title: Model-based study of nitrite accumulation with OUR control in two continuous nitrifying activated sludge configurations.
abstract: Achievement of partial nitrification relies on the different characteristics of the microorganisms involved in the two steps of nitrification (AOB, ammonium oxidizing bacteria and NOB, nitrite oxidizing bacteria). Several configurations and conditions have been used to achieve partial nitrification taking into account their different responses in front of some environmental conditions like pH, temperature (T), dissolved oxygen (DO) and the inhibitory compounds free ammonia (FA) and free nitrous acid (FNA). This work is a theoretical study about the utilization of a control strategy based on controlling OUR by manipulating the influent flow-rate together with additional changes in T, pH or DO for achieving stable partial nitrification. Two different configurations were simulated. Configuration A consisted of three continuous stirred-tank reactors in series plus a settler, while configuration B consisted of a single reactor with the same total volume and a settler. The developed control system was shown as a good tool to achieve partial nitrification with both configurations. Nevertheless, configuration A showed better results and partial nitrification was obtained even under theoretically unfavourable conditions as T = 15 degrees Celsius, pH = 8.3 and DO = 3 mg O(2) L(-1).
authors.affiliation: Department d'Enginyeria Química, Escola d'Enginyeria, Universitat Autònoma de Barcelona, Bellaterra 8193, Spain.
authors.forename: Irene
authors.initials: I
authors.lastname: Jubany
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: Baeza
authors.forename: Javier
authors.initials: J
authors.lastname: Lafuente
authors.forename: Julian
authors.initials: J
authors.lastname: Carrera
mesh_terms: D019149:Bioreactors; D003198:Computer Simulation; D008954:Models, Biological; D009573:Nitrites / Q000737:chemistry* / Q000378:metabolism*; D010101:Oxygen Consumption; D010865:Pilot Projects; D012722:Sewage / Q000382:microbiology*; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000378:metabolism*; D018508:Water Purification / Q000379:methods
chemical_list: D009573:Nitrites; D012722:Sewage; D014874:Water Pollutants, Chemical