上向流过滤应用技术研究

【作者】 谢社平；

【导师】 余健；

【作者基本信息】 湖南大学 ， 市政工程， 2001， 硕士

【摘要】 上向流过滤是一种理想的过滤方式。与传统快滤池相比具有滤层截污量大，水头损失小，过滤周期长等特点。但它有滤速提高时滤层易膨胀，滤层反冲洗不易干净的问题。 本课题在总结前人经验的基础上，经过模型试验，对该种滤池的过滤及反冲洗进行了深入的研究。通过与均质滤料滤池、传统快滤池的过滤对比试验，对上向流过滤的滤层厚度及滤料级配、承托层厚度及级配进行了优化；讨论了滤料最小粒径与过滤极限水头损失的确定；探讨了滤层厚度与滤料当量粒径之比值l/d_e对上向流过滤性能的影响；研究了滤层截污规律与水头损失变化规律，滤后水浊度变化规律；提出了滤料流失的防止措施，解决了上向流过滤提高滤速上层细滤料易流化的问题；第一次把气水反冲洗技术用于上向流过滤，通过正交实验得出了气水反冲洗最佳参数，通过对比试验检验了气水反冲洗效果，成功地解决了上向流过滤反冲洗不易干净的问题。更多还原

【Abstract】 Compared with conventionally rapid filter, upflow filtration is a more sensible filter method, which is characterized by large capacity for storage of solids, small head loss and long filter run. The main disadvantages of upflow filtration appear to be (a) the tendency for the expansion of the media because of increasing flow rates, (b) the difficulty of backwashing if layers of deposit accumulate at certain depths of the media.On the basis of former experience, further study about upflow filtration and have air-water backwashing have been conducted through pilot-plant test. In this article. optimum of the depth and grain size of the media is achieved. At the same time, the minimal grain size of the media and available head loss are also determined. In addition, the influence on the function of the upflow filtration caused by change of l/de ratio (in which 1 is the bed depth and de is the geometric mean size of the media) is discussed. Furthermore, the regularity of impurities removal, head loss of the filter and the variation of effluent turbidity have been studied. To solve the problem in upflow filtration that the fine grains at the top of medium are apt to be fluidized when the filtration rate is increased, feasible advices are proposed in this article. During the test. air-water backwashing is applied to upflow filtration for the first time. The best parameters of air-water backwashing are obtained through orthogonal tests, meanwhile, the most satisfying effect of air-water backwashing is decided by comparison. Thus, the difficulties in backwashing of upflow can be overcome successfully.更多还原