【作者】 王姣；

【导师】 范跃华；

【作者基本信息】 华中科技大学 ， 市政工程， 2006， 硕士

【摘要】 建设部于2005年颁布了《城市供水水质标准》(CJ/T206-2005),与以前的国家标准相比,对水质提出了更高的要求:其检测项目由35项增加到101项,浊度标准为1NTU,还提出了有机物指标及农药控制指标等。对于以上水质要求,在我国的大城市目前基本可达到,但相当多的中小城镇水厂的出厂水水质已经不能满足新标准要求。滤池作为现有水厂常规净水工艺流程中的最重要的处理单元,其技术改造必然是工作重点,反冲洗设备的改进又是重中之重,因为其工作性能的优劣直接关系到滤池是否能正常工作。本研究针对中小城镇水厂常用滤池的反冲洗系统中的冲洗排水设备及配气配水设备两部分进行创新性研究。新的反冲洗排水设备在吸收新型翻板滤池冲洗排水理念的基础上设计了一种更加符合滤料沉降规律的排水浮阀。由于公认滤池的冲洗效果以气水反冲洗方式最佳,故本研究的配气配水设备将结合目前国内水厂使用较多的双阀滤池和普通虹吸滤池两种池型,吸取V型滤池及翻板滤池中冲洗气垫层的形成原理,采用特定开孔形式的丰形管系结构,以求配气配水均匀,并且使得老滤池的改造较为简便易行。本文从理论上推导出新的排水浮阀设备排水能力的计算式,并用模型试验的大量数据对理论公式进行验证和修正,为实际滤池的技术改造工程设计提供了重要的技术依据。对新的配气配水设备分别进行了单独水洗、单独气洗及气水同时冲洗三种方式下的模型试验。试验结论表明:单独水洗时配水均匀性要满足滤池冲洗要求,开孔率必须小于0.466%,而且均匀性在开孔率较小时主要受开孔率大小影响;单独气洗时,配气孔孔径对均匀性影响不大,而且开孔率及冲洗强度对均匀性的影响比单独水洗时要小;气水同时反冲洗时,配气配水均匀性随开孔率增大而减小,随气垫层高度增加而提高。另外,在气水反冲洗时,维持稳定气垫层的水流速度及空气流速分别为0.4m/s和2.05m/s。在中小城镇水厂原有旧滤池池型改建为气水反冲洗滤池的工程中,以上技术参数具有重要的参考价值。更多还原

【Abstract】 The construction bureau has issued Water Quality Standards for Urban Water Quality in the year of 2005, Comparing to the formal national standard, it refers to a more strictly water quality: The number of checked item has increased to 101 from 35, the turbidity standard has been changed to 1 NTU, and it adds organism index and pesticide control index and so on.In the big cities of our Country it could reach above water quality standards, but to a number of middle and small towns, the supply water can’t accord with the new standard.The filter, as the most important unit of the normal water treated techniques flow for modern water supply plant, its technique reform is certainly very important, whereas the backwashing facility’s improvement is the key point, because its work performance impacts directly on the filter’s work..We carried out the innovation research to the washing device and gas and water supply facility of backwashing system for normal filter in the middle and small towns in this paper.On the base of absorbing in the new washing abstract of shutter filter, the new backwashing facility adopts a float-valve which is more suitable to the subsiding law of filter material. It is well known that backwashing with gas and water could get best result for filter washing. So the gas and water supply system in this paper will combine the pool type of two-valves filter and normal siphon filter which are used frequently in our country, absorb in the forming principle of washing gas-cushion layer in the V-filter and shutter filter, adopt cross-pipe structure for special open formation.We educe out a new formula for calculating drainage capability of the new float-valve facility from the theory and have it checked and modified by using much data from model experiments. It carries out water washing, gas washing and washing with both water and gas. these three kinds experiments to the facility for water and gas supple respectively. The result is as following: when only washing with water, the uniformity of water supply should satisfy the filter washing requirement, open area ratio must less than 0.466% and when it is small it mainly affects the uniformity. When only washing with gas, the diameter gas supply open has little influence on uniformity, and its open area ratio and washing intensity also have less influent than washing only with water. When washing with gas and water, the uniformity of water and gas supply will decrease as open area ratio being increased and will raise as the height of gas cushion layer being increased. Additionally, during the washing with gas and water, the flow rate of water and gas for holding stable gas cushion is 0.40m/s and 2.05m/s respectively. In the project for changing the old filter to the new one with both water and gas washing in the middle and small towns, the above technique parameter have important reference value.更多还原