Recycling Phosphorus (P) from urban wastewater can secure part of domestic agricultural P supply and contribute to a circular P supply chain. In this paper, we use literature review, stakeholder interviews and analysis, and systems dynamics for the capital cities of Stockholm and Budapest as case studies. We find that political support is a prerequisite for developing the P recycling sector, and policy makers are the most influential stakeholders. P criticality is the main driver for political support. P externalities from mining to sludge disposal should be considered when evaluating P criticality and recycling profitability. We conclude with policy recommendations for the development of the P recycling sector, arguing for legally binding P recycling targets and prioritization of the safest technological solutions available. Our analysis identifies three policy action indicators and five policy interventions in the recycling system.

Bio-waste could play a fundamental role in reaching the EU target to recycle 65% of municipal waste by 2035. The European waste policies and the Green New Deal are increasingly focusing on bio-waste enhancement, in particular within the Bioeconomy Strategy and the Circular Economy Package. Circular bioeconomy (CBE) combines these perspectives, with an increasing focus on organic flows extension and enhancement along the economic cycle. This paper analyses the potential of the CBE paradigm to improve the treatment of the organic fraction of the municipal solid waste (OFMSW), taking the Metropolitan City of Turin (MCT) as a case study. Our results indicate that the currently used OFMSW plant capacity of MCT is insufficient with respect to the need for treatment and, above all, inadequate for future demand trends. We advance an analysis of different CBE-related projects, which contribute to the creation of a feasible environment for bio-based closed loops in Turin. In particular, RePoPP (Porta Palazzo Organic Waste Project) is proposed as an instance of a systemic and circular process that could be improved by following the CBE principles. Through the use of qualitative system dynamics, we propose a decentralised alternative MSW management scenario with a micro anaerobic digestion plant at its core. A stakeholder analysis through a power-interest matrix identifies actors that are key to enabling this scenario. The sustainable pathways proposed in this paper can inspire local-level policy design and therefore contribute to the creation of new systemic food and waste policies for the city through the CBE paradigm.