[Effect of intermittent aeration on growth kinetics of nitrifiers and mechanism for NO2- accumulation].
In order to investigate shortcut nitrification, an intermittent-aeration SBR was employed to treat the domestic wastewater containing low concentration of NH4+ . The results shows that under the SRTs of 10, 5, 2.5 and 1.25 d, NO2- produced in effluent were built up to 18, 19, 14 and 5 mg/L, respectively, with accumulation ratio of 73%, 85%, 91% and 78% respectively. As to the continuous-aeration SBR, however, the NO2- accumulation ratios were only 14%, 21%, 31% and 34%. In addition, the corresponding removals of NH4- in the intermittent-aeration SBR were maintained at a comparable level in contrast to those for the continuous-aeration SBR, i.e., 97%, 95%, 76% and 39% vs. 92%, 97%, 71% and 47%. By exploring the growth kinetics of nitrifiers, ammonia-oxidizing bacteria (AOB) in the intermittent-aeration system was capable of increasing its biomass in the reactor by an elevation in growth yield (Y(AOB)), which as a result compensated the decreased specific substrate utilization rate at low DO level and further led to the unchanged microm value and NH4+ oxidation rate. On the contrary, nitrite-oxidizin bacteria (NOB) was lack of the function of compensability, and it hence lowered the microm value and NO2-oxidation rate, and therefore resulted in an accumulation of NO2- in the effluent.
Jiang
Yi-feng
YF
College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, China. jyf@zjut.edu.cn
Chen
Jun
J
Wang
Bao-zhen
BZ
Chen
Jian-meng
JM
D000641:Ammonia / Q000737:chemistry / Q000378:metabolism; D019149:Bioreactors / Q000382:microbiology*; D007700:Kinetics; D008954:Models, Biological; D009573:Nitrites / Q000032:analysis / Q000378:metabolism*; D009576:Nitrobacter / Q000254:growth & development* / Q000378:metabolism; D009606:Nitrosomonas / Q000254:growth & development* / Q000378:metabolism; D010084:Oxidation-Reduction; D014865:Waste Disposal, Fluid / Q000379:methods*
D009573:Nitrites; D000641:Ammonia