Recovery of Ammonium from Biomass-Drying Condensate Via Ion Exchange and Its Valorization as a Fertilizer

Abstract

In this study, an industrial biomass-drying wastewater condensate containing > 3200 mg/L NH4+ and >8900 mg/L CH3COO− was treated in ion-exchange columns for the recovery of NH4+. Two commercial resins (CS12GC and CS16GC) were studied on laboratory and pilot scales. CS16GC outperformed CS12GC by achieving better separation at the condensate temperature (60 °C), which was energy-efficient regarding NH4+ removal. K3PO4 was used for regeneration to produce a liquid compound fertilizer containing nutrient elements (N, K, and P) as a byproduct. The N/K ratio in the byproduct was found to be adjustable by varying the operating parameters. Regeneration with 2 mol/L K3PO4 gave a higher regeneration efficiency (97.67% at 3 BV and ~100% at 4 BV). The stability tests performed on a laboratory scale showed that the cyclic runs of the column separation process were steady and repeatable. Based on the outcomes of the laboratory-scale tests, the pilot-scale tests applied a loading volume of 7 BV. The pilot column purified the feed and achieved the target NH4+ level in the treated effluent within the seven tested cycles, revealing that the industrial application of the cation ion-exchange resin CS16GC is worth further study.