The inside story of water-treatment processes
The inside story of water-treatment processes
复制标题
水处理过程的内幕
DOI：
10.1061/(asce)0733-9372(1995)121:12(846
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发表时间：
1995
影响因子：
2.2
通讯作者：
K. Ives
中科院分区：
文献类型：
--
作者：
K. Ives
水处理过程可以被看作是一系列的黑盒子，脏水进入，干净的水流出。这种混凝、絮凝、澄清、过滤和浮选工艺的方法可能会产生令人满意的设计，但通过深入了解这些工艺单元的内部工作，可以实现更合理的优化。自1957年以来，伦敦大学学院的研究人员一直在窥视这些过程的“黑匣子”，以了解其详细工作的内幕。最早的这些使用放射性标记的单细胞藻类，以便当通过沙子过滤时，可以检测过滤器内的详细沉积模式，而不会干扰该过程。后来，在全尺寸漏斗形池（正常的英国）中进行了絮凝层澄清的研究。当时的设计）用锂示踪剂测量三维流动模式。这证明了平底澄清池的优势，这是现在一个常见的设计开发。最近，视频内窥镜的使用允许直接观察和记录过滤器孔隙内的沉积，因为它动态发生，而不需要提取样品。同样的技术，但使用高速录像，已被应用于过滤器清洗，显示空气-水反冲洗的优势，采用“脉冲脉冲”模式的加强清洗。这些最新的技术正在应用于溶气浮选中的气泡形成，以检查减压点处的空气释放和絮凝物附着的细节。
Water-treatment processes can be regarded as a series of black boxes, with dirty water in and cleaner water out. This approach to coagulation, flocculation, clarification, filtration, and flotation processes may result in satisfactory design, but more rational optimization can be achieved with insight into the internal workings of these process units. Since 1957, University College London researchers have been peering into the “black boxes” of these processes in order to learn the inside story of their detailed workings. The earliest of these used radioactively labeled unicellular algae, so that when filtered through sand, their detailed deposition pattern within the filter could be detected without interfering with the process. Later, studies on floc blanket clarification in a full-size hopper-shaped tank (the normal U.K. design at that time) measured the three-dimensional flow pattern with a lithium tracer. This demonstrated the advantage of flat-bottomed clarifiers, which is now a common design development. Recently, the use of video-endoscopy has allowed direct observation and recording of deposition within filter pores as it occurs dynamically, without the need of extract samples. The same technique, but using high-speed videorecording, has been applied to filter washing, showing the advantage of air-water backwashing, employing the “collapse-pulsing” mode of enhanced cleaning. These latest techniques are being applied to bubble formation in dissolved-air flotation to examine the details of release of air and floc attachment at the depressurization point.