饮用水处理工艺中消毒副产物的变化特征研究

为阐明饮用水厂运行中主要消毒副产物的形成特征及转化规律,提出有效的控制措施,以北方某饮用水厂为研究对象,对采用预加氯的不同处理单元出水中3类消毒副产物,即8种卤乙酸(HAAs)、亚硝基二甲胺(NDMA)和4种三卤甲烷(THMs)的变化特征进行了研究。结果表明,经预氯化后3类副产物显著增加,HAAs、NDMA和THMs和质量浓度合计分别为33.1μg/L、9.0 ng/L和55.1μg/L;经双层滤料过滤后得到不同程度去除,5种可去除HAAs的去除率为15.7%～60.8%,NDMA去除率为48.1%,4种THMs的去除率为26.1%～49.2%。氯胺消毒下总出水中3类副产物含量也未明显增加,表明预氯化及氯胺消毒是进一步削减消毒副产物产生、降低饮用水健康安全风险的重要控制措施。     

共存离子对饮用水中5种卤乙酸生成的影响

以腐殖酸作为天然水体中消毒副产物(DBPs)前体物,模拟了饮用水消毒过程。研究了水体中共存金属离子Ca2+、Mg2+、Cu2+、Al3+、Zn2+、Fe3+、Fe2+和非金属离子NH4+、As3+、F-等对饮用水氯消毒过程中5种卤乙酸(HAAs)包括一氯乙酸(MCAA)、一溴乙酸(MBAA),二氯乙酸(DCAA),三氯乙酸(TCAA)、二溴乙酸(DBAA)和总HAAs生成量的影响。结果表明,以上离子对5种HAAs和总HAAs生成量和含量分布均产生影响,但影响程度有所不同。除了水中F-在研究含量范围内对HAAs的生成影响不明显以外,Ca2+、Mg2+、Cu2+、NH4+、As3+等离子对HAAs总体上产生抑制作用,而Al3+、Zn2+、Fe3+、Fe2+等离子对HAAs的生成总体有促进作用。     

氯胺消毒对管网中消毒副产物的控制

相对氯消毒，氯胺具有消毒副产物生成量低的特点。本试验模拟管网，取典型的停留时间2d，考察了氯胺消毒时，pH和C12：N对管网中的消毒副产物（三卤甲烷和卤乙酸）浓度的影响。试验表明，消毒副产物的浓度及其含溴的程度基本上随着pH降低、C12：N升高而增大。试验条件下，氯胺生成的卤乙酸量大都高于三卤甲烷，并且以二卤乙酸为主，这和自由氯时所生成三卤甲烷多、卤乙酸以三卤乙酸为主的倾向正好相反。     

管道分质供水TCCA消毒方法

对三氯异氰尿酸(TCCA)消毒法在管道分质供水中的应用进行了研究。结果表明,利用TCCA消毒管道分质供水,只要控制管网水中余氯质量分数>3.0×10-8,就能起到良好的消毒效果,并能有效的控制消毒副产物,使管道分质供水具有较好的口感。采用的TCCA消毒法在管道分质供水工程具有广泛应用前景。     

二氧化氯与氯分步联合消毒减少饮水中亚氯酸盐的研究

二氧化氯和氯可以与水中有机物反应生成亚氯酸盐(CIO^-2)和三卤甲烷(THMs)和三卤乙酸(HAAs)等对人体有害的有机副产物。本研究采用二氧化氯和氯分步联合投加消毒武汉汉江水源水，结果表明，分步投加二氧化氯和氯的间隔时间约为30min，水样的pH为6时，联合消毒后水中CIO^-2的含量随着加氯量的增加逐渐减少，CIO^-2反应生成CIO^-2的转化率逐渐增高。     

微污染水库原水的消毒副产物控制

上海市南汇自来水厂从青草沙水库取水,原水加氯后在输送途中反应生成的消毒副产物(DBPs)使得原有处理技术和工艺难以达到上海市的新版地方标准DB31/T 1091—2018,为此,需要进行研究改进DBPs的控制方法和工艺。试验以水厂原水为研究对象,分析活性炭的吸附、多点加氯等工艺对消毒副产物生成的影响,同时研究了温度与消毒副产物产生的关系。研究发现,投加粉末活性炭15~20 mg/L后,三卤甲烷(THMs)的控制效果明显,即使加氯量达到3 mg/L,THMs也不超过0.15mg/L。多点加氯可以有效降低前期加氯造成的消毒副产物生成量,水温升高使得余氯量明显降低,从而影响消毒副产物的生成量。消毒后的水样中三氯甲烷浓度约为其他组分的一倍,控制三氯甲烷的生成是控制THMs的关键。本研究推荐采用添加粉末活性炭、控制水温夏天方法来削减南汇自来水厂出水中THMs的总量,研究也为自来水厂消毒副产物的控制提供了实操性的建议和技术依据。     

