Selective Removal of Phosphorus from Wastewater Combined with Its Recovery as a Solid-Phase Fertilizer

The influent Total Phosphorus concentration in Municipal Wastewater Treatment Plants (WWTPs) may range from 6–8 mg/L as P. Influx of P into freshwater ecosystems is the primary cause of eutrophication which has many undesirable effects. Therefore, Phosphorus discharge limits for effluents from WWTPs is becoming increasingly common, and may be as low as 0.1 mg/L as P. There is thus a compelling need for technologies that can accomplish this reduction from 8 mg/L to ≤ 0.1 mg/L as P. While precipitation, filtration, membrane processes, Enhanced Biological Phosphorus Removal (EBPR) and Physico-chemical (adsorption based) methods have been successfully used to effect P removal, only adsorption has the potential to recover the P as a usable fertilizer. This benefit will gain importance with time since P is a non-renewable resource and is mined from P-rich rocks. If the current P use trend continues, global P stock will dwindle in the next fifty years. This communication provides details of a process where a polymeric anion exchanger is impregnated with iron oxide nanoparticles to effectuate selective P removal from wastewater and its recovery as a solid-phase fertilizer.