Kaewpipat K, Grady C P L
L. G. Rich Environmental Research Laboratory, Clemson University, SC 29634-0919, USA.
Water Sci Technol. 2002;46(1-2):19-27.
As a first step in understanding nonlinear dynamics in activated sludge systems, two laboratory-scale sequencing batch reactors were operated under identical conditions and changes in their microbial communities were followed through microscopic examination, macroscopic observation, and denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rRNA gene segments from the prokaryotic community. Two experiments were performed. The first used activated sludge from a local wastewater treatment plant to start the replicate reactors. The second used the biomass from the first experiment as a source by intermixing the two and equally redistributing the biomass into the two replicate reactors. For both experiments, the two reactors behaved fairly similarly and had similar microbial communities for a period of 60 days following start-up. Beyond that, the microbial communities in the two reactors in the first experiment diverged in composition, while those in the second experiment remained fairly similar. This suggests that the degree of change occurring in replicate reactors depends upon the severity of perturbation to which they are exposed. The DGGE data showed that the bacterial communities in both experiments were highly dynamic, even though the system performance of the replicate reactors were very similar, suggesting that dynamics within the prokaryotic community is not necessarily reflected in system performance. Moreover, a significant finding from this study is that replicate activated sludge systems are not identical, although they can be very similar if started appropriately.
作为理解活性污泥系统中非线性动力学的第一步，在相同条件下运行了两个实验室规模的序批式反应器，并通过显微镜检查、宏观观察以及对原核生物群落中PCR扩增的16S rRNA基因片段进行变性梯度凝胶电泳（DGGE），跟踪其微生物群落的变化。进行了两项实验。第一项实验使用当地污水处理厂的活性污泥启动重复反应器。第二项实验将第一项实验中的生物质作为来源，将两者混合并将生物质平均重新分配到两个重复反应器中。对于这两项实验，两个反应器在启动后的60天内表现相当相似，并且具有相似的微生物群落。在此之后，第一项实验中两个反应器的微生物群落组成出现分歧，而第二项实验中的微生物群落仍然相当相似。这表明重复反应器中发生的变化程度取决于它们所受到的扰动的严重程度。DGGE数据表明，尽管重复反应器的系统性能非常相似，但两项实验中的细菌群落都具有高度动态性，这表明原核生物群落内部的动态不一定反映在系统性能中。此外，这项研究的一个重要发现是，重复的活性污泥系统并不完全相同，尽管如果启动得当它们可能非常相似。
