Formation of disinfection byproducts in typical Chinese drinking water

Eight typical drinking water supplies in China were selected in this study. Both source and tap water were used to investigate the occurrence of chlorinated disinfection byproducts (DBPs), and seasonal variation in the concentrations of trihalomethanes (THMs) of seven water sources was compared. The results showed that the pollution level for source water in China, as shown by DBP formation potential, was low. The most encountered DBPs were chloroform, dichloroacetic acid, trichloroacetic acid, and chlorodibromoacetic acid. The concentration of every THMs and haloacetic acid (HAA) compound was under the limit of standards for drinking water quality. The highest total THMs concentrations were detected in spring.     

组合氯化消毒工艺的卤代消毒副产物生成特性

比较4种单独使用氯或组合氯化消毒工艺在较长管网停留时的卤代消毒副产物生成情况.4种工艺为单独游离氯消毒、氯胺消毒、清水池游离氯消毒后转氯胺的先氯后氨消毒、短时游离氯后转氯胺的顺序氯化消毒工艺.结果表明,游离氯消毒工艺在管网停留时间长时,卤代消毒副产物会持续大量的生成,而一氯胺消毒工艺生成的卤代消毒副产物量很低.目前使用较为普遍的先氯后氨消毒工艺与游离氯消毒相比,可以降低卤代消毒副产物的生成量,管网停留24 h时,三卤甲烷的生成量降低了9.6%,卤乙酸的生成量减低了42%.但是先氯后氨消毒工艺由于游离氯接触时间约为2 h,卤代消毒副产物已经大量生成.短时游离氯后转氯胺的顺序氯化消毒工艺,由于控制了游离氯的接触时间,可以在保障消毒工艺灭活微生物效果的同时更为有效地控制卤代消毒副产物,管网停留24 h时,三卤甲烷的生成量与单独游离氯消毒工艺相比降低了48%,卤乙酸的生成量减低了72%.因此,顺序氯化消毒工艺可以更好地控制卤代消毒副产物的生成,提高水质安全性.     

Disinfection byproduct precursor removal by enhanced coagulation and their distribution in chemical fractions

Raw water from the Songhua River was treated by four types of coagulants, ferric chloride(FeCl3), aluminum sulfate(Al2(SO4)3),polyaluminum chloride(PACl) and composite polyaluminum(HPAC), in order to remove dissolved organic matter(DOM). Considering the disinfection byproduct(DBP) precursor treatability, DOM was divided into five chemical fractions based on resin adsorption.Trihalomethane formation potential(THMFP) and haloacetic acid formation potential(HAAFP) were measured for each fraction. The results showed that hydrophobic acids(HoA), hydrophilic matter(HiM) and hydrophobic neutral(HoN) were the dominant fractions.Although both HoN and HoA were the main THM precursors, the contribution for THMFP changed after coagulation. Additionally,HoA and HiM were the main HAA precursors, while the contribution of HoN to HAAFP significantly increased after coagulation.HoM was more easily removed than HiM, no matter which coagulant was used, especially under enhanced coagulation conditions.DOC removal was highest for enhanced coagulation using FeCl3 while DBPFP was lowest using PACl. This could indicate that not all DOC fractions contained the precursors of DBPs. Reduction of THMFP and HAAFP by PACl under enhanced coagulation could reach51% and 59% respectively.     

不同管材对氯胺消毒副产物生成与水质生物稳定性的影响

模拟考察了上海某水厂出厂水在不同输配管网体系中水质的变化规律,研究了管材和氯胺投加量对输配过程水质变化的影响.结果表明,不同输配管网体系氯胺的衰减速率总体上符合如下规律:镀锌管>铜管>不锈钢管>聚乙烯管(PE管)>三型聚丙烯管(PPR管),季节因素对氯胺衰减速率影响较大,秋冬季节氯胺衰减的速率显著降低;消毒副产物三卤甲烷(THMs)和卤乙酸(HAAs)的生成规律为:PE管?PPR管>玻璃管>不锈钢管>铜管>镀锌管;五种管材中异氧菌总数(HPC)的生长数量为:镀锌管>>PE管>不锈钢管>PPR管>铜管;铜管和PE管中生物可同化有机碳(AOC)显著高于其余管材及出厂水.     

