Reactions Between Humic Acid Solutions and Excessive ClO_2 or Cl_2

Reactions between humic acid solutions and excessive ClO2 or Cl2 have been investigated. Under various experimental conditions, the removal efficiency of TOC, UV254and A410 from humic acid solutions were examined. The relationship between the removal efficiency and the consumption of ClO2 or Cl2 was discussed. The results showed that the maximum demand of ClO2 was 2.19 mg/mg TOC for the humic acid solution under the experimental conditions, and that of ClO2 was 1.88 mg/mg TOC. The variation tendency of ClO2 consumption was similar to that of Cl2. TOC of humic acid solutions decreased 15.2% and 15.6% after the reaction with ClO2 or Cl2 respectively. Under the experimental conditions, 21.4% of unsaturated bonds and 52.8% of humic acid color were removed by ClO2 in 168 h. As for Cl2, removal efficiency of unsaturated bonds and humic acid color were 16.8% and 41.7% respectively. Larger molecules from humic acid were oxidized to smaller molecules by ClO2 and Cl2. Higher oxidation potential of ClO2 than that of Cl2 was also indicated by variation of UV254/A410 ratios. The similar tendency, that exhibited faster variation in the initial 24 h, existed for all the research factors.

化学法生产ClO_2及其在饮用水处理中的应用

主要介绍了化学法生产ClO2 的原理 ,及其在饮用水消毒中的系统设计、运行情况和使用效果。

Treatment of taste and odor causing compounds 2-methyl isoborneol and geosmin in drinking water:A critical review

Problems due to the taste and odor in drinking water are common in treatment facilities around the world. Taste and odor are perceived by the public as the primary indicators of the safely and acceptability of drinking water and are mainly caused by the presence of two semi-volatile compounds - 2-methyl isobomeol （MIB） and geosmin. A review of these two taste and odor causing compounds in drinking water is presented. The sources for the formation of these compounds in water are discussed alongwith the health and regulatory implications. The recent developments in the analysis of MIB/geosmin in water which have allowed for rapid measurements in the nanogram per liter concentrations are also discussed. This review focuses on the relevant treatment alternatives, that are described in detail with emphasis on their respective advantages and problems associated with their implementation in a full- scale facility. Conventional treatment processes in water treatment plants, such as coagulation, sedimentation and chlorination have been found to be ineffective for removal of M1B/geosmin. Studies have shown powdered activated carbon, ozonation and biofiltration to be effective in treatment of these two compounds. Although some of these technologies are more effective and show more promise than the others, much work remains to be done to optimize these technologies so that they can be retrofitted or installed with minimal impact on the overall operation and effectiveness of the treatment system.

Occurrence of odor problems in drinking water of major cities across China

A comprehensive investigation into the occur-rence of odor problem at 111 drinking water treatment plants （DWTPs） in major cities across China was undertaken using both flavor profile analysis （FPA） and gas chromatography-mass spectrometry （GC-MS）. Eighty percent of source water samples exhibited odor problems, characterized by earthy/musty （41%） and swampy/septic （36%） odors, while the occurrence rate was lower （45%） in the finished water. Source water from rivers exhibited more pollution-origin odors, such as the swampy/septic odor, while that from lakes and reservoirs exhibited more algae- origin odors, such as earthy/musty odors. The occurrence rate of 2-methylisoborneol （2-MIB） in the surface source water samples was 75%, with 7% of samples containing 2- MIB concentrations of over 10 ng.L-1. The earthy/musty odor in the lake/reservoir water samples was mainly caused by 2-MIB （linear regression coefficient, R2= 0.69）, while the correlation between 2-MIB concentration and the earthy/musty odor intensity samples was weak （R2= 0.35） in the river-source water These results will be useful for the management of odor-quality problems in drinking water of China.

