At the Remondis Aqua demonstration plant in Werdohl-Elverlingsen, Germany, phosphoric acid was produced from ashes which were generated by the waterboards Emschergenossenschaft and Lippeverband. This demonstrated the feasibility of phosphorus recovery from ashes with low P-load (3-6%). Further relevant results from this pilot study are:
More than 85% of the contained phosphorus was recovered, meeting future legal obligations to reach a P-recovery rate > 80%
The produced phosphoric acid fulfills the quality criteria of a technical-grade acid fro industrial use.
The by-products, gypsum (construction material) and iron/aluminium salts (precipitant for waste water treatment plans), have low concentrations of contaminants, enabling their recycling.
The leached ashes residue experienced a positive change concerning its disposal characteristics. Its landfill class has been improved by one level compared to the untreated ashes, and therefore the restrictions and costs for disposal are lower.
Based on the collected process data, a concept for industrial implementation of the Remondis TetraPhos - process was established for the central sewage sludge treatment location in Bottrop.
Read more about Remondis Tetraphos® -process: Information sheet in the section "Phos4You documents": www.nweurope.eu/phos4you
See video about P-recovery from sewage sludge ashes: