氯、水混溶器

氯气从氯瓶流出,经加氯机、水射器与水混溶后进入滤后水管道,再流入清水池。尽管池内停留时间保持在0.5～1.2小时,但检查出厂水余氯时,发现水泵与出水干管上所取水样的余氯值有时并不一致,有时出现加氯量大而     

消毒过程中氨氮对氯耗的影响研究

某水厂将地下水与管网水混合作为原水,直接加氯后进入清水池,运行中发现清水池出水中的余氯值变化不规律,有时会出现加氯量越多,出水余氯反而越少的现象.通过静态加氯试验验证了氯耗波动的事实,并与氨氮配水试验作对照,发现原水水样与氨氮配水的加氯曲线存在相似性；通过对折点加氯曲线的分析以及与原水加氯曲线的比较,认为原水加氯符合折点加氯特性,氨氮和管网来水中余氯的变化是造成氯耗不稳的原因.     

芜湖某水厂加氯设施自动化改造

芜湖某水厂以往采用人工方式投加液氯,根据出厂水余氯值反馈预估需要的后加氯量,因此具有很大的延时性和不确定性,出厂水余氯值波动较大,对供水安全影响很大。通过分析当前的加氯现状以及存在的问题,找到了影响出厂水余氯值稳定的主要原因。通过添加中间加氯点和补加氯点,建立了四环加氯控制模型,通过PLC不仅实现了液氯的自动投加,而且实现了将出厂水余氯值稳定在一个较小的波动范围内,保障了供水安全。     

初探出厂水补氯的效果

试验研究了以液氯作为单一消毒剂时,在原水氨氮浓度突升条件下,运用出厂水补充加氯保证出厂余氯及降低总氯耗的影响。试验结果表明,应用出厂水补充加氯时,不仅可以保证出厂水余氯合格、稳定,而且可以大大降低氯的投加量,降低氯耗,进而降低消毒副产物产生的浓度。     

第七水厂氯耗不稳原因分析研究

在生产实践的过程中,常发现开启不同的水源井引起加氯后清水池余氯发生变化,造成加氯量不易控制,针对这种情况开展氯耗不稳定原因分析研究,并对余氯的测定方法进行了比较。     

供水管网中加氯消毒副产物的变化探析

监测了丰水期和枯水期供水管网中余氯和加氯消毒副产物的变化。结果表明,三氯甲烷和加氯消毒副产物的总体和分段变化趋势相似,经过管网输送后三氯甲烷相对出厂水有所增加;管材、使用时间、输送距离会不同程度影响管网中三氯乙醛的浓度;枯水期加氯消毒副产物在出厂水的基础上也会增加。所建立的关系模型显示,监测点加氯消毒副产物与出厂水加氯消毒副产物、管材和输送距离、监测点余氯之间存在良好的线性关系。     

长距离给水管网氯胺消毒的控制研究

以某市第二水源工程供水管网为研究对象,通过测定余氯和茵落总数,考察了氨、氯质量比和出厂水余氯浓度对长距离给水管网氯胺消毒效果的影响。结果表明,在氨、氯质量比为1：4．5时,通过适当提高出厂水余氯浓度,可以有效改善长距离输水管网中的水质,避免增加中途加氯设备,以及便于水厂管理。     

杭州九溪水厂加氯、加氨工艺的改进

介绍了水厂在试运行期间针对滤前水余氯过低，出厂水余氯不稳定而对加氨、加氯工艺所做的改进－滤前水采用氯氨消毒及加药工艺的一些调整。     

常规水处理工艺多点加氯改造

在制水过程中消毒处理有着至关重要的作用,本文介绍通过对九溪水厂加氯消毒方式的改造,采用多点加氯的模式,较好的解决了水厂滤池亚硝化细菌的滋生、出厂水亚硝酸盐超标、出水余氯不稳定的现象,同时降低制水氯耗,减少加氯消毒副产物。     

枯水期出厂水余氯突降原因与对策

针对江门市出厂水在枯水期出现余氯突降的现象,分析了出厂水余氯异常时出厂水及原水水质的变化情况、原水发生微污染时与河流潮汐的关系、原水氨氮和耗氧量的关系、原水氨氮和出厂水余氯的关系。结果表明,出厂水余氯出现突降是由于原水受到微污染造成的;氨氮、耗氧量以及河床水位可以作为原水微污染的预警指标,操作简单、有效;当预测到原水出现微污染时,采取加大和调整前后加氯量的方式,可解决由于原水微污染而引起的出厂水余氯突降的问题。     

Persistence of pharmaceuticals and other organic compounds in chlorinated drinking water as a function of time