Mechanism and kinetics of 2-chlorophenol degradation in drinking water by photo-electrochemical synergic effect

The synergic effect mechanism of photo-electrochemical oxidation is investigated in detail through reaction products and kinetics analysis in a photo-electric integral reactor with 2-chlorophenol (2-CP) as the model pollutant. A kinetics model is constructed for the combinatorial photo-electrochemical (CPE) degradation. A remarkable synergetic effect, which can significantly enhance the mineralization rate of the CPE process, is verified by the comparison of apparent kinetic constants. In the CPE process, complemental effects with multi-level and multi-pathway for pollutants degradation under our experimental conditions are speculated. It is proved that the degradation pathways are not only the simple summation of that of photolysis and electrolysis, but the formation of synergic effect through combination of several new acting approaches. The degradation efficiency is enhanced considerably by three factors, control of electrode poisoning by the UV irradiation, control of excitation and reaction trend of pollutants molecules by the UV irradiation, and control of activation effect and transfer trend by the oriented direct current (DC) electric field. An advanced oxidation system is set up through manifold of free radicals chain reactions in the CPE reactions, so that the aqueous organics can be mineralized fast and completely. It is proven by the kinetics analysis that the mineralization of organic pollutants is mainly attributed to the generation of very active hydroxyl radicals (OH@) in bulk solution from the CPE synergetic effect.

Responses of bacterial strains isolated from drinking water environments to N-acyI-L-homoserine lactones and their analogs during biofilm formation

Often as a result ofbiofilm formation, drinking water distribution systems （DWDS） are regularly faced with the problem of microbial contamination. Quorum sensing （QS） systems play a marked role in the regulation of microbial biofilm formation; thus, inhibition of QS systems may provide a promising approach to biofilm formation control in DWDS. In the present study, 22 bacterial strains were isolated from drinking water-related environments. The following properties of the strains were investigated： bacterial biofilm formation capacity, QS signal molecule N-acyl-L-homoserine lactones （AHLs） production ability, and responses to AHLs and AHL analogs, 3-chloro-4-（dichloromethyl）-5-hydroxy-2（5H）- furanone （MX） and 2（5H）-furanone. Four AHLs were added to developed biofilms at dosages ranging from 0.1 nmol.L J to 100nmol.L1. As a result, the biofilm growth of more than 1/4 of the isolates, which included AHL producers and non-producers, were significantly promoted. Further, the biofilm biomasses were closely associated with respective AHLs concentrations. These results provided evidence to support the idea that AHLs play a definitive role in biofilm formation in many of the studied bacteria. Meanwhile, two AHLs analogs demon- strated unexpectedly minimal negative effects on biofilm formation. This suggested that, in order to find an applicable QS inhibition approach for biofilm control in DWDS, the testing and analysis of more analogs is needed.

Degradation of endocrine disruptor bisphenol A in drinking water by ozone oxidation

The ozone oxidation of endocrine disruptor bisphenol A in drinking water was investigated.A stainless completely mixed reactor was employed to carry out the degradation experiments by means of a batch model.With an initial concentration of 11.0 mg/L,the removal efficiencies of BPA(bisphenol A)could be measured up to 70%,82%,and 90%when the dosages of ozone were 1,1.5,and 2 mg/L,respectively.The impacts on BPA degradation under the con-ditions of different ozone dosages,water background values,BPA initial concentrations,and ozone adding time were ana-lyzed.The results showed that ozone dosage plays a dominant role during the process of BPA degradation,while the impact of the contact time could be ignored.UV wavelength scan-ning was used to confirm that the by-products were produced,which could be absorbed at UV254.The value of UV254 was observed to have changed during the ozonation process.Based on the change of UV254,it could be concluded that BPA is not completely degraded at low ozone dosage,while shorter adding time of total ozone dosage,high ozone dosage,and improvement of dissolved ozone concentration greatly contribute to the extent of BPA degradation.The effects of applied H_(2)O_(2) dose in ozone oxidation of BPA were also examined in this study.The O_(3)-H_(2)O_(2) processes proved to have similar effects on the degradation of BPA by ozone oxidation.

模拟太阳光/ClO_(2)高级氧化技术降解卡马西平及其水环境适用性

基于ClO_(2)光解的高级氧化技术在微污染物去除方面得到了广泛研究,一般通过ClO_(2)光解产生的活性物种(Cl·、ClO·、^(1)O_(2)、O_(3)和HO·等)来实现水体中目标污染物的降解.抗癫痫药卡马西平(CBZ)难以被生物降解和自然光降解,在水环境中具有持久性.该文系统研究了模拟太阳光/ClO_(2)体系中活性物种对CBZ去除效率及降解路径的影响,同时评估了水基质(如pH的变化及Cl^(-)、HCO_(3)^(-)、腐殖酸和富里酸等的存在)对污染物降解效率的影响.研究结果表明^(1)O_(2)、O_(3)和HO·等在CBZ降解过程中发挥重要作用,模拟太阳光/ClO_(2)体系中CBZ降解效率随着pH的增大而减小,Cl^(-)的存在对CBZ降解影响较小,HCO_(3)^(-)的存在不利于CBZ降解,天然有机质中的腐殖酸对CBZ降解的抑制作用要大于富里酸,水体中K^(+)、Ca^(2+)、Mg^(2+)等阳离子的存在不影响CBZ降解效率.

