Session 6

Opportunities and challenges to closing the Phosphorus supply chain through Phosphorus recovery from wastewater in European urban areas. A case study on Stockholm, Sweden and Budapest, Hungary
Claudiu Eduard Nedelciu1, Krístin Vala Ragnarsdóttir1, Ingrid Stjernquist2
1University of Iceland, Iceland; 2University of Stockholm, Sweden

Phosphorus (P) is one of the three irreplaceable fertilisers needed for agricultural production. Most of the P fertilisers come from phosphate rock, a finite resource obtained by surface mining in countries like the US, China and Morocco. Once applied on farms, a part of the P is absorbed by crops for growth, while another part leaks into waterways causing eutrophication in surface waters, coastal zones and inland seas. P is also found in sewage and it is an important component in urban wastewater, further contributing to eutrophication of water resources.
This paper investigates the degree to which urban areas can reinvent their role from main P pollution and P loss hubs into hotspots of P recovery through a circular system, by exploring the socio-economic processes needed for such a transformation. An increase in population and food production will potentially increase P pollution from agricultural runoff and sewage. By using system analysis and qualitative research methods we explore the role of P recovery from urban areas as a means to move towards circular P nutrient cycle. P recovery from urban wastewater is already being implemented throughout Europe and several countries have already set up a series of successful projects, some at a large scale. Preliminary results indicate that up to 90% of P can be recycled from sewage sludge, bringing down the need for primary resource extraction, lowering import costs, and reducing harmful environmental pollution. Studies show that Europe, which at present imports 92% of its P fertilisers, could recover up to 15% of its total P need from urban sludge. This study explores the dynamics of pilot projects in Stockholm and Budapest, in order to determine their efficiency, applicability and upscalability and advance suggestions for innovative solutions to close the urban P cycle in Europe.