Optimising electrochemical phosphate recovery

Phosphorus (P) is an essential element for life, and our society is mainly dependent on the use of P-derived products. The industrial source for P is phosphate-rich ores (phosphate rock). Unfortunately, known phosphate reserves are scarce. However, substantial amounts of phosphate can be found in our domestic and industrial wastewater originating from food production, consumption, and other manufacturing processes. Previous research has shown that Electrochemical Systems (ES) can recover calcium phosphate (CaP) as hydroxyapatite or amorphous calcium phosphate. CaP recovery relies on the hydrogen evolution reaction at the cathode, which increases the local pH sufficiently for CaP precipitation. Contrary to conventional phosphate removal processes, electrochemical phosphate recovery (EPR) does not require any chemical addition and solely relies on electrical energy. While EPR was proven at a laboratory scale with real wastewater, further insights are needed into this technology for future upscaling and competitiveness. This PhD project will focus on optimising electrochemical phosphate recovery in terms of energy use and recovery efficiency of the system. Therefore, different system designs, material choices, electrode materials, and modifications will be investigated. The optimisation process will involve both experimental and modeling work. Another focus will be the “harvesting” process and product quality of the recovered CaP product. Working under realistic conditions (real wastewater) and collaborating with the participating companies in the “Resource Recovery” theme will allow upscaling the electrochemical phosphate recovery process.