给水厂嗅味及溴化物复合微污染原水处理试验与工程应用

随着农村城市化、农业工业化的推进,水环境受到了污染。针对水的浑浊度、菌类仅采用混凝、沉淀、过滤、消毒工艺的水厂不能大幅度降低水中溶解杂质,不可避免地引起了自来水水质变化。以山东省新泰市Q水厂为例,自2010年开始,水库水源水因网箱养鱼和支流河道污水汇入,导致藻类繁殖,高锰酸盐指数(COD_(Mn))、氨氮等污染物含量增加,水质恶化。藻类破裂释放的微囊藻毒素和放线菌代谢产生的土臭素(geosmin,GSM)、2-甲基异莰醇(2-methylisoborneol,2-MIB)严重影响了饮用水供水水质。根据微污染杂质的主要成分、变化规律及产生的环境因素、生物因素等,特对强化常规处理法、物理吸附法、化学氧化法、生物降解等微污染水源水处理方法进行比较分析。认为采用臭氧(O_(3))氧化还原能有效氧化藻致嗅化合物和微囊藻毒素。考虑到当地水源水中含有溴化物的特点,选用O_(3)氧化和生物活性炭(BAC)过滤联用较为合理。经对Q水厂出厂水试验,在水温为10℃左右、O_(3)投加量≤2.0 mg/L、BAC滤池空床接触时间为12 min,具有去除CODMn50%、氨氮40%以上、溴酸盐≤0.01 mg/L的效果。按此工艺实施Q水厂升级改造工程,实现了出厂水水质稳定达标。通过对O_(3)-BAC工艺的处理效能持续监测和低温条件下的强化处理运行管控研究发现:低温季节,气水冲洗活性炭滤层摩擦剧烈,生物膜脱落,增殖缓慢,降低生物氧化降解作用,除污染效果变差。调整冲洗方式后,改善了这一现象;选用水并联、O_(3)化氧气串联的完全混合连续式反应器(CSTR)溶解臭氧化气体,增大气、水接触面积和气体浓度差、加快液膜紊动更新,和通用的水串联、O_(3)化气体并联的鼓泡式反应器相比,极大提高了O_(3)化气体溶解度。理论计算,制水成本减少了44.63%。

离子色谱法检测饮用水中NaClO_(2)和KClO_(3)的优化应用

本文优化离子色谱法,用于检测饮用水中的NaClO_(2)和KClO_(3)。结果表明,自来水中NaClO_(2)和KClO_(3)的浓度最高,井水次之,瓶装水最低,表明水源处理方式对消毒副产物的生成量有直接影响;优化后的离子色谱法明显提高了检测灵敏度、检测精度,而且重复性良好,适用于检测水样中痕量存在的消毒副产物。

在线超滤-离子色谱法同时测定生活饮用水5种消毒副产物

为了同时测定生活饮用水中的5种消毒副产物DCAA,TCAA,ClO_(2)^(-),BrO_(3)^(-)和ClO_(3)^(-)的含量,旨在构建一种高效便捷的在线超滤-离子色谱法。通过使用Metrohm metrosep a supp18-250型色谱柱,淋洗液结合浓度为14 mmol/L NaOH淋洗液,流速0.6 mL/min,以及质量分数为1%H_(2)SO_(4)抑制器再生液,运用英蓝在线超滤技术,可有效地对生活饮用水中的三氯乙酸(CCl_(3)COO^(-))(TCAA)、二氯乙酸(CHCl_(2)COO^(-))(DCAA)、亚氯酸盐(ClO_(2)^(-))、氯酸盐(ClO_(3)^(-))、溴酸盐(BrO_(3)^(-))进行分离检测,且同时进行其方法线性、准确度、精密度、检出限、定量限及加标回收率的检测。通过试验发现,标准曲线相关系数远高于0.995,相对标准偏差不超过3%。此外,加标回收率介于96.7%~102.7%,在37 min内,就能够完成5种生活水体中的消毒副产物的分析,每个物质组分检测灵敏度极高,检测周期极短,分析效率很高,因此适用于大规模的生活饮用水的测试。

