Phosphorus recovery from hydrothermal carbonization of organic waste: a review

Background This review sheds light on the topic of phosphorus (P) recovery from hydrothermal carbonization (HTC) of organic waste. The paper focuses on the rising need for securing alternative P sources for the increasing demand, in addition to the development of HTC as a thermochemical technique for waste valorization. Results This article studies the definition of P‐recovery from HTC, while introducing the notion of availability, which is a significant factor for studying the efficiency of P‐recovery. A brief comparison between different treatment techniques for P‐recovery from waste streams is presented, and the advantages of HTC are highlighted among different thermochemical techniques. Furthermore, the mechanisms of P‐transformation during HTC reactions are studied, and the effect of various parameters on P‐destination and recovery is emphasized. Finally, applications of P‐recovery from HTC products on the laboratory and industrial scales are studied to assess the feasibility of the application. Conclusion In short, the paper offers a detailed insight into the definition, mechanism, and potential feasibility of P‐recovery from HTC of organic wastes within the scopes of resource management, waste valorization, and fertilizer production. Even though HTC for P‐recovery from organic waste has been applied on laboratory and industrial scales, several challenges persist towards optimizing this process. The paper concludes that adopting P‐availability as a criterion for efficiency is necessary to optimize HTC conditions for P‐recovery. Further studies on P‐transformation during later‐stage reactions of HTC are recommended, as well. © 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).