Ninety eight pharmaceuticals and other organic compounds (POOCs) that were amended to samples of chlorinated drinking-water were extracted and analyzed 1, 3, 6, 8, and 10 days after amendment to determine whether the total chlorine residual reacted with the amended POOCs in drinking water in a time frame similar to the residence time of drinking water in a water distribution system. Results indicated that if all 98 were present in the finished drinking water from a drinking-water treatment plant using free chlorine at 1.2 mg/L as the distribution system disinfectant residual, 52 POOCs would be present in the drinking water after 10 days at approximately the same concentration as in the newly finished drinking water. Concentrations of 16 POOCs would be reduced by 32% to 92%, and 22 POOCs would react completely with residual chlorine within 24 h. Thus, the presence of free chlorine residual is an effective means for transforming some POOCs during distribution.     

饮用净水管网余氯与细菌总数的相关性研究

通过对饮用净水的出厂水静态水质分析、主干管动态水质分析和配水管网的水质检测,考察了饮用净水管网中余氯与细菌总数之间的相关性.结果表明,饮用净水中的余氯与细菌总数之间呈较为明显的负指数相关,利用两者的量化关系,可通过余氯快速估算出细菌总数,这对提高净水系统水质生物安全性及提高供水水质管理水平具有重要意义.     

西洲水厂投氯系统的技术改造

介绍了西洲水厂将滤后投氯机的控制由单因子反馈控制改造成多因子PLC复合环控制的具体思路及实现方法，改造后保证了在全自动化控制运行时出厂水余氯指标的精确控制和高稳定度。     

串级控制在加氯系统中的应用

分析了人工加氯系统的不足,通过估计流量实现了比值控制;介绍了串级控制结构,建立了过程模型.实际应用结果表明,出厂水余氯稳定,氯耗降低.     

水厂出水加氯消毒的加氯量确定

加氯对控制水厂出水中有害菌群的数量有着至关重要的作用,合理的加氯量对控制水厂出水的菌群含量和水厂成本都有重要的意义。因次氯酸的氧化性强,还可以与水中的一些还原性物质发生反应,因此为了保证一定的余氯,还需要测定还原性物质的耗氯量。一般的还原性物质直接将次氯酸还原为氯化物,而氨氮和次氯酸的反应较特殊,对加氯量的影响也最大。在测定余氯时,采用DPD分光光度法,在测定过程中对国标法做了一些改进,取得了很好的效果。     

Factors influencing the effect of bleached kraft mill effluents on drinking water quality

The taste and odour of drinking waters contaminated with bleached kraft mill effluent (BKME) were investigated. Mill effluents with a wide range of odour thresholds were selected and the effects of biological treatment, conventional water purification, carbon filtration, residual chlorine concentration, and recipient water quality were evaluated. No correlation was found between the original odour of BKME and the drinking water impairment. The taste and odour of drinking water prepared from pure glacial-fed river water to which biotreated BKMEs from three separate pulp mills were added was found to be impaired at effluent concentrations ranging from 0.1 to 0.4%. Effluent biotreatment, conventional water purification, and carbon filtration significantly reduced, but did not completely eliminate, BKME-associated taste and odour in potable water samples. The concentration of residual chlorine in the finished drinking water samples was an important factor influencing the degree of taste impairment.     

Predictive Chlorine Dosing: A New Paradigm

Disinfection by chlorine is common practice in potable water treatment. The most frequently used dose control method is to inject an overdose of chlorine at the inlet to the contact tank and adjust to the desired residual chlorine level in the effluent stream. However, this method of control may not be optimal. The advent of reliable predictions of retention time distributions and the widespread use of programmable logic controllers, coupled with a greater understanding of chlorine disinfection kinetics, offers the potential for more efficient chlorine dosing algorithms. This paper describes one possible algorithm, based on theoretical models, for predictive chlorine dosing.     

Volatile halogenated hydrocarbons in Belgian drinking waters

A comparative study was carried out to determine levels of volatile halogenated hydrocarbons, especially trihalomethanes (THM) in different Belgian drinking waters, prepared from both ground and surface waters. In addition to examining raw and treated water leaving the production plants, changes in haloform concentration during transport in the distribution system were also studied. Only a slight decrease of haloform concentration after decompression in water towers and reservoirs occurred and was rapidly compensated by on going chlorination by residual free chlorine.Despite of the very different conditions used for chlorination in the plants studied, a fairly clear relation was found between total THM content in the finished waters and TOC-values of the raw waters, indicating that the primary organic load was the determining factor for haloform formation.