生物降解与吸附作用协同去除卤乙酸生成势

评价了生物强化活性炭(BAC)的生物降解与吸附作用协同对消毒副产物前体物质(DBPFP)的控制效果.控制 BAC 的空床接触时间(EBCT)为 20min 时,BAC 对卤乙酸生成势(HAAFP)的去除率达到 59%,而相同条件下,普通颗粒炭(GAC)对其去除率只有 27%.BAC 工艺中微生物数量和微生物活性均明显高于 GAC 工艺.通过微生物降解作用和活性炭吸附作用的协同,BAC 对 HAAFP 的去除率与 EBCT 具有明显的线性相关性(R²=0.9069).BAC 出水中指标 UV254与 HAAFP 也表现出一定的线性相关性(R²=0.7702).     

有机肥施用下稻田田面水中消毒副产物前体物的赋存规律

稻田有机肥输入会使田面水含有含量的溶解性有机碳(DOC).溶解性有机物(DOM)是具有三致效应的消毒副产物(DBPs)的前体物,而DOC是用于表征DOM浓度的一个指标.本研究旨在评估水稻田田面水的三卤甲烷(THMs)前体物的生成反应性,解析猪粪有机肥对于THMs前体物从水稻田输出的潜在影响.于水稻种植季选取4个猪粪施用梯度(以C计,下同)(0[对照],714.1[低],1428.2[中]与2142.3[高]kg·hm-2),检测了稻田田面水中的DOC,UVA254与三卤甲烷生成潜能(THMFP).结果表明,3个指标两两之间呈线性相关性.田面水中以上3个指标都与有机肥施用量呈正相关性.在施肥后的7d内,DOC的输出潜能降低了32.9%至47.5%.有机肥施用与预期的降雨或灌溉之间的时间间隔相隔一周以上,将能在满足作物营养需求的条件下降低消毒副产物前体物输出的风险,使稻田土壤成为DOC的汇而非DOC输出至周边水体的源.     

Carbonaceous and nitrogenous disinfection by-product formation in the surface and ground water treatment plants using Yellow River as water source

This work investigated the formation of carbonaceous and nitrogenous disinfection by-products (C-DBPs, N-DBPs) upon chlorination of water samples collected from a surface water and a ground water treatment plant (SWTP and GWTP) where the conventional treatment processes, i.e., coagulation, sedimentation, and filtration were employed. Twenty DBPs, including four trihalomethanes, nine haloacetic acids, seven N-DBPs (dichloroacetamide, trichloroacetamide, dichloroacetonitrile, trichloroacetonitrile, bromochloroacetonitrile, dibromoacetonitrile and trichloronitromethane), and eight volatile chlorinated compounds (dichloromethane (DCM), 1,2-dichloroethane, tetrachloroethylene, chlorobenzene, 1,2-dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene and 1,2,4-trichlorobenzene) were detected in the two WTPs. The concentrations of these contaminants were all below their corresponding maximum contamination levels (MCLs) regulated by the Standards for Drinking Water Quality of China (GB5749-2006) except for DCM (17.1 μg/L detected vs. 20 μg/L MCL). The SWTP had much higher concentrations of DBPs detected in the treated water as well as the DBP formation potentials tested in the filtered water than the GWTP, probably because more precursors (e.g., dissolved organic carbon, dissolved organic nitrogen) were present in the water source of the SWTP.     

