Proceedings

Phosphorus: a pollutant or a resource?

P recovery from sludge liquors Struvite chemical precipitation + Well known process installed at full-scale with a market +/- Recovery of 90% of phosphorus (10% left in the wastewater) – Needs high phosphorus streams >100 mg/L – Crystallisation through chemical process with chemical addition

Conclusions

• Bacteria can produce struvite crystals in wastewater in simple way (no optimisation yet!)
• Microscope analysis showed presence of crystals as early as 3 days and visible crystals were seen in cultures after 10 days reaching up to 250 µm.
• Crystals can be separated by filtration/centrifugation
• The final concentration of phosphate in sludge centrifuge liquors reached 1.5 mg/L, indicating a 95% P and 55-86% ammonia removal
• The process can potentially be economically attractive