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.     

Monitoring and modeling of disinfection by-products (DBPs)

In the United States, the newly promulgateddisinfectant/disinfection by-product (D/DBP) regulationsforce water treatment utilities to be more concerned withfinished and distributed water qualities. In this study,monitoring of DBP formation was conducted from three Frenchwater treatment plants trying to assess DBP variationsthrough time and space. Compared to the in-plant totaltrihalomethanes (TTHM) levels, TTHM levels in thedistribution system increased from less than 150% to morethan 300%. Significant variations for TTHM and bromate(BrO₃ ^-) levels throughout the seasons were alsoobserved; generally higher levels in the summer and lowerlevels in the winter. Combining chemical DBP models(empirical power functional models) and hydraulicsimulations, DBPs including TTHM and BrO₃ ^- weresuccessfully simulated from the full-scale monitoring data,indicating that empirical DBP model can be a potential toolto access DBP formation in actual plants. This study alsoprovides the protocols to assess DBP simulations in thewater treatment systems.     

Cu2+在混凝中对富里酸氯化消毒副产物的影响

混凝实验采用硫酸铝作为混凝剂,以富里酸（FA）为目标物,考察Cu²⁺对浊度、溶解性有机碳（DOC）去除效果和氯化消毒副产物生成势（DBPsFP）的影响,并采用三维荧光光谱（3DEEM）和超滤膜分级对混凝出水进行表征.结果表明,Cu²⁺可以通过络合反应提高混凝过程对FA中亲水性组分和芳香结构DBPs前驱体的去除效果.在pH> 7时,可以使二氯乙酸生成势（DCAAFP）和三氯甲烷生成势（TCMFP）明显降低.Cu²⁺-混凝的作用更倾向于影响FA中分子量级分处于10~30kDa的物质,提高其对DOC和DBPs生成势的去除效果.     

砷和二氯乙酰胺联合暴露下斑马鱼脏器富集及毒性的性别二态性研究

砷（As）是全球性毒害污染物,可与消毒副产物共存于水环境中,但目前缺乏两者对水生生物的系统联合毒性效应评估数据.本研究选用毒性较强的含氮消毒副产物—二氯乙酰胺（DCAcAm）为代表,研究其与无机三价As在不同性别成年斑马鱼肝脏、肠道、脑和鳃等器官中的联合毒性效应.结果表明,100 μg·L^-1 As和300 μg·L^-1 DCAcAm单一和联合暴露主要累积于肝脏,并在肝脏诱导最强的氧化损伤及炎症反应.As单一暴露对雌性斑马鱼表现出更强毒性,而DCAcAm单一暴露则在雄性斑马鱼中诱导更强毒性,两者的联合毒性效应在两种性别斑马鱼肝脏中均减弱.在雄性斑马鱼肠道、脑和鳃中,As和DCAcAm的毒性效应相互独立;而在雌性斑马鱼脑和鳃中联合毒性减弱,肠道中联合毒性增强.本研究结果可为As和DCAcAm联合毒性评估及健康风险评价提供数据支撑,对DCAcAm暴露的性别二态性响应的首次表征,可为DBPs类污染毒性效应评估提供另一维度的参考数据.     

消毒副产物中的氯原子对其分子描述符的影响

分析消毒副产物中氯原子数对分子描述符 ,辛醇 /水分配系数 Log P、最低空轨道能量 L UMO、前线轨道能量 HOMO、HO-MO-LUMO(ΔE)以及偶极矩的影响 .结果表明不同种类化合物对不同分子描述符的影响是不同的 ,其中以 Log P和 LUMO对氯原子数的相关性较好 ,HOMO次之 ,ΔE和偶极矩最差 .     

不同的消毒方式对砂滤池出水消毒效果的影响

采用中置O3-BAC工艺进行中试实验,通过对微生物、微型生物、消毒副产物和AOC进行检测分析,研究了不同的消毒方式对砂滤池出水消毒效果的影响。结果表明,氯消毒对微型生物、微生物的去除效果稍弱于臭氧联合氯消毒;对于消毒副产物而言,氯消毒产生的卤代烃、氯酸盐的含量高于臭氧联合氯消毒,产生的溴酸盐两者处于同一水平,而产生的甲醛则是氯消毒低于臭氧联合氯消毒;氯消毒最终砂滤池出水AOC平均含量75.93μg乙酸碳/L,臭氧联合氯消毒为101.23μg乙酸碳/L,大于100μg乙酸碳/L,不利于供水管网的生物稳定性。     

