.