吹扫捕集-GC-MS/MS法测定饮用水中2-甲基异莰醇和土臭素

目的利用吹扫捕集—气相色谱串联质谱(GC-MS/MS)法测定生活饮用水中2-甲基异莰醇和土臭素的分析方法。方法取5 mL水样,以高纯氮气会载气在40 mL/min流速下吹扫11 min后,热解吸进入GC-MS/MS进行分析,以2-异丁基-3-甲氧基吡嗪为内标进行定量。结果在优化的实验条件下,2-甲基异莰醇和土臭素在5.0~100 ng/L浓度范围内线性较好,相关线性系数(R^(2))分别为0.9996和0.9998,方法检出限分别为0.13 ng/L和0.06 ng/L,水样加标回收率在92.3%~104.5%之间,相对标准偏差(RSD)为1.89%~4.07%。结论该方法简便、快速、准确、灵敏度高,可用于测定饮用水中2-甲基异莰醇和土臭素。

TiO_(2)光催化技术在蓝藻代谢物处理中的应用

TiO_(2)光催化技术能有效降解蓝藻毒素、异嗅物质等蓝藻代谢物,提升饮用水水质。实际水源中蓝藻代谢物种类复杂,而现有研究主要集中在TiO_(2)光催化技术对微囊藻毒素的处理上,对于其他常见蓝藻代谢物的处理效果缺乏系统的对比分析。因此,基于常见蓝藻毒素与异嗅物质的毒性和特点,分析了不同TiO_(2)光催化技术对水中蓝藻毒素、异嗅物质以及藻细胞-藻毒素复合污染物的降解效果,并探讨了TiO_(2)光催化除藻技术在水厂应用的可行性。

原位产H_(2)O_(2)催化臭氧饮用水深度处理中试

近年来,高品质供水受到广泛关注,而单一技术对污染物的深度处理效果有限。因此,文中以河北省某水厂高密度沉淀池出水为研究对象,首先构建了以电催化臭氧-生物活性炭(electro-peroxone-biological activated carbon,EP-BAC)为主体工艺的饮用水深度处理中试装置,探究了其对常规指标包括CODMn、UV254的去除效果,确定了最优运行条件。此外,对优化后的系统稳定运行效果进行研究,关注了系统对嗅味物质2-甲基异莰醇(2-MIB)的去除能力,并分析了系统的经济性。结果表明,EP-BAC中试系统具有很好的深度处理效果,最佳运行条件:进水流量为2 m^(3)/h,水温为20~25℃,氧化停留时间为30 min,BAC接触时间为40 min,H_(2)O_(2)质量浓度为1 mg/L,O_(3)质量浓度为1.5 mg/L,O_(3)与H_(2)O_(2)摩尔比为1∶1。经30 d持续运行测试,系统可以有效、稳定地运行。通过测算,该系统吨水运行成本为0.93元。整个工艺无二次污染产生,绿色安全,工程应用将具有明显的性能优势。

不同填料对滤池处理嗅味物质2-MIB的中试研究

针对水厂常规工艺对2022年发布的《生活饮用水卫生标准》中新增感官性指标2-MIB去除效果欠佳问题,以柱状滤池为实验装置,通过填充不同滤料模拟不同水厂滤池运行,对不同水厂生物滤池及砂滤料处理2-MIB效果、影响因素进行中试研究,在检验去除2-MIB的同时,对装置出水的浊度、UV254、硝酸盐等指标与滤池出水对比。结果表明,水厂滤池的生物滤料在其它水厂仍可发挥处理2-MIB效果,通过砂滤料与生物炭滤料混合,可以使原本不具有2-MIB降解效果的砂滤池出水2-MIB浓度低至10 ng/L以下,且其浊度、UV254去除效果与水厂常规滤池一致。同时滤池进水余氯量是影响出水2-MIB的重要因素,余氯量越高,出水2-MIB浓度随之升高。本实验为不具有去除2-MIB效果滤池且无深度处理工艺的水厂,提供了一种见效快、成本低的2-MIB处理方法,可以在不影响水厂滤池正常运行,不需增加深度处理工艺条件下,实现高效去除2-MIB。

