Manser Reto, Gujer Willi, Siegrist Hansruedi
Swiss Federal Institute of Aquatic Science and Technology (Eawag), CH-8600 Dübendorf, Switzerland.
Water Res. 2005 Nov;39(19):4633-42. doi: 10.1016/j.watres.2005.09.020.
The influence of membrane separation and mass transfer effects on the kinetics of nitrifiers was evaluated by running a membrane bioreactor (MBR) and a conventional activated sludge (CAS) plant in parallel. Both pilot plants were operated at the same sludge age and treated the same domestic wastewater. The half-saturation constants for the substrate were low in both MBR and CAS and did not differ significantly between the two processes (K(NH(4))) and 0.14+/-0.10 g(N)m(-3) and (K(NO(2))) and 0.28+/-0.20 g(N)m(-3) for the MBR and CAS, respectively). However, the half-saturation constants for oxygen exhibited a major difference between the two processes for both the ammonia-oxidizing (AOB) and nitrite-oxidizing (NOB) bacteria. The experiments yielded K(O,AOB)=0.18+/-0.04 and 0.79+/-0.08 g(O2) as well as K(O,NOB)=0.13+/-0.06 and 0.47+/-0.04 g(O2) m(-3) (substrate only NO(2)) for the MBR and CAS, respectively. The higher K(0) values of the CAS were attributed to mass transfer effects within the large flocs prevailing in the conventional system. In contrast, the sludge from the MBR consisted of very small flocs for which the diffusion resistance can be neglected. On the basis of these results, the implementation of mass transfer effects in activated sludge models is discussed and consequences for the operation of MBRs are highlighted.
通过同时运行膜生物反应器（MBR）和传统活性污泥法（CAS）处理厂，评估了膜分离和传质效应对硝化细菌动力学的影响。两个中试厂均在相同的污泥龄下运行，并处理相同的生活污水。MBR和CAS中底物的半饱和常数均较低，且两个工艺之间无显著差异（MBR和CAS的K(NH(4))分别为0.14±0.10 g(N)m(-3)和K(NO(2))分别为0.28±0.20 g(N)m(-3)）。然而，对于氨氧化细菌（AOB）和亚硝酸盐氧化细菌（NOB），两个工艺中氧的半饱和常数存在显著差异。实验得出，MBR和CAS的K(O,AOB)分别为0.18±0.04和0.79±0.08 g(O2)，以及K(O,NOB)分别为0.13±0.06和0.47±0.04 g(O2) m(-3)（底物仅为NO(2)）。CAS较高的K(0)值归因于传统系统中占主导的大絮体内部的传质效应。相比之下，MBR的污泥由非常小的絮体组成，其扩散阻力可忽略不计。基于这些结果，讨论了活性污泥模型中传质效应的实现，并强调了对MBR运行的影响。
