活性炭吸附对藻类有机物的去除及其消毒副产物的控制

本文研究了粉末活性炭(powder activated carbon,PAC)吸附对藻类有机质(algal organic matter,AOM)及其典型含氮和非含氮消毒副产物(disinfection by-products,DBPs)的去除效能.结果表明,AOM主要含有一些小分子量、亲水性、低芳香度的有机质,三维荧光光谱证实,PAC吸附改变了AOM的组成,明显降低了类腐殖质物质含量,但对芳香蛋白类物质去除能力有限.PAC投加量为20 mg·L~(-1),吸附时间10~30 min时,对于3.30 mg·L~(-1)的胞内有机质(intracellular organic matter,IOM)和胞外有机质(extracellular organic matter,EOM)溶液,溶解性有机碳去除率分别为20.7%~31.9%和12.6%~19.0%.PAC对IOM和EOM中卤代甲烷总生成量的最高去除率分别为26.6%和35.8%;卤代乙腈总生成量的最高去除率分别为49.6%和53.6%,其中二溴乙腈前体物的去除效果显著.PAC对EOM氯化生成的DBPs的控制作用较好.     

臭氧对生物活性炭中微生物及出水消毒副产物的影响

为探究饮用水处理过程中臭氧(O_3)对生物活性炭(BAC)中微生物及出水消毒副产物(DBPs)的影响,以饮用水小试装置的O_3-BAC工段开展研究,系统分析在不同O_3浓度下的水质变化,溶解性有机物(DOM)特征,微生物活性和DBPs产生情况.结果表明,O_3对BAC过滤的影响主要表现为提升微生物对DOM的利用效率,但O_3浓度过高会导致出水中蛋白质和微生物代谢产物(SMPs)等有机物增加.当O_3浓度从0 mg·L~(-1)提升到2. 0 mg·L~(-1)时,BAC中微生物存活率从95. 10%降至62. 60%,但O_3将出水中难降解有机物转变为易生物降解物质,使得微生物活性提高了62. 52%,BAC的生物过滤得到强化;当O_3浓度增加到4. 0 mg·L~(-1)时,微生物存活率降至49. 90%,同时微生物产生的蛋白质和SMPs增加,导致含碳消毒副产物(CDBPs)和含氮消毒副产物(N-DBPs)的生成浓度与不通O_3相比分别上升41. 93%和7. 18%,大大增加水体潜在危险.综上,合适O_3浓度有利于O_3-BAC对DOM的去除,O_3浓度过高会导致BAC过滤效果变差并产生新的DBPs前体物.     

高藻水臭氧预氧化过程有机物转化及消毒副产物生成势

研究了高藻水预氧化处理过程中,不同臭氧氧化程度及不同pH值条件下,藻类有机物释放与转化规律以及氯化消毒副产物(DBPs)的生成特性.结果表明,臭氧投加量为28.92 mg·L-1时藻去除率达36%.随着臭氧投加量的增加,藻的去除率进一步增加,类腐殖酸先增加后持续减少,溶解性微生物代谢产物、类富里酸和类芳香蛋白物质持续减少;低投加量的臭氧对二氯乙腈(DCAN)、三氯乙腈(TCAN)生成势有明显的控制作用,但会增加三氯硝基甲烷(TCNM)以及1,1,1-三氯丙酮(1,1,1-TCP)前体物,随臭氧投加量增大,DBPs生成势显著增大.酸性条件下臭氧对藻的去除效果最好,UV254以及总有机碳(DOC)均随pH的增大有所上升,但变化较小;臭氧氧化可降解溶解性微生物代谢产物,降解效果受pH影响较小,类腐殖酸有机物随pH值增大而减少;DCAN、TCAN生成势随pH增大有所降低,TCNM生成势在pH=10条件下最高,1,1,1-TCP生成势在pH=7条件下最高.     

