Circular chemistry in response to the phosphate crisis

Abstract

Raw phosphate is used as a raw material to produce phosphorus-based fertilizers, and its supply shortage could negatively impact the global food supply. The European Commission has classified this raw material as critical in terms of estimated stocks. For years, new resources have been explored as substitutes for the phosphate component in fertilizer production and other phosphorus-containing products. An alternative has emerged in the possibility of using ash obtained from incineration of sludge generated in the process of municipal wastewater treatment. This work presents analyses of such ash as a case study for determination of potentials for partial replacement of raw phosphates in mineral fertilizers. It was shown that the ash contains high P2O5 content, which indicates this type of sludge as a promising alternative raw material in fertilizer production. The obtained results are significant for the Republic of Serbia as it is planned to construct over 300 wastewater treatment plants by 2041, with projection of about 135,000 t/year sludge generation. The presented analysis of ash obtained from this type of sludge justifies construction of incineration plants as the one planned in Prahovo, Serbia, which will by waste treatment contribute to circular economy and chemistry.

Keywords

• mineral fertilizers
• circular economy
• phosphorus component
• ash valorization