Pre-Digestion P-Recovery

High-Efficiency P-Recovery and Digester Protection

Fermentation: the Biological Solution for Phosphorus Solubilization

CalPrex works with high concentrations of soluble phosphorus and is a viable solution for utilities seeking to mitigate operations and maintenance issues related to struvite scaling and poor sludge dewaterability.

The end recovered product, brushite, is a fertilizer comparable to leading phosphate fertilizers on the market today.

VIEW OUR PILOT TESTS

This high-value solution is for facilities needing phosphorus removal and recovery:

• Prior to thermal hydrolysis
• From waste activated sludge and/or primary sludge prior to anaerobic digestion
• From aerobic or post-aerobic digestion (PAD)

CalPrex reactor sits between the fermentation tank and gas phase digesters.

• Facilitates the rapid release of soluble phosphorus in Bio-P sludge along with the dissolution of crystalized and organically-bound phosphorus
• Over 60% solubilization of P can occur in the fermentation without using any additional chemicals
• In non-Bio-P plants, up to 40% of the phosphorus solubilizes using a fermentation step

Fermented sludge is dewatered

Centrate is sent to the CalPrex reactor

• Centrate precipitates the dissolved phosphorus with the addition of calcium hydroxide
• Maintains the solution around 6.5 pH
• Recovers phosphorus as a brushite crystal (CaHPO₄•2H₂O)

Contact Centrisys/CNP for pilot testing capabilities.