Pearl® - Phosphorus recovery from waste water 

Phosphorus recovery from wastewater with Pearl®

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Phosphorus recovery with Pearl® technology 

Phosphorus removal from wastewater is very costly. The Pearl® technology combines 90% phosphorus removal with phosphorus recovery to produce a high-value fertilizer. The Pearl® technology is a cost-effective solution for phosphorus removal and contributes to sustainable phosphorus recycling.

The Pearl® technology can be very well applied in wastewater treatment plants running enhanced biological phosphorus removal along with a digester and dewatering facilities. In the process, phosphate and nitrogen are converted to struvite mineral pellets of 99.9% purity called Crystal Green® fertilizer. The Pearl® process fully replaces chemical phosphorus removal and increases nitrogen removal capacity of the wastewater treatment plant, generating substantial cost savings and increased plant performance.


  • Economic nutrients recovery process. 
  • Revenues from Crystal Green® fertilizer. 
  • Savings on chemicals and sludge disposal. 
  • Better effluent quality on phosphate and nitrogen. 
  • Better overall plant performance and stability.
  • Easy to fit in existing wastewater treatment plants.

Investment or lease?
The operational benefits and the revenues from Crystal Green® sales translate into a short pay back time on investment. Alternatively, there is no need to invest at all if the Client chooses to lease the Pearl® system instead (Treatment Fee Model). The Client pays a monthly fee based on agreed performance on phosphate removal. The Treatment Fee Model guarantees immediate operational savings at the lowest possible risk.

Crystal Green®
The struvite pellets are traded as Crystal Green® premium ready-to-use fertilizer product. Crystal Green® is a ‘slow release’ fertilizer that gradually releases phosphorus and nitrogen to the crops leading to better nutrient up-take and reduced quantity of fertilizer needed.

Value of phosphorus
Phosphorus is an important fertilizer constituent and a key element in the food chain. The world phosphorus needs are still rising and shortage is expected in near future, underlining the urgency for recovery. The Pearl® technology is a recovery process working at a high level of performance, creating value from waste.

The Pearl® technology was developed to full-scale and introduced in North America by Ostara Nutrients Recovery Technologies Inc. (Canada).

Pearl® - Phosphorus recovery from waste water

Christa Morgenschweis Christa Morgenschweis, Advisor Water, Grontmij in the Netherlands
Water advisor, Grontmij in the Netherlands
+31 888 11 59 36