title: Operating a pilot-scale nitrification/distillation plant for complete nutrient recovery from urine.
abstract: Source-separated urine contains most of the excreted nutrients, which can be recovered by using nitrification to stabilize the urine before concentrating the nutrient solution with distillation. The aim of this study was to test this process combination at pilot scale. The nitrification process was efficient in a moving bed biofilm reactor with maximal rates of 930 mg N L(-1) d(-1). Rates decreased to 120 mg N L(-1) d(-1) after switching to more concentrated urine. At high nitrification rates (640 mg N L(-1) d(-1)) and low total ammonia concentrations (1,790 mg NH4-N L(-1) in influent) distillation caused the main primary energy demand of 71 W cap(-1) (nitrification: 13 W cap(-1)) assuming a nitrogen production of 8.8 g N cap(-1) d(-1). Possible process failures include the accumulation of the nitrification intermediate nitrite and the selection of acid-tolerant ammonia-oxidizing bacteria. Especially during reactor start-up, the process must therefore be carefully supervised. The concentrate produced by the nitrification/distillation process is low in heavy metals, but high in nutrients, suggesting a good suitability as an integral fertilizer.
authors.affiliation: Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland E-mail: kai.udert@eawag.ch.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Fumasoli
authors.affiliation: Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland E-mail: kai.udert@eawag.ch.
authors.forename: Bastian
authors.initials: B
authors.lastname: Etter
authors.affiliation: Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland E-mail: kai.udert@eawag.ch.
authors.forename: Bettina
authors.initials: B
authors.lastname: Sterkele
authors.affiliation: Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland E-mail: kai.udert@eawag.ch; ETH Zürich, Institute of Environmental Engineering, 8093 Zürich, Switzerland.
authors.forename: Eberhard
authors.initials: E
authors.lastname: Morgenroth
authors.affiliation: Eawag, Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland E-mail: kai.udert@eawag.ch.
authors.forename: Kai M
authors.initials: KM
authors.lastname: Udert
mesh_terms: D000641:Ammonia / Q000032:analysis; D018441:Biofilms; D019149:Bioreactors; D057168:Distillation; D005308:Fertilizers; D058465:Nitrification; D009573:Nitrites / Q000032:analysis; D009584:Nitrogen; D010865:Pilot Projects; D014556:Urine
chemical_list: D005308:Fertilizers; D009573:Nitrites; D000641:Ammonia; D009584:Nitrogen