Pilot-scale study of removal effect on Chironomid larvae with chlorine dioxide

Introduction C hironom id, from the dipteran fam ily Chirono- m idae, is a non-biting m idge that is w idely distributed in the northern hem isphere at tem perate latitudes. C hironom id larvae can be found both in lentic and lotic environm ents, usually …     

Removal effect on Mesocyclops leukarti and mutagenicity with chlorine dioxide

Introduction The eutrophication of surface water is a worldwide problem, which is increasing in significance (Ma and Liu, 2002). Mesocyclops leukarti, a kind of Cyclops, is a waterborne animal that excessively propagates in eutrophic reservoirs and fresh …     

Removal of benzene homologous compounds with chlorine dioxide

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高锰酸钾预氧化对剑水蚤DBPsFP的去除特征研究

以剑水蚤为试验对象,研究在不同条件下,高锰酸钾预氧化对剑水蚤代谢产物在氯化消毒过程中消毒副产物前体物的去除特征.研究表明:随高锰酸钾投加量的增加,水合氯醛(CH)、1,1,1-三氯丙酮(1,1,1-TCP)、三氯甲烷(TCM)总体呈上升趋势,二氯乙酸(DCAA)逐渐减少,而三氯硝基甲(TCNM)、1,1-二氯丙酮(1,1-DCP)、二氯乙腈(DCAN)和三氯乙酸(TCAA)先上升后下降,在本试验高锰酸钾投量范围内,高锰酸钾浓度为5mg/L时 CH、TCNM、DCAN、TCAN、DCAA、TCAA和1,1-DCP的去除效果最佳,去除率最高可达72.2%;延长预氧化时间,DCAN、DCAA、TCAA浓度逐渐降低,TCM、CH浓度逐渐升高,TCNM、TCAN、1,1,1-TCP浓度先升高后降低,而1,1-DCP浓度先迅速下降后逐渐升高,预氧化时间宜控制在20min;pH<7可有效抑制TCM的生成.pH=7时TCAA达到最小值,而1,1-DCP含量最高,pH>7有助于1,1-DCP的减少,CH、DCAA、DCAN、TCAN、TCNM和1,1,1-TCP随pH的增加而减少.在pH=9时生成量均最小, 最高去除率为80%;最佳温度为30℃,随着温度的升高,DCAA、TCAA和TCM浓度有所增加,1,1-DCP、DCAN和1,1,1-TCP生成量减少,在20℃时,CH的浓度最小,而TCAN的浓度最大.     

二氧化氯对剑水蚤类浮游动物的灭活与去除

进行了氯气和二氧化氯灭活剑水蚤的对比试验,并分析了pH值、有机物含量等对二氧化氯灭活剑水蚤的影响.在此基础上,对预氧化与混凝过程的协同除蚤效能进行了考察.结果表明,与氯气相比二氧化氯对剑水蚤具有更显著的灭活作用,在较低的投加量（1.0 mg/L）下,接触30 min就可以达到100％的灭活率.当水体pH值为5.7～8.0,灭活效果不受影响,但pH值为9.8可以导致灭活率降低10%.有机物含量对灭活率产生显著影响,有机物含量增加,则灭活率降低.混凝烧杯试验表明,二氧化氯投加量为0.9 mg/L时,二氧化氯预氧化与混凝沉淀的协同作用将完全去除原水中的剑水蚤.     

Kinetics of aniline oxidation with chlorine dioxide

For the first time, kinetics of aniline oxidation with chlorine dioxide(ClO2) were investigated systematically by detecting concentration of aniline with HPLC at regular intervals. Results showed that the reaction was first-order both in ClO2 and in aniline, and the oxidation reaction could be described as second-order reaction. Stoichiometric factor η was experimentally determined to be 2.44. The second-order-reaction rate constant k was 0.11L/(mol.s)under condition of pH 6.86 and water temperature(Tw) 287K. Reaction activation energy was 72.31 kJ/mol, indicating that the reaction could take place under usual water treatment conditions. The reaction rate constants in acidic and alkali media were greater than that in neutral medium. Chlorite ion could slightly increase reaction rate in acidic medium. p-aminophenol and azobenzene were detected by GC-MS as intermediates.     

二氧化氯对水源水中摇蚊幼虫灭活效果的研究

采用二氧化氯和液氯灭活蒸馏水中的第1龄期摇蚊幼虫, 在此基础上, 考察了人工配水和天然原水中二氧化氯对1龄摇蚊幼虫的灭活特征,探讨了原水温度和pH值对二氧化氯灭活1龄摇蚊幼虫的影响.结果表明,与液氯相比, 二氧化氯对1龄摇蚊幼虫具有更好的灭活作用,投加量1.5mg/L,接触30min可以达到100%的灭活率; pH值在5.5~8.1变化对二氧化氯的灭活效果不会产生影响;二氧化氯对1龄摇蚊幼虫的灭活率随TOC的增加而降低;在10~30℃,温度升高能够提高二氧化氯的灭活效果,当原水温度从30℃降低到15℃时灭活率下降为84.5%.     

