High-Efficiency Phosphorus Recovery and Digester Protection

Maximize Phosphorus Recovery with Minimal Sludge Protection

CalPrex Process

• Harnesses fermentation to acidify bio-P sludge
• Solubilizes over 65% of phosphorus in the fermentation process
• Isolates the soluble phosphorus (PO₄-P) in the dewatered fermented
  sludge centrate
• Precipitates soluble phosphorus (PO₄-P) by calcium hydroxide in the
  reactor
• Maintains the solution around 6.5 pH
• Recovers phosphorus as brushite (CaHPO₄· 2H₂O), a market-ready,
  high-quality fertilizer

MagPrex Process

• Converts the remaining soluble phosphate (PO₄-P) in digested sludge to
  struvite (MgNH₄PO₄· 6H₂O)
• Air strips CO₂ and adds magnesium chloride
• Recovers phosphorus as struvite, a market-ready fertilizer
• Reduces the phosphorus recirculation by 90%