Phosphor: Eine kritische und zugleich unzureichend genutzte Ressource der Abwasser- und Abfallwirtschaft – Stand des Wissens und Ausblick für Österreich und Europa

Abstract

Currently, the phosphorus (P) used in Austria is essentially of a linear structure. Cyclical ring structures—with the exception of those in manure (slurry, dung) used for local agricultural purposes—are as yet rudimentary. Simultaneously, Austria is entirely dependent on imports of the raw material rock phosphate, partly from geopolitically unstable regions. In contrast, sewage and animal meat and bone meal as significant sources of P are largely ignored. In view of the importance of P, numerous technologies for targeted P recycling from sewage have been developed—some already operational from a purely technical perspective and others already implemented on an industrial scale (particularly, recycling from the liquid phase). In order to make the best possible use of sewage-borne P, recycling from pure sewage sludge or animal meat and bone meal ash combined with sewage sludge ash would be desirable in future. Necessary structures, such as incinerators for sewage sludge alone or in combination with animal meat and bone meal, however, have yet to be developed. In addition to newly developed methods, recyclates (materials that are recyclable) from recycling processes (e.g., struvite), pure sewage sludge ash or animal meat and bone meal ash can be used as secondary raw materials in existing industrial processes, for instance, in the fertilizer or phosphoric acid industries. Neighboring countries Germany and Switzerland already recycle P from sewage sludge and sewage sludge ash to legally binding targets. Implementation in Austria too would initially require (political) commitment and, consequently, changes in the legal framework (e.g., fertilizer legislation) as well as binding standards. Implementation instruments for P recycling could be, for instance: defined recycling quotas for the fertilizer industry (e.g., “Pxx”, according to the E10 bioethanol quota); or levying “phosphorus cents” additional to the sewage treatment and waste management fees, to be used to develop the necessary structures (e.g., incinerators for sewage sludge and animal meal).