| 活性污泥絮体粒径分布与分形维数的影响因素 |
| 摘要点击 2235 全文点击 1707 投稿时间：2013-01-08 修订日期：2013-03-12 |
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| 中文关键词 活性污泥 絮体 粒径分布 分形维数 速度梯度 EPS |
| 英文关键词 activated sludge floc floc size distribution(FSD) fractal dimension velocity gradient EPS |
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| 中文摘要 |
| 絮体粒径分布和分形维数是活性污泥的重要参数. 应用激光粒度仪测量了好氧活性污泥絮体在絮凝过程的粒径分布,研究了速度梯度、VSS/SS、EPS含量及Zeta电位对絮体粒径分布的影响. 结果表明,絮体平均粒径与速度梯度显著负相关(R2>0.80),与Kolmogorov尺度数量级基本相当,其间差异性与污泥VSS/SS、絮体强度等有关; 相同的速度梯度下,絮体平均粒径与VSS/SS或EPS含量显著正相关(R2>0.85),与Zeta电位负相关. 有机质和EPS在活性污泥絮凝中作用明显,会增强絮体强度,提升絮凝效果; EPS中蛋白质比多糖对絮凝的促进作用更明显. 基于显微图像分析方法,得到了好氧活性污泥絮体二维分形维数为1.28~1.72,三维分形维数为1.70~2.69.絮体分形维数随VSS/SS或EPS含量的增加而减小; 对于相同的活性污泥,絮体三维分形维数随粒径增大而减小,符合幂函数关系式. |
| 英文摘要 |
| Floc size distribution (FSD) and fractal dimension are the important parameters for activated sludge. FSD of aerobic activated sludge during flocculation process was measured by a laser particle size analyzer, and the influence of velocity gradient, VSS/SS, EPS content and Zeta potential on FSD was investigated. The results showed that the floc volume-average size was negatively correlated to velocity gradient (R2>0.80), and the order-of-magnitude of the floc volume-average size was equivalent to that of Kolmogorov scale (their differences were dependent on sludge VSS/SS, floc strength and etc). At a fixing velocity gradient, the floc volume-average size was positively correlated to VSS/SS or EPS (R2>0.85), whereas negatively correlated to Zeta potential. Organic matter and EPS played important roles on the flocculation of activated sludge by enhancing the floc strength and improving the flocculation effect. Compared with polysaccharides, proteins in EPS seemed to be more beneficial for the flocculation of activated sludge. Based on microscopy and image analysis, the 2D and 3D fractal dimension of aerobic activated sludge floc was determined to be 1.28-1.72 and 1.70-2.69, respectively. It was found that fractal dimension (2D and 3D)was decreased with increasing VSS/SS (or EPS content). For the same activated sludge, the 3D fractal dimension was decreased with increasing floc size, and the relationship between 3D fractal dimension and floc size could be approximately described by a power function. |
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