顺序投加联合消毒剂二氧化氯-氯胺对饮用水中消毒副产物的控制

传统氯消毒工艺因易生成对人体有害的消毒副产物被广泛关注,采用替代氯消毒工艺控制消毒副产物是目前的研究重点。该文以天津市某自来水厂滤后水为试验对象,采用二氧化氯-氯胺顺序投加联合消毒工艺,分析了不同投加量组合对消毒副产物(THMs,HAAs和亚氯酸盐)产量的控制情况。结果表明当二氧化氯投加量为0.10~0.50 mg/L、氯胺投加量为0.50~1.50 mg/L时,消毒副产物的生成量均能得到有效控制,符合相关标准的要求。     

烹饪过程中氯代溴代碘代类三卤甲烷生成的影响因素

饮用水消毒过程中产生的THMs在一定条件下会对人体产生致癌、致畸、致突变性,其中I-THMs的毒性要远大于BrTHMs和Cl-THMs。通过模拟烹饪过程,评估日常饮食THMs暴露风险,主要研究加热温度、食盐浓度以及余氯量对日常烹饪过程中THMs生成的影响。研究结果表明:I-THMs、THMs(Cl/Br-THMs)均随余氯的增加而增加;I-THMs随食盐浓度的增加而增加,THMs(Cl/Br-THMs)随食盐浓度的增加而减少;I-THMs随加热温度增加而降低,THMs(Cl/Br-THMs)随温度先增加后降低,峰值在65℃。营养物质的加入会增加I-THMs和THMs(Cl/Br-THMs)的生成。含KIO_3的食盐比含KI的食盐生成的消毒副产物少,应严格控制食盐的加入量和种类。建议烹饪过程应尽量在高温敞开系统进行,同时严格把关用户端的余氯量,从而减少消毒副产物的生成。     

城市供水管网消毒副产物及多级加氯消毒

城市供水过程中,消毒副产物产生受到消毒剂种类、投加量、水源中有机物、温度、反应时间等因素的影响;在管壁、生物膜的作用下,消毒副产物会在市政管网中发生迁移和转化。多级加氯能够缓解出厂水消毒压力,合理布局一级消毒、中途泵站二级消毒以及终端消毒,可将消毒副产物产生的影响控制至最低,改善管网整体水质。     

氯胺消毒工艺在郊区水厂的应用实践

该文介绍了上海浦东新区南汇地区郊区水厂的原水具有高耗氧量、高氨氮、季节性变化大的特点。通过在自来水制水工艺中增添加氨装置,控制沉淀池出水氨氮为0.5 mg/L左右;采用化合氯消毒后,可有效保证管网余氯稳定性和控制消毒副产物,但该方法也存在菌落总数检出率和色度升高及制水成本提高约0.008元/t的问题。     

高铁酸盐控制饮用水中消毒副产物的研究进展

消毒是饮用水处理中特别重要的一步。随着工农业经济的飞速发展,水源中检测出大量种类复杂的有机污染物质,在消毒过程中这些有机物与消毒剂反应会产生一些对人体健康具有潜在危害的消毒副产物(DBPs),例如三卤甲烷、亚氯酸盐、溴酸盐等。因此,能否有效控制DBPs的产生成为了评价饮用水消毒质量效果的一项重要指标,而去除消毒副产物前体物是控制DBPs产生的关键。高铁酸盐作为一种绿色高效的新型水处理剂,具有强氧化还原能力,处理后的水中基本不会产生DBPs且能有效地抑制一些常见DBPs。文中综述常见的DBPs及前体物的种类、DBPs控制方法以及高铁酸盐在饮用水处理中对DBPs的控制。     

饮用水处理中氯化消毒副产物三卤甲烷和卤代乙酸研究进展

三卤甲烷和卤代乙酸是饮用水氯化消毒的典型副产物。该文结合国内外学者对三卤甲烷和卤代乙酸的研究成果对这两类物质的形成的影响因素、主要检测方法及控制方法进行了总结。     

饮用水中典型氯化消毒副产物生成模型的研究进展

对自由氯及氯胺消毒技术产生的典型卤代消毒副产物三卤甲烷和卤乙酸生成机理与模型进行了综述,并同时对其它消毒副产物3-氯-4(二氯甲基)-5-羟基-2(5H)-呋喃酮(MX)以及二甲基亚硝胺(NDMA)的生成速率和影响因素做了详细介绍。探索消毒副产物的产生与常规水质指标间的关系,建立与之对应的生成模型,可有效指导水厂工艺的运行,从而有效降低消毒副产物在出厂水中的含量。     

Chlorination by-products in surface water treatment process

Chlorine disinfection is carried out for the purpose of sterilization of microbes existing in drinking water. Chlorination may cause the formation of disinfection by-products (DBPs) by the reaction of free chlorine with humic substance in the water. In particular, the DBPs including trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), and haloketones exist in tap water. The US Environmental Protection Agency (US EPA) suggests 80 μg/L THMs and 60 μg/L HAAs as maximum contamination levels for drinking water. This study was performed to detect the level of DBPs in drinking water and to measure disinfection by-product formation potential (DBPFP) of raw water with four different properties. After 24 h of chlorination, the measured level of trihalomethane formation potential (THMFP), haloacetic acid formation potential, and haloacetonitrile formation potential ranged from 55.0 to 102.6 μg/L, from 9.1 to 23.6 μg/L, and from 10.3 to 33.6 μg/L, respectively. DBPFP was the highest at pH 7.0 and increased with the reaction time. Among the DBPFP, THMFP was detected more frequently than the others. In the treated water, DBPs were measured with a mean value of 47.0 μg/L. Chloroform, dichloroacetic acid, trichloroacetic acid, and dichloronitrile all known as hazardous compounds, were measured as major parts of DBPs.     

