Capturing Phosphorus from Wastewater: A New Electrochemical Process
Researchers at the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, in Stuttgart, Germany, have developed an electrochemical process to obtain struvite from wastewater without the need to add any chemicals. Instead, the required magnesium is added via a magnesium electrode, which is highly reactive and therefore requires very little energy.The pilot system has a 2m high electrolytic cell through which the wastewater is directed. With a sacrificial magnesium anode and a metallic cathode, the electrolytic process splits the water molecules into negatively charged hydroxyl ions at the cathode. At the anode the magnesium ions migrate through the water and react with the phosphate and ammonium molecules in the solution to form struvite. This has the advantage that it can be used as fertiliser without further processing.