10.1021/acs.est.6b05816.s001 William A. Tarpeh William A. Tarpeh Kai M. Udert Kai M. Udert Kara L. Nelson Kara L. Nelson Comparing Ion Exchange Adsorbents for Nitrogen Recovery from Source-Separated Urine American Chemical Society 2017 wastewater volume urine unit cost decrease ammonium adsorption Nitrogen Recovery 1 week Ion Exchange Adsorbents ion exchange biochar Source-Separated Urine Dowex Mac 3 nitrogen humans adsorption capacity salt solutions Dowex 50 ion exchange reactor volumes Cation adsorption curves wastewater treatment energy input 2017-01-18 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Comparing_Ion_Exchange_Adsorbents_for_Nitrogen_Recovery_from_Source-Separated_Urine/4616209 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.