J市饮用水氯消毒副产物分析及其健康风险评价

J市位于太湖下游,其水源水质受上游和自身工农业发展的影响,有机物和氨氮浓度较高,氯消毒副产物及其引发的健康风险广泛受到关注.2012年5、8、10月以及2013年1月采样,使用气相色谱法分析了J市饮用水中4种三卤甲烷和5种卤乙酸的含量,发现自来水中三卤甲烷浓度占三卤甲烷与卤乙酸总和的88.1%以上,5月、8月和次年1月浓度较高(分别为39.34、50.37和28.02μg.L-1),10月浓度(19.19μg.L-1)较低,远高于卤乙酸的浓度(2.58～4.02μg.L-1).自来水煮沸3min后,三卤甲烷可去除92.3%以上,但卤乙酸会大幅度增加.基于EPA推荐的健康风险评价模型对经口摄取途径时氯消毒副产物的致癌和非致癌风险进行计算,发现化学致癌物质的健康风险为3.1×10-6～7.3×10-6,高于可接受风险水平1×10-6;煮沸后致癌物质的健康风险大幅度降低至7.9×10-7,低于可接受风险水平.煮沸后非致癌氯消毒副产物的健康风险由2.1×10-11显著升高至3.4×10-9,未超过10-5的风险管理参考值.     

Removal of disinfection by-products formation potential by biologically intensified process

The removal of disinfection by-products formation potential(DBPFP) in artificially intensified biological activated carbon(IBAC) process which is developed on the basis of traditional ozone granular activated carbon was evaluated. By IBAC removals of 31% and 68% for THMFP and HAAFP were obtained respectively. Under identical conditions, the removals of the same substances were 4% and 32% respectively only by the granular activated carbon(GAC) process. Compared with GAC, the high removal rates of the two formed potential substances were due to the increasing of bioactivity of the media and the synergistic capabilities of biological degradation cooperating with activated carbon adsorption of organic compounds. A clear linear correlation ( R^2 = 0.9562 and R^2 = 0.9007) between DOC HAAFP removal rate and Empty Bed Contact Time(EBCT) of IBAC process was observed, while that between THMFP removal rate and EBCT of GAC was R^2 = 0.9782. In addition certain linear correlations between THMFP, HAAFP and UV254 ( R^2 = 0.855 and R^2 = 0.7702) were found for the treated water. For IBAC process there are also more advantages such as long backwashing cycle time, low backwashing intensity and prolonging activated carbon lifetime and so on.     

焦化废水尾水O3氧化消除消毒副产物生成潜能的影响分析

焦化废水经生化处理后的尾水中含有多种溶解性有机物(DOM),可能成为消毒副产物的前体物,进而影响受纳水体下游给水厂的水质安全.因此,对焦化废水外排水(尾水)的消毒副产物生成潜能进行了分析,以实际焦化废水厂尾水为基质,采用气相色谱(GC)考察了O3氧化深度处理前后卤乙腈和三卤甲烷的生成潜能,并结合分子质量分布法和三维荧光光谱法分析了O3氧化处理尾水过程中前体物的转化规律.GC结果表明,焦化废水尾水各个分子质量范围的卤乙腈和三卤甲烷生成潜能分别达到1950.5～3965.1μg.L-1和1498.2～2571.2μg.L-1,表明工业废水排放之前需要考虑其对水体消毒副产物生成潜能的贡献.O3氧化作用可以实现尾水中消毒副产物前体物的削减,相同反应时间的条件下O3浓度越高其削减越有效.溶解性有机碳(DOC)及在254nm波长下的吸光度值(UV254)分析结果表明,O3氧化能部分矿化尾水中的有机物,并优先分解不饱和芳香性有机组分.分子质量和荧光光谱分析结果表明,O3氧化优先矿化小分子组分(<1kDa),并将尾水中大分子有机物分解为小分子(<1kDa),对活泼基团进行预氧化,从而实现氯消毒副产物生成潜能的削减.     

氯、氯胺消毒下钱江源水源水消毒副产物形成特征研究

以钱江源水源水为研究对象,以氯、氯胺为消毒方式,研究了不同消毒条件下,三卤甲烷(THMs)、卤乙腈(HANs)、氯代酮(CKs)、二卤乙酸(DHAAs)、三卤乙酸(THAAs)等消毒副产物(DBPs)的形成情况,以便为水务工作者监测钱江源建库前后水质、DBPs形成的变化提供基础数据.结果显示,氯消毒下DBPs的产量比氯胺消毒高出3~7倍甚至1个数量级,但不管是氯消毒还是氯胺消毒,THMs、HAAs形成量均在我国饮用水标准范围内.氯消毒下,大部分DBPs产量为中、碱性条件酸性条件(除了CKs),氯胺消毒则呈现不同的情况(所有DBPs的产量均为p H=6、p H=7p H=8).消毒剂量对所有DBPs形成具有明显的促进作用;溴离子对THMs、DHANs、DHAAs的形成有明显的促进作用.进一步研究表明,钱江源水源水的水质比钱塘江下游九溪水源水好,DBPs形成也较低,某些指标(如有机碳、有机氮、HANs形成量等)甚至比同省水质较好的金兰水库还要好;而且由于其较高的比紫外吸收值(SUVA),DBPs的溴嵌入能力均比九溪水源水、金兰水库低.此外,就目前的钱江源水源水来说,控制消毒剂量(氯、或氯胺)是控制DBPs形成的有效策略.     

