Selective removal of phosphate from wastewater using ion exchange resin beads
Advisor: Sukalyan Sengupta
Eutrophication of surface waters, caused by high concentrations of Phosphorus (P), has become an urgent concern for water quality managers. Recent regulations impose much stricter limits on P leaving wastewater treatment plants. Primary/secondary treatment methods do not adequately reduce the amount of phosphate, and the more common tertiary methods have many limitations, including high costs and low removal rates.
DOWEX M4195 chelating resin beads, when coated with hydrated ferric oxides (HFO) and loaded with copper, have been shown in previous experiments to have both a high selective affinity and high adsorption rate for P. Several experiments were used to determine sorption capacity, rate of uptake, and performance under various conditions. Experiments show that the DOW-HFO-Cu resin can selectively remove trace amounts of P from solutions containing high background concentrations of sulfate, chloride, and other anions. After exhaustion, the resin can be regenerated and stripped of P, which can be collected in the form of high-grade fertilizer (struvite). The resin beads and regenerant can be reused multiple times, creating a sustainable closed-loop process.