The circular economy and agriculture: new opportunities for re-using Phosphorus as fertilizer

The increasing demand of phosphorus (P) worldwide is posing important challenges on the market stability of fertilizers. Extracting more P would not guarantee high P quality and low prices. Globally, only the European Commission, in a recent document about the Circular Economy strategy, has begun to address the challenge of the dependence on phosphate rock. Based on a simple circular economy theoretical framework, this paper proposes an impact analysis of the use of recycled P as a substitute of chemical P fertilizers. Two new technologies applied to retrofit existing wastewater treatment plants (WWTP) are considered: Moving-Bed Bio-Reactors and Struvite Crystallization Modules. The analyses indicate that the introduction of these technologies prove to be economically sustainable for specific levels of inhabitant equivalent (IE) and that the profitability of struvite, as a substitute of chemical P, increases with increasing levels of P fertilizer prices and for increasing sizes of WWTPs.