A^2/O工艺中好氧污泥絮体的分形结构与理化特征分析  

Fractal Structure and Physicochemical Characteristics Analysis of Aerobic Sludge Floc in A^2/O Process

作　　者：宣科佳[1] 王毅力[1] 魏科技[1] 杜接弟[1] 张桐[1] 

机构地区：[1]北京林业大学环境科学与工程学院,省部共建森林培育与保护教育部重点实验室,北京100083

出　　处：《环境科学》2009年第7期2013-2021,共9页Environmental Science

基　　金：国家自然科学基金项目(50578012;20407004);国家高技术研究发展计划(863)项目(2007AA06Z301);教育部新世纪优秀人才计划项目(NCET-06-0120);霍英东青年教师基金项目(91078);北京市科技新星计划A项目(2006);北京市教委项目;北京市重点学科项目(XK100220555)

摘　　要：采用图像法和沉降柱法分别研究了A2/O工艺中好氧污泥絮体的形貌、粒度分布、低维分形维数和沉降速率、有效密度、空隙率以及质量分形维数,并尝试探讨了上述相关性质与这些污泥宏观操作性质(沉降、压缩、脱水和稳定性)相关的各种理化指标以及胞外高分子物质(EPS)的含量之间的变化关系.结果表明,污泥絮体呈现不规则的形貌,表面具有空隙.其有效密度一般随着其粒径的增加而降低,而空隙率和沉降速率却呈现与有效密度相反的变化趋势,这些均表明了污泥絮体的分形结构的存在.2次所采集的污泥絮体的中位直径分别为248.81、332.86μm,有效密度的平均值分别为0.0040、0.0072g·cm-3,自由沉降速率的平均值分别为2.67、4.79mm·s-1,空隙率的平均值分别为0.94、0.89,一维分形维数分别为1.03、1.19,二维分形维数分别为1.64、1.84,采用基于Logan经验公式的有效密度-最大直径的双对数关系确定的质量分形维数分别为1.74、2.29.尽管第2次所采集的污泥絮体较为密实,但其表面粗糙程度却比第1次的低.此外,研究中发现絮凝能力较高或负电荷较高的A2/O好氧污泥絮体具有高的SVI和ZSV值;分形维数较低的污泥具有高的剪切敏感性和低絮体强度,相应的污泥稳定性低;EPS总量高的污泥脱水性能差,EPS中蛋白质含量高的污泥其表面电荷也较高.Image analysis method, free settling test were performed to determine the morphology, particle size distribution, free setting velocity, effective density, porosity and fractal dimensions in different topological spaces of aerobic sludge flocs in A2/O process. Then the physicochemical indices, corresponding to the sludge properties such as： settleability, compressibility, dewaterability and stability, were measured. Besides these, the extra-cellular polymeric substances （EPS） were extracted from sludge and classified as different components. The results showed that the sludge floc with irregular morphology was high porous. The effective densities of these sludge flocs generally increased with the increase of their size, but the porosities within the flocs and their free settling velocities decreased accordingly. The median diameters of the sludge flocs at two different sampling times were 248.81 μm, 332.86 μm, respectively. Their corresponding average effective densities were 0.004 0, 0.007 2 g·cm^-3, and average free settling velocities were 2.67 mm·s^-1, 4.79 mm·s^-1, and giving the average porosities of 0.94, 0.89. The dimensional analysis methods, based on power law correlations between floc perimeter, projected area and maximum length, were used to determine the one- and two-dimensional fractal dimensions （D1 and D2 ） of sludge flocs, giving D1 = 1.03 or 1.19, D2 = 1.64 or 1.84. The mass fractal dimensions （Dr） of these sludge flocs were determined by the bi-logarithm relations of effective density （based on Logan empirical equation）-maximum diameter which equaled to 1.74 or 2.29. The above results demonstrated that the second sample of sludge flocs was larger and more compact, but smoother than the first sample. Moreover, the results also showed that the sludge flocs in A^2/O process with high flocculating ability or high negative surface charge had high values of sludge volume index （SVI） and zone setting velocity （ZSV）, and low values of fractal dimensions in 2-D or 3-D spac

关 键 词：好氧污泥絮体 图像分析 沉降速率 分形结构 理化特性 活性污泥特征 

分 类 号：X505[环境科学与工程—环境工程]