臭氧活性炭工艺中卤乙酸生成潜能与相对分子质量分布关系的研究

通过臭氧生物活性炭和微曝气生物活性炭(O₃/BAC和micro-aeration/BAC)2套工艺研究其对不同相对分子质量有机物去除特点和不同相对分子量有机物生成的卤乙酸及其去除特性.结果表明,O₃/BAC工艺对相对分子质量区间>30×10³的有机物去除率超过90%.O₃/BAC与micro-aeration/BAC出水中,UV₂₅₄值表示相对分子质量<103的有机物超过50%,相对分子量区间在10×10³～30×10³的有机物占20%～30%;在O₃/BAC和微曝气/BAC工艺出水中,以相对分子质量<10³的有机物生成的卤乙酸最多,生成DCAA、TCAA、DBAA分别为97.00、38.55、2.10μg/L和104.00、42.75和2.92μg/L;采用各处理单元不同分子量有机物与氯反应生成的DCAA、TCAA、DBAA和THAAs与相对应的UV₂₅₄值进行线性拟合,相关系数分别为0.827、0.851 3、0.815 7和0.878.UV₂₅₄与臭氧生物活性炭处理工艺出水中的卤乙酸生成潜能具有较好的线性关系.     

冬季Z市水源DOM组成、三卤甲烷生成势特性及去除研究

以冬季Z市水源地2条入库河流为研究对象,通过联合运用三维荧光光谱、树脂分离分级和紫外可见分光光度法,探究水源地原水中溶解性有机物（DOM）的荧光成分、来源、组成、腐殖化程度与消毒副产物三卤甲烷（THMs）生成势的关系。结果表明：三维荧光光谱解析出水源地2条入库河流原水中共有类蛋白物质（C1）、紫外腐殖酸类物质（C2）、陆地/人造腐殖质类物质（C3）3个荧光峰;水源地的2条入库河流（Q河与X河）的3个荧光峰峰值分别为4.50、10.75、7.56和1.33、9.24、7.56;荧光源指数（FI）与生物源指数（BIX）均体现出水源地原水中的DOM主要为陆源输入;此外,水源地原水中的DOM化学分级之后,5个组分浓度表现为疏水性有机酸（HoA）>亲水物质（HiM）>疏水中性有机物（HoN）>疏水碱性有机物（HoB）>弱疏水酸性有机物（wHoA）;Q河原水氯化后产生CHCl₃、CHClBr₂和CHBrCl₂ 3种成分,X河氯化后产生CHCl₃和CHBrCl₂ 2种成分,说明河水并没未受到明显的工业污染。水源地2条入库河流原水的DOM各化学分级组分的THMs生成势的研究结果表明,THMs的主要前驱物为HoA和HiM,而HoA、HiM、wHoA 3种组分对THMs的生成能力均较强,与紫外吸收特性SUVA相一致,说明生成THMs的能力也很强,应选取工业聚合氯化铝进行强化混凝去除。     

