Operating parameters for high nitrite accumulation during nitrification in a rotating biological nitrifying contactor.
Incomplete nitrification was studied in a completely and partially submerged rotating biological contactor (RBC). In a partially submerged RBC without additional aeration, 50 to 90% nitrite accumulation (alpha) was achieved at rotation speeds (omega) of 2 to 18 min(-1). In a completely submerged RBC operating during 80 days, a higher alpha of 96% was achieved at omega = 2 min(-1). Incomplete nitrification in a completely submerged RBC at oxygen concentrations of 1.5 to 6.8 mg O2/L indicated that the mass transfer of oxygen is rate-limiting. Modeling of the completely submerged RBC predicts that the oxygen profile will not penetrate the biofilm more than 30 microm, thereby strongly limiting the nitrite-oxidizer growth and causing high nitrite accumulation. Molecular analysis (i.e., fluorescence in situ hybridization) indicated that the nitrite-oxidizers are superficially located (<200 microm) and that the ammonia-oxidizers comprise up to approximately 800 microm of the biofilm.
Antileo
Christian
C
Department of Chemical Engineering, Universidad de La Frontera, Casilla 54-D, Temuco, Chile. cantileo@ufro.cl
Roeckel
Marlene
M
Lindemann
Jörg
J
Wiesmann
Udo
U
D000641:Ammonia / Q000737:chemistry / Q000378:metabolism; D018441:Biofilms; D019149:Bioreactors; D007220:Industrial Waste; D009573:Nitrites / Q000737:chemistry / Q000378:metabolism*; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D012722:Sewage / Q000737:chemistry / Q000382:microbiology; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods*
D007220:Industrial Waste; D009573:Nitrites; D012722:Sewage; D000641:Ammonia; D010100:Oxygen