Impact of chlorine exposure time on disinfection byproduct formation in the presence of iopamidol and natural organic matter during chloramination

Chloramines,in practice,are formed onsite by adding ammonia to chlorinated drinking water to achieve the required disinfection.While regulated disinfection byproducts(DBPs)are reduced during chloramine disinfection,other DBPs such as iodinated(iodo-)DBPs,that elicit greater toxicity are formed.The objective of this study was to investigate the impact of prechlorination time on the formation of both halogen-specific total organic halogen(TOX)and iodo/chlorinated(chloro-)DBPs during prechlorination/chloramination in source waters(SWs)containing iopamidol,an X-ray contrast medium.Barberton SW(BSW)and Cleveland SW(CSW)containing iopamidol were prechlorinated for 5–60 min and afterwards chloraminated for 72 hr with ammonium chloride.Chlorine contact time(CCT)did not significantly impact total organic iodine(TOI)concentrations after prechlorination or chloramination.Concentrations of total organic chlorine(TOCl)formed during prechlorination did not significantly change regardless of pH and prechlorination time,whileTOClappearedtodecreaseafter 72 hrchloraminationperiod.Dichloroiodomethane(CHCl_2I)formation during prechlorination did not exhibit any significant trends as a function of p H or CCT,but after chloramination,significant increases were observed at pHs 6.5 and 7.5 with respect to CCT.Iodo-HAAs were not formed during prechlorination but were detected after chloramination.Significant quantities of chloroform(CHCl_3)and trichloroacetic acid(TCAA)were formed during prechlorination but formation ceased upon ammonia addition.Therefore,prechlorination studies should measure TOX and DBP concentrations prior to ammonia addition to obtain data regarding the initial conditions.     

蓝藻AOM特征与DBPs生成关系的研究进展

蓝藻水华期间,藻细胞因自然生长或受水处理工艺影响(如预氧化和混凝),会向水中释放大量藻源有机物(AOM),能够与氯消毒剂反应生成大量消毒副产物(DBPs),增加了饮用水安全风险.了解AOM的特征及其对DBPs生成的影响对于AOM的控制和饮用水安全保障至关重要.本文综述了蓝藻AOM的主要理化特征(溶解性有机碳、溶解性有机...     

再生水中消毒副产物——卤乙酸的测定方法研究

参照美国国家环保局(USEPA)推荐的饮用水卤乙酸类消毒副产物测定方法(Method 552.3),通过优化该方法的预处理条件和改变检测方法,提出了酸化萃取-衍生化-中和萃取-GC-MS测定再生水中卤乙酸含量的分析方法,并分析了北方某市再生水中4种卤乙酸类消毒副产物含量。结果表明,该方法适用于我国再生水水质,能够有效地消除再生水中共存污染物的干扰;其相对标准偏差(n=7)小于10%,方法的精密度较好;检出限与USEPA方法基本一致;样品加标回收率满足USEPA 6251B标准方法中(100±30)%要求;再生水中的卤乙酸比自来水高出几十倍,对环境和人类存在一定的潜在危害。     

The effects of pH, bromide and nitrite on halonitromethane and trihalomethane formation from amino acids and amino sugars

In this study, the effects of pH, bromide and nitrite on the formation of halonitromethanes (HNMs) and trihalomethanes (THMs) from eight amino acids (glycine, alanine, serine, cysteine, aspartic acid, glutamic acid, lysine and histidine) and four amino sugars (glucosamine, galactosamine, N-acetylglucosamine and N-acetylneuraminic acid) were examined for chlorination and ozonation followed by chlorination. During ozonation-chlorination, two amino acids, glycine and lysine, exhibited distinctly higher HNM formation than the other compounds. The formation of HNMs was higher at pH 8 than 6. Glycine and lysine also produced higher levels of THMs than the other compounds at pH 8. The presence of nitrite resulted in an increase in HNM formation. The presence of bromide increased the HNM formation, especially brominated HNM species. Bromine incorporation factors of trihalogenated HNMs were higher than those of THMs. For chlorination alone, HNM levels were about the detection limit (4 nM or 0.7 μg L⁻¹) at pH 6 and 8, and in the presence of bromide or nitrite. Amino acids and amino sugars tested, except glycine and lysine, showed relatively low levels of THM (∼15 μg L⁻¹) formation.