Department of Chemical Engineering and Applied Chemistry, University of Toronto, ON, Canada.
Appl Microbiol Biotechnol. 2010 Nov;88(5):1205-14. doi: 10.1007/s00253-010-2829-3. Epub 2010 Aug 25.
Problems with deflocculation and solids separation in biological wastewater treatment systems are linked to fluctuations in physicochemical conditions. This study examined the composition of activated sludge bacterial communities in lab-scale sequencing batch reactors treating bleached kraft mill effluent, under transient temperature conditions (30 to 45 °C) and their correlation to sludge settleability problems. The bacterial community composition of settled and planktonic biomass samples in the reactors was monitored via denaturing gradient gel electrophoresis of 16S ribosomal RNA gene fragments. Our analysis showed that settled biomass has a different community composition from the planktonic biomass (49 ± 7% difference based on Jaccard similarity coefficients; p < 0.01). During times of poor sludge compression, the settled and planktonic biomass became more similar. This observation supports the hypothesis that settling problems observed were due to deflocculation of normally settling flocs rather than the outgrowth of non-settling bacterial species.
生物污水处理系统中脱稳和固液分离问题与理化条件的波动有关。本研究考察了在实验室规模序批式反应器中处理漂白硫酸盐浆厂废水时，活性污泥细菌群落的组成，该反应器在温度瞬变条件（30 至 45°C）下运行，并与污泥沉降性能问题相关联。通过变性梯度凝胶电泳（DGGE）分析 16S rRNA 基因片段，监测了反应器中沉降和浮游生物量样本的细菌群落组成。我们的分析表明，沉降生物量与浮游生物量的群落组成不同（基于 Jaccard 相似系数，相差 49±7%；p<0.01）。在污泥压缩性能差的时期，沉降和浮游生物量变得更加相似。这一观察结果支持这样的假设，即观察到的沉降问题是由于正常沉降絮体的脱稳，而不是不沉降细菌物种的过度生长。
