AirPrex® Projects

AirPrex®: Sludge Optimization and P-Recovery

Struvite Mineral Buildup Leads to Reduced Plant Capacity

In wastewater reclamation plants with Biological Phosphorus Removal (BPR), phosphorus accumulates in sludge and releases in a dissolved reactive form (orthophosphate) in an anaerobic condition. Elevated orthophosphate levels in sludge causes operational challenges, including

  • Deterioration of sludge dewaterability
  • Elevated phosphorus load to the wastewater treatment plant due to phosphorus recirculation
  • Uncontrolled formation of struvite (or MAP: magnesium ammonium phosphate) inside pipes and other equipment
  • Reduced digester capacity by struvite build-up inside the anaerobic digester

AirPrex Optimizes the Sludge Treatment Process
Like No Other System

AirPrex turns struvite into an opportunity for resource recovery. Struvite, when formed under a controlled environment, can be harvested and utilized as a beneficial fertilizer. AirPrex forms struvite by stripping out CO2, elevates the pH and adds MgCl2 to augment Mg2+. AirPrex installs between the anaerobic digester and the dewatering equipment. The process converts the orthophosphate into struvite crystals, which is harvested from the bottom of the reactor. AirPrex mitigates the unexpected consequence of dewatering Bio-P sludge.

AirPrex Removes Struvite while Significantly Improving Treatment Efficiency

     Reduce Polymer Consumption up to 30%
     Reduce Disposal Costs up to 20%
     Reduce Phosphate Recycle Load up to 90%
     Reduce Maintenance Costs up to 50%
     Increase Revenue from Fertilizer up to 20%