Performance Characterization of a Steam Distillation Process for Ammonium Recovery from Urine

Abstract

The purpose of this study was to characterize the nitrogen recovery efficiency of a full-scale prototype nutrient recovery system that processes source-separated urine by the steam distillation of ammonia. Successful operation of the steam distillation process was demonstrated under various operating conditions with an average ammonium mass flow balance accounting for 97%±18% (n = 30) of the ammonium. A range of relative flow rates of urine and steam (urine:steam ratio) ranging from 3.5 to 9.1 were evaluated to establish viable operating conditions and product formulations. The total ammonium recovery in the reactor distillate remained high and was generally greater than 90% at urine:steam ratios lower than 7. Increasing the urine flow rate relative to the steam flow in the distillation column decreased the total ammonium recovery in the distillate but increased the concentration of ammonium in the distillate relative to baseline conditions.