几种模型物质在氯化中形成THMs、HAAs的特性研究

以胃蛋白酶(蛋白质)、谷胱甘肽(氨基酸多肽)、葡萄糖(糖类)作为模型物质代表藻来源有机物,并以Fluka腐殖酸为对照,研究其耗氯量、三卤甲烷(主要是氯仿)、卤乙酸(主要是二氯乙酸(DCAA)、三氯乙酸(TCAA))的形成情况.结果显示4种模型物质在氯化后,其余氯在前2 h迅速降低,6 h后则下降速度渐缓;其中耗氯量最大的是谷胱甘肽(96 h:7.1 mg·mg^-1(以每毫克碳计,下同)),其次是胃蛋白酶(96 h:4.2 mg·mg^-1)、腐殖酸(96 h:3.0 mg·mg^-1),而葡萄糖最小(96 h:0.7 mg·mg^-1).4种模型物质氯仿、DCAA、TCAA的生成速度也是在起初的2 h较快,随后渐缓;但从单位碳的产量来看,腐殖酸和胃蛋白酶形成氯仿(96h: 15.1~55.2 μg·mg^-1(以每毫克碳计,下同))、DCAA(96 h: 15.1~55.2 μg·mg^-1)、TCAA(96h: 15.1~55.2 μg·mg^-1)均较多,而谷胱甘肽、葡萄糖则相对较少(氯仿-96 h:2.5~5.1 μg·mg^-1;DCAA-96 h:0.6~8.0 μg·mg^-1;TCAA-96 h:0.12~3.8 μg·mg^-1);而从前驱物特性来说,氯仿、TCAA的前驱物具有较高的芳香度(即高的SUV₂₅₄值),而DCAA前驱物的SUV₂₅₄相对较低.对于富含蛋白质、多肽、糖类等的富营养化饮用水源,则要格外注意饮用水中DCAA所带来的健康风险.     

Preozonation of bromide-bearing source water in south China

The effectiveness of preozonation was evaluated on treating a bromide-bearing dam source water in south China through batch-scale experiments. Preozonation at ozone doses of 0.5-1.0 mg/L （at ozone consumption base） enhanced total organic carbon （TOC） removal through coagulation, and resulted in an almost linear reduction of ultraviolet absorbance at 254 nm （LW2s4）. The removals of TOC （after coagulation） and UV254 at the ozone dose of 1.0 mg/L were 36% and 70%, respectively. Preozonation at an ozone dose between 0.5 and 1.0 mg/L resulted in the removal of disinfection byproducts formation potential （DBFP） including trihalomethane formation potential （THMFP） and haloacetic acid formation potential （HAAFP） for about 50%. The removals of THMFP and HAAFP decreased with the further increase of ozone dose. Ozonation of bromide-bearing water （bromide concentration, 34 μg/L） produced a bromate concentration under the detection limit（2μg/L） at ozone doses 〈1.5 mg/L. However, bromate 〉10μg/L could be produced when the bromide concentration was increased to 96 μg/L.     

配水管网中生物稳定性和消毒副产物的变化及相关性

研究了上海市2条不同水源水厂配水管网中可同化有机碳（AOC）、三卤甲烷（THMs）和卤乙酸（HAAs）的变化情况,并对饮用水生物稳定性和消毒副产物间的相关性进行了分析.结果表明,管网中AOC和HAAs含量受余氯和微生物活动双重作用的影响,在距水厂较近、余氯较高的管网中,可能因氯与有机物继续反应出现上升,在余氯较低的管网末梢则因为微生物降解作用使含量下降;THMs含量则只受余氯的影响,随管网延伸持续增长.HAAs与AOC含量间存在较好的线形关系,前体物间具有相似性,THMs与AOC含量间呈正相关性;作为饮用水安全性的2个重要方面,生物稳定性和消毒副产物间具有内在的关联性.     

Acute toxicity formation potential of benzophenone-type UV filters in chlorination disinfection process

Benzophenones （BPs） are a class of widely used UV filters, which have been frequently detected within multiple environmental matrices. Disinfection is a necessary process in water treatment processes. The transformation behaviors and toxicity changes of 14 BP-type UV filters during chlorination disinfection treatment were investigated in this study. A new index, the acute toxicity formation potential, was proposed to evaluate the toxicity changes and potential risks of BP-type UV filters during chlorination treatment. It was found that 13 of 14 BP-type UV filters exhibited toxicity decreases in the chlorination disinfection process, more or less, while one showed a toxicity increase. The toxicity changes were dependent on substitution effects, such that 2,4-di-hydroxylated or 3-hydroxylated BPs exhibited significant toxicity decreases after chlorination treatment due to the ready cleavage of the aromatic ring. Importantly, the acute toxicity changes could be duplicated in an ambient water matrix.     

