Phosphorus is an essential and irreplaceable plant nutrient. Globally declining phosphorus reserves, which are increasingly contaminated with heavy metals, are limited to a few politically unstable regions outside Europe. The EU Commission has therefore already classified phosphorus as a critical raw material in 2014, which should provide an incentive for recycling activities.
High phosphorus contents in municipal waste water or sewage sludge offer recovery from these material flows and will therefore be prescribed in future by the sewage sludge ordinance. At the same time, treatment of sewage sludge in established recycling and disposal paths, such as co-incineration or direct agricultural use, will be restricted. New recycling concepts to be developed for environmentally compatible and safe disposal must not stand in conflict with obligatory recovery of phosphorus contained in sewage sludge.
In the region Rur, Erft, Cologne the WVER, Erftverband and StEB Köln will cooperate in sewage sludge treatment in future. By building a common mono-incineration plant, an independent, secure treatment possibility is to be created. However, due to very high technical and economic uncertainties and risks, subsequent recycling of phosphorus concentrated in ashes has not yet been clarified.
PhoREKA, a project funded by the BMBF (German Federal Ministry of Education and Research), aims at realising regional phosphorus recycling. In a concept phase, TEER, WVER, Erftverband and StEB Köln will jointly investigate fundamental questions regarding the selection of processes and region-specific requirements. Results will be considered in planning a possible subsequent implementation phase.