【作者】 李彦；

【导师】 金奇庭； 王东升；

【作者基本信息】 西安建筑科技大学 ， 环境工程， 2004， 硕士

【摘要】 在城市用水和废水处理工艺中，混凝过程(混合、凝聚、絮凝)是应用最普遍的单元操作工艺技术，可作为沉淀、气浮、过滤等工艺流程的前置工艺技术环节。絮凝效果的好坏往往决定着后续流程的运行工况、出水质量和成本费用，它始终是水处理工程中重要的研究开发领域，其中絮凝剂是絮凝技术应用的关键。聚合氯化铝(PAC)是当前工业生产技术最成熟、应用最广泛的无机高分子絮凝剂(Inorganic polymer flocculants，IPF)，因此对PAC混凝过程的深入研究有着重要的意义。 本课题以水中腐殖酸有机物和高岭土胶体颗粒为去除对象，采用静态显微图像法和环流气浮反应器(ES-DAF)研究了聚合氯化铝混凝絮体的分形结构和气浮去除特性。实验结果表明：在本实验的各种条件下，絮体的分形维数都在1～2之间，且数据点的相关性很好，说明了混凝沉淀絮体的形成具有“分形”特征。以卷扫絮凝为主要混凝机理时，形成的絮体趋向于多分枝的松散结构，分形维数低。絮体的长短比大约80％分布在1.2～2.5之间，证明了絮体的形状是极不规则的。与实验室配水的絮体分形值相比，湖水中的絮体分形值较低，从1.0314—1.4600。pH值、污染物种类和聚合铝形态以及混凝机理对絮体的密实性、规整性和絮体分形维数有很大的影响。采用环流气浮反应器去除腐殖酸和高岭土混合物，达最高去除率的投药量要比分别去除腐殖酸和高岭土时大，但去除效果更好。实验中选用的大港工业聚合铝对腐殖酸和高岭土的去除率达70％左右，比实验制备的聚合铝有更好的混凝气浮去除效果，且其受溶液pH条件的影响也较小。气泡粒径与Zeta电位使聚合铝混凝吸附污染物表现出与混凝沉淀中不同的现象。同时，pH值、污染物种类和聚合铝形态也会对聚合铝的气浮去除特性产生影响。更多还原

【Abstract】 In the treatment process of domestic water and waste water, coagulation process (mixing,agglomeration,flocculation) is the most popular unit operation, used as pre-process of precipitation,flotation ,filteration and so on.the effect of flocculation decides the condition of operation, the quality of effulent and the cost. It is important research branch in the treatment of water and waste water, and flocculant is the key in application of flocculation technology. Polyaluminum chloride is one of the mature and popular inorganic polymer flocculants, so the deep study on the coagulation process have significance.The humic acid and the kaolin are removal object in this paper. Image analysis and a novel ES dissolved air flotation reactor(ES-DAF) are used in the study on fractal structure of alum floe and removal characteristics by flotation. The results of the experiment show that in varies conditions the fractal dimention of floe is between one and two. The correlation of the experiment data is good, which illustrates fractal characteristic of floe. When sweep flocculation acts as the main mechanism, floe tend to forming branch structure and have lower fractal dimention. The distributions of Elongation ratio show that the majority of the particles, approximately 80%, possessed ratios in the range between 1.2 and 2.5, which proves the irregular shape of floe. The fractal dimention of floe in Lake contrasting with man-made waste water’s, are lower. The value is from 1.0314 to 1.4600. The type of pollutants, pH, form of PAC and coagulation mechanism have important influence on the density, regulation and fractal dimention of floe. The floccution of removal the humic acid and the kaolin by ES-DAF has better removal effect than the removal organic or clay respectively. But the quantity of flocculants is more. The industry PAC has high turbidity and organic removal. The removal efficiency is about 70% higher than the PAC made in lab, and is affected little. Contrast to coagulation precipitation, flotation exhibit the different phenomenon because of the size of bubble and Zeta potentials. At the same time, the type of pollutants, pH, form of PAC and coagulation mechanism have important influence on the removal characteristics in flotation..更多还原