全球饮用水标准中消毒副产物管控指标对比与启示

饮用水水质安全是关乎千家万户的重大民生问题,其中消毒工艺是保障饮用水微生物安全不可或缺的重要措施,然而由消毒剂与前体物反应生成的DBPs（消毒副产物）被发现具有潜在的健康风险,如致癌及引起发育副作用等.随着对饮用水中DBPs的重视程度不断提高,世界上多个国家、地区或组织将DBPs指标纳入标准.为对我国饮用水水质标准中DBPs指标的制定和修订提出可参考的建议,比较了国内外饮用水和再生水饮用回用水质标准中的DBPs指标,包括DBPs种类、对应的浓度限值和监测要求等.结果表明:①我国饮用水水质标准中涵盖的DBPs种类较多,其中地方标准相较于国标而言对DBPs指标的要求更为严格,但较少考虑综合性指标（如总有机卤素）和高毒性含氮DBPs（如卤乙腈）;②国外多部饮用水水质标准或准则中包含一些无浓度限值规定但已知具有较高健康风险的DBPs,此举可指导有关部门进一步开展浓度调研和毒性试验,为未来水质标准的制定提供参考依据.研究显示,我国饮用水标准中DBPs指标需要考虑综合性指标的选取与管控以及高风险指标的甄别和筛查,另外还需因地制宜加强地方性标准的建设工作.      

基于自适应神经模糊推理系统和简单水质指标预测供水系统三卤甲烷的浓度

消毒副产物(DBPs)因其潜在的致癌、生殖毒性成为饮用水安全的重要隐患.及时知晓供水系统中DBPs浓度是防控DBPs健康风险的前提.然而目前DBPs仪器监测存在过程繁琐、成本高昂、时间滞后等问题.利用常规水质指标建立高质量的预测模型是重要出路.基于此,本研究选择3个简单的水质指标pH、温度、UVA₂₅₄,利用自适应模糊神经网络(ANFIS)建立了供水系统中三卤甲烷(THMs,最常见的DBPs)分布的预测模型.结果显示,当隶属函数(MF)分别为”gaussmf”、“gbellmf”、“trapmf”,MF数量分别为3、3、3时,建立的总三卤甲烷(T-THMs)、三氯甲烷(TCM)、一溴二氯甲烷(BDCM)模型的预测效果最好.其中,T-THMs、TCM模型质量较高：预测值与实测值的相关系数(r)为0.871～0.880,预测误差(MARE)为11%,预测准确率(N_E<25%)为92%～95%;与T-THMs、TCM相比,BDCM模型的预测效果略差(r=0.775,MARE=16%,N_E<25%=83%),但也在可...     

水中藻类溶解性有机物特性研究

试验从分子量分布、三维荧光光谱和亲疏水特性3个方面研究了水中藻类(鱼腥藻、小球藻和小环藻)溶解性有机物(AOM)的特性。结果表明,3种AOM有机物在分子量分布上大分子和中小分子有机物各占一定比例。鱼腥藻AOM和小球藻AOM均表现出大分子和小分子有机物所占比例较大,中等分子有机物所占比例较小;小环藻AOM所含大分子有机物的比例相对较小,中小分子有机物是小环藻AOM的主要组成部分。荧光光谱分析得出,鱼腥藻AOM的大分子有机物主要是大分子蛋白类和腐植酸类有机物,中小分子有机物主要是小分子糖类和大分子疏水性腐殖类有机物的分解产物。小球藻AOM大分子有机物以大分子蛋白质类为主,中小分子有机物含有较多的蛋白类和腐殖酸类物质。而小环藻AOM大分子有机物主要以大分子腐殖酸类为主,中小分子有机物腐殖酸类物质含量也较多。亲疏水性分析表明,藻类AOM呈现较强的亲水特性,其SUVA值较低,主要是由亲水性的多糖和蛋白类有机物组成,疏水性腐殖类有机物质的含量相对较少。     

