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Order for a mobile pilot plant for phosphorus recovery

AirPrex®-Macro in a 40 ft Container for PARFORCE-Project of the TU Bergakademie Freiberg

Within the framework of the project „PARFORCE“, funded by the EXIST research transfer funding program of the Federal Ministry of Economic Affairs and Energy, the Institute for Technical Chemistry of the TU Bergakademie Freiberg developed a process that refines sewage sludge ash as well as struvite to high purity phosphoric acid.

The processing of struvite produces magnesium chloride as a by-product which, as a source of magnesium, can again be used to produce struvite at sewage treatment plants. The process is suitable to meet the future phosphorus recovery obligation according to the waste sewage sludge ordinance. The extraction of struvite for the fulfilment of this ordinance is particularly suitable in sewage treatment plants, where relatively low phosphorus contents in sewage sludge are measured and a recovery from sewage sludge ash becomes disproportionately expensive.

To demonstrate that struvite can be adequately separated, PARFORCE has chosen the AirPrex® Macro process in combination with a special sewage sludge disintegration. The AirPrex® Macro process enables the highest recovery rates and, due to the crystal’s properties, a struvite that is easy to process with phosphoric acid. This is ensured by increased phosphate re-dissolution in a reaction tank installed in addition to the AirPrex® reactor, in which crystal growth is optimized. The return of small crystals (microcrystals) from the additional reactor back into the AirPrex® reactor achieves the high struvite yield and separation.

Customers choose our solution because it ensures good results not only in phosphate recovery, but in sludge dewatering as well, enabling additional savings (flocculant consumption, disposal costs, maintenance costs, etc.).