Struvite Extraction
Phosphorus Recovery as Struvite
Struvite is formed from liquid dairy manure after anaerobic digestion at extraction efficiencies of 60 to 80%. The current focus is to achieve high rates of extraction efficiency at a low cost of production. Can phosphorus be removed from liquid dairy manure for off-farm transport? On most dairy farms the amount of phosphorus in dairy manure in excess of what can be used for crop production. Continued application of the manure at nitrogen based rates can result in build-up of phosphorus in soil. Once the soil is saturated with phosphorus it then is at risk of loss to surface and ground water.
Approach
Utilize a fluidized bed technology to remove phosphorus from liquid dairy manure in the form of struvite. Struvite is an “easy to handle” form of slow release phosphorus which can be shipped off farm. The chemical formula for struvite is MgNH4PO4·6(H2O).