臭氧与氯联合消毒对钱塘江水源水DBPs形成及溴取代的影响

本文研究了在pH 6～8、反应时间2～72 h、反应温度10～30℃条件下,钱塘江水源水在臭氧-氯消毒联合作用下,三卤甲烷(THMs)、二卤乙酸(DHAAs)、三卤乙酸(THAAs)、二卤乙腈(HANs)、三卤硝基甲烷(THNMs)等5类消毒副产物(DBPs)的形成和溴取代特征.结果显示,臭氧-氯消毒下DBPs的形成与氯消毒有较多相似之处:①大部分DBPs形成量均随着温度的升高、时间的延长而增加,相应的溴取代因子(BSFs)则随着时间的延长、温度的上升而呈下降趋势;②氯代DHANs倾向于在酸性条件下形成多,而溴代DHANs则倾向于在碱性条件下形成多;③不管是氯消毒还是臭氧-氯消毒,也不管是哪种消毒条件,5类DBPs的BSF值顺序均为BSF_(HNMs)BSF_(DHANs) BSF_(THAAs)BSF_(THMs)≈BSF_(DHAAs).但与氯消毒不同的是,臭氧-氯消毒下THMs、DHAAs、THAAs、HANs的形成产量更低,而THNMs的产量则更高;而且与氯消毒相比,臭氧-氯消毒普遍增加了DBPs的溴取代程度,也改变了溴离子在不同DBPs之间的分配,即减少了THMs、DHAAs、THAAs、DHANs对溴的利用率,但大幅增加了HNMs的溴利用率.鉴于溴代HNMs的极高毒性,因此对于钱塘江水源水,臭氧-氯消毒要注意HNMs带来的健康风险.     

长三角部分水源水氯化消毒后卤乙酸形成的多元回归模型研究

以长三角比较有代表性的3处水源(太湖、钱塘江、金兰水库)为实验对象,研究不同消毒条件下9种卤乙酸(haloacetic acids,HAAs)的形成及其影响因素,并通过建立多元回归模型来评估水源水氯化后HAAs的形成.结果表明:HAAs的形成水平依次为太湖钱塘江金兰水库,且均以二卤乙酸(dihaloacetic acid,DHAA)、三卤乙酸(trihaloacetic acid,THAA)为主.二氯乙酸(dichloroacetic acid,DCAA)、总二卤乙酸(ΣDHAA)、HAA5(USEPA规定的5种HAAs)、HAA9(9种HAA的简称)的回归模型具有良好的预测潜力,准确率达83.3%~94.4%,而三氯乙酸(trichloroacetic acid,TCAA)、一溴二氯乙酸(bromodichloroacetic acid,BDCAA)、ΣTHAA(总三卤乙酸)模型的预测准确率较低,只有47.2%~61.1%.根据偏相关系数分析,影响DCAA、ΣDHAA、HAA5的关键的因子是溶解性有机碳;影响TCAA、ΣTHAA、HAA9的关键的因子是投氯量;影响BDCAA形成的最关键因子是溴离子.     

MBR处理医院污水后续氯消毒及其消毒副产物研究

针对医院污水中致病微生物的特殊排放要求,研究了膜生物反应器（MBR）应用于医院污水处理中的预消毒及其后续氯消毒特性.结果表明,在工程应用中MBR具有显著的预消毒作用,对医院污水中的细菌总数和粪大肠杆菌的去除率分别达到2.0～3.1 lg和2.8～4.0 lg;对于MBR出水中残留的微生物,采用次氯酸钠进行后续消毒,当接触时间为1 h,在有效氯浓度为0.8 　mg/L时,可检测不出粪大肠杆菌,且放置6 h未见再生长,相应的THMs和HAAs分别为16.94 μg/L和32.10 μg/L;固定接触时间,随着Cl₂/DOC值的增加,MBR出水中THMs和HAAs均近似呈线性增长趋势（r²分别为0.941?5和 0.965?2）,且HAAs的增长速率高于THMs.