南方水体中的2-甲基异莰醇和土臭素检测方法优化

在《生活饮用水标准检验方法第8部分:有机物指标》(GB/T 5750.8—2023)的基础上,优化了一种使用气相色谱-质谱联用仪(GC-MS)测定生活饮用水中2-甲基异莰醇(2-MIB)和土臭素(GSM)的方法。经优化后,避免了国标法检测复杂水样时可能出现杂峰影响致嗅物质定量分析的现象。同时,将连续进样的检测时间缩短至31 min。以2-异丁基-3-甲氧基吡嗪(IBMP)为内标,2-MIB、GSM在0~60 ng/L线性良好,相关系数r为0.9995~0.9997;检出限为0.08~0.28 ng/L;定量限为0.27~0.93 ng/L。两种物质在3种不同浓度的精密度测试中的相对标准偏差(RSD)为4.90%~8.06%;在质控样测试中RSD为2.68%~5.20%,偏差为0.7%~12.3%;在3种不同浓度的下的加标回收率为85.7%~114%。

饮用水中典型致嗅物质去除技术研究

为去除某市饮用水中的嗅味,根据该市饮用水水源中致嗅物质的组成特点,采用氧化、吸附和臭氧活性炭对其中典型致嗅物质的去除效果及工艺选择进行了研究.结果表明,硫醇硫醚类物质可以用氧化法有效去除,对土嗅素(geosmin)和2-甲基异莰醇(2-MIB)采用氧化法和活性炭吸附法均有效,但吸附法的效果更好;当原水中硫醇、硫醚类致嗅物质浓度<20μg/L,不含有其他类型致嗅物质时,可以采用强化混凝+高锰酸钾氧化工艺去除;当原水中geosmin、2-MIB等微生物代谢产物类致嗅物质浓度<30 ng/L,不含有硫醇硫醚类致嗅物质时,可以采用强化混凝+粉末活性炭吸附工艺去除;当原水中硫醇、硫醚类致嗅物质浓度>20μg/L,geosmin、2-MIB浓度>30 ng/L时,需要增加臭氧活性炭深度处理工艺;当原水中硫醇、硫醚类致嗅物质浓度>150μg/L,或者土嗅素、2-MIB的浓度>100 ng/L时,需要根据致嗅物质组成特点,选择预KMnO4氧化或者粉末活性炭吸附+臭氧活性炭深度处理的组合工艺去除.

上海市饮用水中痕量土臭素和二甲基异冰片年变化规律及来源研究

采用液液微萃取-气相色谱/质谱联用测定饮用水中痕量异嗅物质——土臭素（geosmin,GSM）和二甲基异冰片（2-Methylisoborneol,2-MIB或MIB）.对上海市饮用水水源以及某水厂工艺出水进行调查发现,土霉味的来源主要为2-MIB,异嗅问题暴发季节为7-10月,7、8月份达到顶峰,原水中2-MIB的最高检出浓度可达152.82 ng/L,水厂出水中最高检出浓度为97.94 ng/L.初步的来源分析推断2-MIB为水中颤藻的代谢产物.

臭氧氧化分解饮用水中嗅味物质2-甲基异莰醇

比较了几种常见氧化剂对饮用水中嗅味物质2甲基异莰醇（2-methyli soborneol，MIB）的氧化去除效果．结果表明，KMn04、NaClO、H2O2等氧化剂的氧化作用对水中MIB的去除效果均较差，而臭氧却能有效地将其氧化；考察了pH对臭氧化去除MIB的影响规律，发现pH在7．0～10．0条件下，随着pH值增加MIB去除率增加，但当pH达到10．0左右时，MIB的去除率反而下降；MIB的臭氧化去除效果随着自由基捕获剂（重碳酸盐和叔丁醇）的浓度增加而明显地降低，说明臭氧化去除水中MIB主要遵循自由基作用机理；以松花江江水为本底进行试验和与蒸馏水进行试验的结果相差不大，原因可能是由于松花江水体中碳酸盐浓度较低（小于50mg／L），对自由基捕获能力较小，同时江水中的部分腐殖质（NOM）对臭氧去除MIB的过程起到了促进作用．

用纤维 TiO_2 作光催化剂降解饮用水中腐殖质

用纤维状ＴｉＯ２作为光催化剂，采用间歇和连续两种操作方式，在Ｏ３／ＴｉＯ２／ＵＶ体系中处理含腐殖质的饮用水，使腐殖质去除率达９７％，纤维ＴｉＯ２可过滤回收，易于实际应用。