Removal and Recovery of Phosphate from Water Bodies and Reuse as a Fertilizer (RFT-419)

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Invention Summary

beads for phosphate recovery

Scientists at NDSU have developed biodegradable iron-containing alginate beads that remove phosphorus from water, and can then be beneficially reused to provide Phosphate fertilization.  As a result, this dual-use technology can be used to clean water bodies that are eutrophic due to excess phosphorous, then use the phosphorous for fertilization in agricultural, nursery, and greenhouse settings where phosphorus is a limiting nutrient.


  • Phosphorus removal is effective at concentrations as low as 10-100 µg/L (30 µg/L is considered eutrophic)
  • Beads can be placed in porous containers and suspended from the surface so they stay in the zone of highest phosphorus concentration
  • Readily manufactured at commercial scale using standard processes
  • Works well from pH 4 to pH 9, so may be applied across a range of locations and applications
  • Formulations suitable for standing, slow-moving, or rapidly moving water
  • Environmentally-friendly materials – alginate biopolymer, iron, and phosphorus are all suitable for placement in water (in the case of the pristine beads) and application to land (after absorbing phosphorus)


  • Treatment of eutrophic water bodies
  • Industry effluent, wastewater treatment and treatment of feedlot ponds and runoff


Manufacturing a batch of beads takes about 6.5 hours, 30 minutes to form beads and 6 hours for bead hardening. The beads can then be dried in an oven or in open air. The manufacturing process can be fully automated and needs a pump and small diameter tubing that can deliver the liquid alginate drop wise to the bead forming solution. The dry beads are very light in weight and can be packaged in airtight bags or pouches. 


This technology is the subject of Issued US Patent Nos. 9,359,228 and 9,815,710 and is available for licensing/partnering opportunities.


Henry Nowak, Technology Manager


RFT, 419, RFT419

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