Prozessentwicklung für die simultane Rückgewinnung von Ammonium und Phosphat aus Abwässern

Translated title of the contribution: Process Development for Simultaneous Recovery of Ammonium and Phosphate from Wastewater

Sandro Pesendorfer

Research output: ThesisDoctoral Thesis


The ion exchange loop stripping (ILS) process was developed to recover nitrogen in form of ammonium (NH4+) from the liquid phase of mechanical sludge dewatering at a municipal wastewater treatment plant. NH4+ removal is based on the principle of ion exchange on natural zeolite (main mineral is clinoptilolite) and a subsequent regeneration with caustic soda. Besides nitrogen, phosphorus is another essential nutrient, which is present in wastewater and is degraded unused at wastewater treatment plants. In this work, the NH4+ exchange mechanism was kinetically modeled at laboratory scale to define potential optimization approaches for the existing ILS process. Based on the exchange kinetics, a process for simultaneous recovery of ammonium (NH4+) and phosphate (PO43-) from aqueous solutions using natural zeolite was developed. The PO43- removal mechanism was identified as a surface precipitation reaction of PO43- ions and the calcium ions (Ca2+), which were desorbed from zeolite due to NH4+ ion exchange. Here, the pH of the solution is the rate-controlling parameter in the surface precipitation of Ca2+ and PO43-. Experiments carried out, that zeolite loadings up to 6.78 mg PO43- g-1 and 15.92 mg NH4+ g-1 were reached and after regeneration 75% of the dissolved PO43- were recovered, respectively. It was further shown that simultaneous removal of PO43- had no effect on NH4+ removal onto zeolite. The results in the laboratory show that simultaneous recovery of NH4+ and PO43- using natural zeolite is possible and thus represents a great potential for the stepwise scale up of the ILS process to the ILSplus process.
Translated title of the contributionProcess Development for Simultaneous Recovery of Ammonium and Phosphate from Wastewater
Original languageGerman
Awarding Institution
  • Montanuniversität
  • Weiß, Christian, Assessor B (internal)
  • Lehner, Markus, Supervisor (internal)
  • Fuchs, Werner, Assessor A (external), External person
  • Pomberger, Roland, Co-Supervisor (internal)
Publication statusPublished - 2022

Bibliographical note

no embargo


  • wastewater treatment
  • ammonium
  • phosphate
  • nutrient recovery
  • zeolite

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