Despite Africa controlling the vast majority of the global phosphate it also faces the greatest food shortages - partially due to a lack of access to the fertilizer market. A more accessible source of phosphorus comes from wastewater flows, which is currently lost through the discharge to open surface waters. Analysing the potential phosphorus production of urban and livestock wastewater in meeting partial agricultural demand for phosphorus can improve food security, reduce consumption of unrenewable phosphorus, reduce pollution, and aid the transitioning to a circular economy. In this study, a global overview is provided where a selection of P-production and P-consumption sites have been determined using global spatial data. Distances, investment costs and associated carbon footprints are then considered in modelling a simple, alternative trade network of struvite phosphorus flows. The network reveals potential for increasing the phosphorus security through phosphorus recycling in particularly the South Africa, Lake Victoria and Nigeria regions. Given Africa's rapid urbanization, phosphorus recovery from wastewater will prove an important step in creating sustainable communities, protecting the environment while improving food security, and so contributing to the United Nations 2030 Agenda for Sustainable Development.

Phosphorus is a nutrient necessary for the development of crops and is thus commonly applied as fertilizer to sustain agricultural production. It occurs naturally, in indefinite quantities of uncertain quality in phosphate rock formations, but also accumulates in urban and livestock wastewater wherefrom it is often lost as a pollutant. Recovering phosphorus from wastewater, however, is feasible through struvite crystallization technologies and has the potential to reduce phosphorus pollution of the environment as well as lower the agricultural demand for artificial P fertilizers. In this study, we developed a model to assess the global potential of P fertilizer recovery from wastewater and to visualize its trade at sub-national resolution. Results show that humans discharge a maximum of 3.7 Mt P into wastewater, thereby potentially satisfying 20 % of the global fertilizer demand. Provided 2015 market dynamics, however, the model determines that only 4 % of this discharge is technologically and economically recoverable in a market that offers cheap rock phosphate products also. The results of this study demonstrate that in the current economic context, phosphorus recovery from wastewater offers only a small contribution to resolving global phosphorus issues. Nevertheless, this recovery offers many wastewater treatment facilities the opportunity to contribute to creating sustainable communities and protecting the environment locally, while reducing their own operational costs.