Water Quality Management

P-Recycling from Wastewater

Phosphorrecycling from Wastewater


Matthias Zessner Emailmzessner(at)


Short description

Phosphorus (P) is an essential element for every organism. For industrial uses, mainly fertilizer production, phosphorus is extracted from rock phosphate mined from natural deposits. However, the quality of rock phosphate has been in decline in recent years due to rising cadmium and uranium content. Furthermore, the worldwide reservoirs of rock phosphate lie in a few, partially politically unstable countries, which is why the EU Commission declared it as a critical raw material in 2014.

Sewage sludge from municipal treatment plants operated with P-removal contains notable amounts of phosphorus and shows great potential for P-recovery. Conventionally this phosphorus is recycled through the direct application of sewage sludge on agricultural land. However, due to potential environmental risks, this practice is losing acceptance, which is why in Austria and some other European countries only small amounts of P contained in sewage sludge are recycled. Therefore, numerous technologies for the safe and clean recovery of P from waste water have been developed in recent years. In the course of this project a variety of these technologies have been analysed in terms of technical, ecological and economical suitability for an efficient P-recovery. Those identified as most promising were technologies which comprise recovery from sludge supernatant as struvite or P-recovery from sewage sludge ash.

Goal of this project is the development of a sound knowledge to be used as a basis for the optimization of Austrian P-management practices. Since 2014 the Institute is providing scientific support for studies on the implementation of full-scale P-recovery plants in Austria.


Files / Reforts for Download:

final report (in German)

PDFPhosphorrückgewinnung aus dem Abwasser


technical reports (in German)

PDFNassPhos: Nasschemische Rückgewinnung von Phosphor aus dem Klärschlamm

PDFPhosphorbilanz Österreich


description of technical processes (in German)

PDFVerfahrensbeschreibung Teil 1

PDFVerfahrensbeschreibung Teil 2