浙江省H市供水系统消毒副产物及其健康风险评价

以浙江省H市供水系统为调查对象,采用配有电子捕获器的气相色谱(GC-ECD)检测2座水厂及相应供水管网中18种消毒副产物(DBPs)的含量,深入探讨了DBPs导致的饮用水健康风险及前体物指标与各类DBPs的相关性.结果发现H市饮用水中检出三卤甲烷(THMs)、卤乙酸(HAAs)、卤乙腈(HANs)和三氯硝基甲烷(HNMs)等类消毒副产物,THMs含量最高,HAAs次之.CX水厂出水和供水管网中THMs分别为7. 70～32. 73μg·L~(-1)和9. 00～51. 42μg·L~(-1),HAAs分别为3. 05～21. 30μg·L~(-1)和6. 00～26. 79μg·L~(-1). TH水厂出水和供水管网中THMs分别为8. 65～38. 76μg·L~(-1)和12. 09～42. 04μg·L~(-1),HAAs分别为2. 42～14. 79μg·L~(-1)和2. 80～33. 40μg·L~(-1),2家水厂出厂水和供水管网中消毒副产物浓度均符合《生活饮用水卫生标准》(GB 5749-2006).采用溶解性有机碳(DOC)和UV254表征水样有机物,分析有机物与DBPs的相关性,发现管网水中三氯甲烷(TCM)与DOC和UV254呈显著负相关性.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H市出厂水和管网水中消毒副产物引起的致癌风险分别为5. 94×10-6～4. 76×10-5和5. 94×10-6～5. 56×10-5,非致癌风险分别为0. 91×10-2～4. 20×10-2和1. 26×10-2～4. 72×10-2.致癌风险主要来自THMs,一溴二氯甲烷(BDCM)贡献了最高的致癌风险,非致癌风险主要来自TCM.     

藻类对纳滤膜去除萘普生的影响

传统的饮用水处理工艺不能有效地去除水中痕量有机物PPCPs,纳滤(NF)膜工艺对其有较好的去除效果。水中有机物(DOM)的存在对NF膜去除PPCPs有较大的影响,藻类有机物(AOM)的组成及特性不同于天然有机物,它在膜处理工艺中对膜污染有重要的影响。试验研究了2种藻类(鱼腥藻、小球藻)AOM对纳滤膜去除萘普生(NPX)的影响效果。结果显示2种藻类AOM均能促进NF膜对NPX的分离,提高NPX的去除率,但会显著降低膜通量。AOM的分子量分布和亲疏水性与其对NPX去除率的影响有关,AOM中亲水性的多糖和蛋白类有机物质是造成膜污染和影响NPX去除率的主要物质。滤饼层的形成改变了膜表面的亲疏水性能和截流分子量(MWCO),也是造成膜通量衰减和NPX去除率提高的重要原因。     

饮用水中的消毒副产物及其控制策略

消毒副产物（disinfection by-products,DBPs）是在饮用水消毒时由消毒剂与有机或无机前体物反应生成的一类次生污染物,其由于具有致癌、致畸和致突变的三致特性在全球范围内广受关注.聚焦于饮用水中的DBPs,介绍了DBPs的主要分类和研究历程,汇总了多地饮用水中常见DBPs的浓度水平以及全球饮用水水质标准对DBP指标的管控要求.随后系统介绍了饮用水中DBPs的控制策略,包括源头控制、过程控制、末端控制以及协同控制这4大类,并对各类控制方法的优缺点进行了分析.评述了中国的DBPs研究的现有水平和未来趋势,并展望了未来有关DBPs控制方法的研究方向.一方面,在评价某种工艺或技术对DBPs的控制效果时需要考虑DBPs浓度和水质综合毒性的变化,另一方面,建议关注耦合源头、过程和末端控制技术的协同控制方法,兼顾从源头到龙头每个节点,实现对饮用水中各类DBPs的高效控制.     

