title: Comparing Ion Exchange Adsorbents for Nitrogen Recovery from Source-Separated Urine.
abstract: Separate collection of urine, which is only 1% of wastewater volume but contains the majority of nitrogen humans excrete, can potentially reduce the costs and energy input of wastewater treatment and facilitate recovery of nitrogen for beneficial use. Ion exchange was investigated for recovery of nitrogen as ammonium from urine for use as a fertilizer or disinfectant. Cation adsorption curves for four adsorbents (clinoptilolite, biochar, Dowex 50, and Dowex Mac 3) were compared in pure salt solutions, synthetic urine, and real stored urine. Competition from sodium and potassium present in synthetic and real urine did not significantly decrease ammonium adsorption for any of the adsorbents. Dowex 50 and Dowex Mac 3 showed nearly 100% regeneration efficiencies. Estimated ion exchange reactor volumes to capture the nitrogen for 1 week from a four-person household were lowest for Dowex Mac 3 (5 L) and highest for biochar (19 L). Although Dowex Mac 3 had the highest adsorption capacity, material costs ($/g N removed) were lower for clinoptilolite and biochar because of their substantially lower unit cost.
authors.affiliation: Department of Civil and Environmental Engineering, University of California , Berkeley, California 94720, United States.|Engineering Research Center for Re-inventing the Nation's Urban Water Infrastructure (ReNUWIt), Stanford, California, United States.
authors.forename: William A
authors.identifier: 0000-0002-2950-526X
authors.initials: WA
authors.lastname: Tarpeh
authors.affiliation: Eawag, Swiss Federal Institute of Aquatic Science and Technology , 8600 Dübendorf, Switzerland.
authors.forename: Kai M
authors.initials: KM
authors.lastname: Udert
authors.affiliation: Department of Civil and Environmental Engineering, University of California , Berkeley, California 94720, United States.|Engineering Research Center for Re-inventing the Nation's Urban Water Infrastructure (ReNUWIt), Stanford, California, United States.
authors.forename: Kara L
authors.initials: KL
authors.lastname: Nelson
mesh_terms: D000327:Adsorption; D064751:Ammonium Compounds; D005308:Fertilizers; D006801:Humans; D007474:Ion Exchange; D009584:Nitrogen; D014556:Urine; D014865:Waste Disposal, Fluid
chemical_list: D064751:Ammonium Compounds; D005308:Fertilizers; D009584:Nitrogen