Patent ID: 7622047
Filing Date: 2009-11-24
Classification: B01D,C02F,Y10S

Abstract:
1. A method for extracting one or both of phosphorus and nitrogen from wastewater, the method comprising: introducing the wastewater into a column comprising a substantially vertically oriented conduit having a harvesting section and at least two vertically sequential sections above the harvesting section, wherein a cross sectional area of the conduit increases between adjacent ones of the sections; maintaining supersaturation conditions for struvite, a struvite analog, or a phosphate compound in the harvesting section; recycling wastewater which has passed through the column while controlling a supersaturation ratio of struvite, a struvite analog, or a phosphate compound in the harvesting section to have a value within a desired range to produce pellets of said struvite, struvite analog, or phosphate compound, wherein controlling the supersaturation ratio is performed at least in part by controlling with a process controller a recycling ratio of a rate at which wastewater is recycled into the column to a total rate at which wastewater is being introduced into the column; and, extracting from the harvesting section said pellets formed within the column.