Overview of recent advances in phosphorus recovery for fertilizer production.

This Mini Review gives an overview of and respective references for the current situation regarding global phosphorus reserves and the legal situation for P recovery using Germany as the model. Apart from the well-known pilot up to industrial/full scale recovery techniques, emerging chemical and bio-based P recovery techniques are named without claiming to be all-encompassing. Special attention is paid to the biological systems for P recovery that reveal ways for use of renewable resources as raw materials. A few chemically based recovery techniques like AirPrex®, (Ostara)PEARL™, AshDec®, and RecoPhos® have already been used to recover P at a rate and quality which allows for its sale as a fertilizer. Many chemically based processes are at the stage of investigation on a pilot or laboratory scale, e.g. P-RoC, LeachPhos, and Mephrec®. All of the biologically based technologies like P-Bac are still at an early stage of research and show promising results. Of all recovered materials struvite, calcium phosphate and biological bound phosphorous seem to have the best plant availability. Although there is no ultimate "one fits all" technology, potential P-recovery plant operators can choose from a wide range of techniques which will best fit local raw material availability, economic and ecological situation.