微生物对饮用水典型消毒副产物前体物的降解效能及其群落特征

相对于CF（氯仿）等C-DBPs（含碳消毒副产物）,DCAN（二氯乙腈）等N-DBPs（含氮消毒副产物）具有更高的毒性.控制DBPs（消毒副产物）的前体物是抑制DBPs产生的最有效方法之一.为考察微生物降解DBPs前体物对生成DBPs的影响,分别选取C-DBPs和N-DBPs的典型代表物CF和DCAN及其相应的典型前体物Tyr（酪氨酸）和Asp（天冬氨酸）为研究对象,采用微生物培养前体物的方式,探究微生物对典型前体物Tyr和Asp的降解效果及其对生成CF和DCAN的控制效果.结果表明:①Tyr和Asp两种前体物经微生物降解后,DOC（溶解性有机碳）的去除率分别为94.0%和85.6%,DON（溶解性有机氮）的去除率分别为69.0%和81.0%.②在前体物经微生物降解后的水样中,氯化或氯胺化消毒后生成CF和DCAN的量较降解前均大大减少.以Tyr为前体物,水样经微生物降解、氯化消毒后生成CF和DCAN的量分别降低了56.1%和89.5%,氯胺化消毒后生成CF的量降低了68.5%;以Asp为前体物,水样经微生物降解、氯化消毒后生成DCAN的量最高可降低99.9%,经微生物降解、氯胺化消毒后生成的CF可降低50.7%.③对水样中微生物菌群分析发现,在门水平上的菌群主要有变形菌门（Proteobacteria）、放线菌门（Actinobacteria）和拟杆菌门（Bacteroidetes）,在属水平上的菌属主要有伯克氏菌属（Burkholderia-paraburkholderia）、半角藻属（Haliangium）、分枝杆菌属（Mycobacterium）、沉积小杆菌属（Sediminibacterium）、norank_f_Chitinophagaceae和动胶菌属（Zoogloea）.研究显示,微生物降解对DBPs典型前体物Tyr和Asp的去除,以及对生成CF和DCAN的控制具有较大的潜力,变形菌和放线菌在降解DBPs前体物中起到了重要作用.      

Formation of regulated and unregulated disinfection byproducts during chlorination and chloramination: Roles of dissolved organic matter type, bromide, and iodide

Algal blooms and wastewater effluents can introduce algal organic matter (AOM) and effluent organic matter (EfOM) into surface waters, respectively. In this study, the impact of bromide and iodide on the formation of halogenated disinfection byproducts (DBPs) during chlorination and chloramination from various types of dissolved organic matter (DOM, e.g., natural organic matter (NOM), AOM, and EfOM) were investigated based on the data collected from literature. In general, higher formation of trihalomethanes (THMs) and haloacetic acids (HAAs) was observed in NOM than AOM and EfOM, indicating high reactivities of phenolic moieties with both chlorine and monochloramine. The formation of haloacetaldehydes (HALs), haloacetonitriles (HANs) and haloacetamides (HAMs) was much lower than THMs and HAAs. Increasing initial bromide concentrations increased the formation of THMs, HAAs, HANs, and HAMs, but not HALs. Bromine substitution factor (BSF) values of DBPs formed in chlorination decreased as specific ultraviolet absorbance (SUVA) increased. AOM favored the formation of iodinated THMs (I-THMs) during chloramination using preformed chloramines and chlorination-chloramination processes. Increasing prechlorination time can reduce the I-THM concentrations because of the conversion of iodide to iodate, but this increased the formation of chlorinated and brominated DBPs. In an analogous way, iodine substitution factor (ISF) values of I-THMs formed in chloramination decreased as SUVA values of DOM increased. Compared to chlorination, the formation of noniodinated DBPs is low in chloramination.     

