Removal and recovery of phosphate from eutrophic lakes and wastewater; reuse of recovered phosphate as fertilizer


Researcher: Achintya N.

Project sponsors: North Dakota Department of Commerce (ND DoC), (09/2014-09/2017)


Phosphorus is one of the most essential nutrients for plant growth, and without phosphorus there will be no healthy plants and hence food. It is predicted that the phosphate supply will fall below the demand for agriculture by 2033, and that raises a major food security concern. On the other hand huge amounts of phosphorus (in the form of phosphate) is wasted due to unsustainable user practices. Phosphates applied in agriculture runs off to water bodies and accumulates there. The excess of phosphorus in water leads to eutrophication (or graduate death) of lakes and that impacts the ecosystem and local economy. The United States has about 25,000 lakes which are either eutrophic or hypereutrophic and they need immediate (and subsequent) clean-up to make the lakes productive and their water usable. This proposed project aims at evaluating the commercial feasibility of the novel iron cross-linked alginate (FCA) beads invented by the Principal Investigator (PI) for phosphate removal from water bodies and use of the phosphate-containing FCA beads as a slow release phosphate fertilizer for agriculture. There is substantial interest in the government and private sectors in removing the excess phosphorus to make the lakes productive as well for the use of recovered phosphate in agriculture. The FCA beads  developed by the PI will find immediate use in eutrophic lakes in addition to being used for secondary treated municipal wastewater phosphate recovery. The PI has done laboratory-scale experiments and established that FCA beads work very well for both low (<100 micro gram/L) and high (5-100 mg/L) concentrations of phosphate present in water. The current project evaluated the feasibility of developing a marketable product from the PI's patent pending invention (FCA beads) for the removal, recovery, and reuse of phosphate. The PI conducted additional experiments to scale-up the production of FCA beads, used them under conditions similar to the field environment (e.g., actual lake water, high flow, lake waves), and evaluate the bead’s shelf-life. 


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