title: Fast start-up and controlled operation during a long-term period of a high-rate partial nitrification activated sludge system.
abstract: Partial nitrification of a high-strength ammonium wastewater (1150 +/- 150 mg N-NH4(+) L(-1)), mimicking reject water, was achieved in an activated sludge pilot plant with a configuration of three continuous reactors in series plus a settler. Stable and robust partial nitrification was maintained during 800 days of operation at 30 degrees C with a sludge retention time (SRT) of 8 +/- 3 days. A high volumetric ammonium oxidation rate (2.0 g N L(-1) d(-1)) was obtained with a [N-NO2-]/[N-NO(x)-] ratio of 1, i.e. full nitritation. The start-up of the partial nitrification system was quickly and successfully performed with an on-line control system using municipal wastewater treatment plant (WWTP) sludge as inoculum. An ammonia-oxidizing bacteria (AOB) fraction of 72 +/- 10% was obtained after only 30 days of start-up. The applied SRT of 7-10 days with the combination of free ammonia inhibition and dissolved oxygen limitation provided the selective washout of nitrite-oxidizing bacteria (NOB) and an active nitrifying population with high ammonium oxidizing rates.
authors.affiliation: Departament d'Enginyeria Química, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Barcelona, Spain.
authors.forename: Josep A
authors.initials: JA
authors.lastname: Torà
authors.forename: Javier
authors.initials: J
authors.lastname: Lafuente
authors.forename: Julián
authors.initials: J
authors.lastname: Carrera
authors.forename: Juan A
authors.initials: JA
authors.lastname: Baeza
mesh_terms: D019149:Bioreactors; D005240:Feasibility Studies; D058465:Nitrification; D010865:Pilot Projects; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012722:Sewage / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D000644:Quaternary Ammonium Compounds; D012722:Sewage