生物过滤饮用水深度处理:机遇与挑战

源水水质的恶化给传统的饮用水处理工艺带来了挑战.生物过滤是饮用水消毒输配之前管理、维护及增强颗粒滤料表面生物活性以去除有机和无机物的过程.由于具有高效、低成本等优点，生物过滤在饮用水深度处理工艺中逐渐得到广泛的应用.本文综述了生物过滤在饮用水处理过程中对水中溶解性有机质（消毒副产物前体物）的去除、微量污染物的削减、嗅味化合物及氨氮的去除等.此外，针对生物过滤在水深度处理过程中存在的问题，本文详细讨论了含氮消毒副产物前体物的生成、低温下生物过滤效能下降等挑战，并提出了今后需要研究的问题.     

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.     

The impact of UV treatment on microbial control and DBPs formation in full-scale drinking water systems in northern China

To manage potential microbial risks and meet increasingly strict drinking water health standards, UV treatment has attracted increasing attention for use in drinking water systems in China. However, the effects of UV treatment on microbial control and disinfection by-products (DBPs) formation in real municipal drinking water systems are poorly understood. Here, we collected water samples from three real drinking water systems in Beijing and Tianjin to investigate the impacts of UV treatment on microbial control and DBP formation. We employed heterotrophic plate count (HPC), flow cytometry (FCM), quantitative PCR analysis, and high-throughput sequencing to measure microorganisms in the samples. Different trends were observed between HPC and total cell count (measured by FCM), indicating that a single indicator could not reflect the real degree of biological re-growth in drinking water distribution systems (DWDSs). A significant increase in the 16S rRNA gene concentration was observed when the UV system was stopped. Besides, the bacterial community composition was similar at the phylum level but differed markedly at the genera level among the three DWDSs. Some chlorine-resistant bacteria, including potential pathogens (e.g., Acinetobacter) showed a high relative abundance when the UV system was turned off. It can be concluded that UV treatment can mitigate microbial re-growth to some extent. Finally, UV treatment had a limited influence on the formation of DBPs, including trihalomethanes, haloacetic acids, and nitrogenated DBPs. The findings of this study may help to understand the performance of UV treatment in real drinking water systems.     

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.     

Synergistic cytotoxicity of binary combinations of inorganic and organic disinfection byproducts assessed by real-time cell analysis

Chlorine, chlorine dioxide, and ozone are widely used as disinfectants in drinking water treatments. However, the combined use of different disinfectants can result in the formation of various organic and inorganic disinfection byproducts (DBPs). The toxic interactions, including synergism, addition, and antagonism, among the complex DBPs are still unclear. In this study, we established and verified a real-time cell analysis (RTCA) method for cytotoxicity measurement on Chinese hamster ovary (CHO) cell. Using this convenient and accurate method, we assessed the cytotoxicity of a series of binary combinations consisting of one of the 3 inorganic DBPs (chlorite, chlorate, and bromate) and one of the 32 regulated and emerging organic DBPs. The combination index (CI) of each combination was calculated and evaluated by isobolographic analysis to reflect the toxic interactions. The results confirmed the synergistic effect on cytotoxicity in the binary combinations consisting of chlorite and one of the 5 organic DBPs (2 iodinated DBPs (I-DBPs) and 3 brominated DBPs (Br-DBPs)), chlorate and one of the 4 organic DBPs (3 aromatic DBPs and dibromoacetonitrile), and bromate and one of the 3 organic DBPs (2 I-DBPs and dibromoacetic acid). The possible synergism mechanism of organic DBPs on the inorganic ones may be attributed to the influence of organic DBPs on cell membrane and cell antioxidant system. This study revealed the toxic interactions among organic and inorganic DBPs, and emphasized the latent adverse outcomes in the combined use of different disinfectants.     

Evaluation of N-acetylcysteine and glutathione as quenching agents for the analysis of halogenated disinfection by-products

Disinfection by-products(DBPs), formed from the reactions of disinfectants with natural organic matter and halides in drinking water, were considered to be cytotoxic and genotoxic, and might trigger various cancers. The relatively low concentration of DBPs in finished water(low μg/L or even ng/L levels) and the interference from water matrix inhibited in situ determination of DBPs. Moreover, the further formation and degradation of DBPs by disinfectants during the holding time(several hours to s...