Catalyzing the circular economy of critical resources in a national system: Case study on drivers, barriers, and actors in nutrient recycling

Cycling of nutrients, such as phosphorus (P) and nitrogen (N), is essential for all life: Nutrients are crucial for securing societies' food systems and valuable raw materials for industrial processes. Recycling nutrients from various side and waste streams instead of virgin nutrients has attracted considerable interest in the society, particularly as geopolitical and epidemic issues have caused many nations to reconsider how they ensure flows of critical resources by increasing the Circular Economy (CE) principles. This study examines what drivers and barriers catalyze nutrient circulation in national settings, requiring diverse actors to support intentional nutrient recycling. By taking multidisciplinary and ecosystem approaches, we examine diverse sociotechnical drivers and barriers and the actor ecosystem involved. We conduct an extensive qualitative case study on nutrient circulation (P and N) in a Finnish context, analyzing over 150 documents and interviewing over 20 diverse actors (from diverse companies through ministries to farmers) involved in nutrient recycling, from biowaste through agri-cultural biomasses and sludge from municipal wastewater treatment plants. Our study 1) generates an ecosystem actor map uncovering diverse actors enabling nutrient recycling in society; and 2) exposes technological, busi-ness, organizational, regulatory, linguistic, visual, and psychological drivers and barriers shaping nutrient cir-culation. It explains the sociotechnical preconditions for different actor/stakeholder groups to adopt and advocate circular economy (CE) principles for nutrient recycling, which are generalizable to other critical re-sources. The study contributes to CE research and advises practitioners by providing a comprehensive catalyst toolbox to advance nutrient circulation and facilitate its acceptability and diffusion.