Effectiveness of Bio-Activated Carbon Filtration and Ozonation on Control of Halo Acetic Acids Formation during Chlorination of Ganga River Water at Kanpur,India

ABSTRACT

Chlorinated water from River Ganga is the main source of drinking water in Kanpur, India. But, this water contains a significant amount of disinfection by-products (DBPs) that include haloacetic acids (HAAs) as a major contributor, which pose a carcinogenic risk on long-term ingestion. Therefore, in order to control HAAs formation, different combinations of ozonation and bio-activated carbon filtration (BAC-filtration) were studied. The results elucidate that slight ozonation followed by BAC-filtration proved effective in reducing (75.8%) HAAs formation and meet the USEPA drinking standards. These findings open a path to explore cost-effective treatment techniques in continuous mode for safe drinking water.     

液氯和次氯酸钠对饮用水消毒效果的生产性试验研究

以次氯酸钠代替液氯消毒是未来饮用水消毒的重要发展方向,但对于次氯酸钠消毒对供水水质的影响一直缺乏生产性试验研究.以上海2个净水厂实际生产工艺考察了液氯和次氯酸钠2种消毒剂的消毒效果,对于其在微生物消毒效果、消毒副产物生成和对氮磷及有机物去除方面进行了比较分析.研究发现,2种消毒方式对微生物的杀菌效率基本相同,但是次氯酸...     

世界六大城市自来水水质比较

从感官性状和一般化学指标、毒理学指标和消毒副产物等三个方面对世界六个城市的自来水水质情况进行了比较，结果表明上海市自来水在色度、铁、锰、pH、铝、氯化物、氨氮、耗氧量、总有机碳TOC、余氯、消毒副产物THMs等水质参数方面，明显劣于其他城市。上海市自来水急需深度处理工艺改善水质。     

Effect of Ozonation on Trihalomethane and Haloacetic Acid Formation and Speciation in a Full-Scale Distribution System

Disinfection by-product (DBP) formation was evaluated before and after ozone implementation at two full-scale drinking water facilities in Las Vegas, NV USA. The two treatment plants used preozonation for primary disinfection followed by direct filtration with subsequent chlorination for secondary disinfection. DBP data was evaluated from the finished water of the two treatment plants along with six locations in the distribution system. Results showed that preozonation reduced the formation of total trihalomethanes (TTHM) by up to 10 μg/L and the sum of five haloacetic acids (HAA5) by up to 5 g/L. These reductions were primarily due to decreases in the di- and trichlorinated DBPs such as chloroform, bromodichloromethane, and trichloroacetic acid. Ozonation appeared to shift the speciation of TTHMs and HAA5 to favor increased formation of the di- and tribrominated species such as bromoform, chlorodibromomethane, and dibromoacteic acid. A bromide mass balance showed that <30% of the raw water bromide was accounted for by the formation of TTHMs (8–21%), HAAs (2–3%) and bromate (5%). Reducing the concentration of THMs and HAAs is often not the primary purpose of ozonation, but it can assist utilities in meeting regulatory requirements during drinking water treatment.     

Ozonation/Post-Chlorination of Humic Acid: A Model for Predicting Drinking Water Disinfection By-Products

Experiments were performed to evaluate disinfection by-products in model humic acid solutions which were ozonated at three different ozone to carbon levels and then chlorinated. These experiments were conducted in order to help understand whether the ozone/post-chlorination process alters the amount and type of mutagenic by-products formed, from those produced by chlorination of humic acid alone. Disinfection by-products were identified by gas chromatography/mass spectrometry (GC/MS). Samples of clarified and sand-filtered Mississippi River water at a pilotscale drinking water treatment plant in Jefferson Parish, Louisiana, that were ozonated and post-disinfected with chlorine, also were analyzed by GC/MS. A comparison of the by-products in the pilot plant study versus those in our laboratory study showed that similar compounds were produced. The effect of bromide ion in the pilot plant water on by-product formation also is discussed.     

原水天然有机物化学特性与消毒副产物关系

原水氯消毒过程中,氯会与水中的天然有机物(NOM)反应,生成三卤甲烷、卤乙酸等消毒副产物(DBPs).为了选择有效的饮用水净化工艺,控制消毒副产物的生成,研究天然有机物的化学特性及与消毒副产物的关系,是十分必要的.在总结NOM相似组分化学分离方法的基础上,概括了不同水源中NOM及各组分溶解性有机砌(DOC)的含量,对消毒副产物的贡献,化学组成以及可能生成DBPs的化学结构.不同水源中NOM及各组分DOC含量不同,相同组分对消毒副产物的贡献也有很大的差别,且NOM各组分的化学组成有一定的重叠,对生成DBPs的化学结构需继续研究.