Change in genotoxicity of wastewater during chlorine dioxide and chlorine disinfections and the influence of ammonia nitrogen

The effects of chlorine dioxide and chlorine disinfections on the genotoxicity of different biologically treated sewage wastewater samples were studied by umu-test. The experiment results showed that when chlorine dioxide dosage was increased from 0 to 30 mg/L, the genotoxicity of wastewater first decreased rapidly and then tended to be stable, while when the chlorine dosage was increased from 0 to 30 mg/L, the genotoxicity of wastewater changed diversely for different samples. It was then found that ammonia nitrogen did not affect the change of genotoxicity during chlorine dioxide disinfection of wastewater, while it greatly affected the change of genotoxicity during chlorine disinfection of wastewater. When the concentration of ammonia nitrogen was low (< 10–20 mg/L), the genotoxicity of wastewater decreased after chlorine disinfection, and when the concentration of ammonia nitrogen was high (> 10–20 mg/L), the genotoxicity of wastewater increased after chlorine disinfection.     

Control effects of pε and pH on the generation and stability of chlorine dioxide

IntroductionDuetotheformationofsomepotentiallyhazardousby productsfromchlorinedisinfectionindrinkingwater,chlorinedioxide(ClO2 ) ,asanalternativedisinfectantandaneffectiveoxidant,formedfewerhalogenatedDBPsthanchlorine(Richardson ,1 994;2 0 0 0 ;Bryant,1 992 ) .InvestigationsofthegenerationandstabilityofClO2 havealreadypromoteditsapplication .However,previousstudiespaynoattentiontothefactorofelectronactivity (pε)thatactuallyaffectsthegenerationandstabilityofClO2 Theignoranceofpεappearan…     

应用紫外/氯组合工艺去除微污染原水中氨氮的特性研究

针对饮用水中氨氮超标对环境造成的污染问题,采用紫外/氯组合工艺对饮用水中氨氮进行降解研究.结果表明,紫外/氯高级氧化工艺可以有效去除水中氨氮.一方面,自由氯和氨氮之间发生取代反应将氨氮转化为氯胺,254 nm紫外光可有效裂解N—Cl键,一氯胺在254 nm处的摩尔吸光系数为354 L·mol~(-1)·cm~(-1),量子产率为0.68 mol·E~(-1);另一方面,自由氯光解产生的自由基可直接氧化氨氮.随着紫外辐照剂量的增加,氨氮和总溶解性氮(TN)的浓度逐渐减少,当紫外辐照剂量达到1000 mJ·cm~(-2)时,氨氮(起始浓度2 mg·L~(-1))和TN的去除率分别为53%和35%,相比单独氯化条件下分别提高了20%和15%.随着Cl_2/N的增加,氨氮和TN的浓度逐渐减小,当Cl_2/N≥1.6时,紫外/氯组合工艺对氨氮的去除率接近100%,当Cl_2/N1.6时,紫外/氯工艺对TN的去除率相比单独氯化工艺提高了30%左右.此外,氨氮去除率随pH升高而增加,而TN去除率随pH升高而降低.本研究结果可为紫外/氯组合工艺在水厂中的实际应用提供有效的理论和技术支持.     

二氧化氯预氧化对三氯乙醛前体物的去除与机制研究

以我国南方某水源水为研究对象,研究不同二氧化氯投加量下三氯乙醛(CH)前体物的去除情况,并对其去除机制进行分析.结果表明:当二氧化氯投加量为0.4 mg·L~(-1)时,CH生成势(CHFP)去除率最高,为14.3%,同时比CH生成势(SCHFP)亦有大幅削减,且二氧化氯预氧化对浊度和SUVA_(254)亦有较好的去除效果,但对COD_(Mn)去除效果不明显,DOC、UV_(254)则有小幅上升.二氧化氯去除CH前体物的机制是通过将含C=C双键和C=O双键的不饱和芳香性蛋白质类及微生物代谢产物类亲水性物质氧化降解或转化为其他非CH前体物的物质,从而使CH的生成量减少.     

ClO2和碳水化合物水平对中国明对虾存活和生长的影响

研究了盐度为5条件下,ClO2和碳水化合物水平对中国明对虾(Fenneropenaeus chinensis)存活和生长的影响,共两个实验:实验1研究了ClO2(0、1、4、7、10、13、16、19和22 mg/L)对中国明对虾存活的影响,发现随ClO2浓度的升高,对虾存活率呈下降趋势;在24、48、72和96 h,LC50分别为21.04、13.32、10.91和8.26 mg/L,安全浓度为1.60 mg/L.实验2研究了ClO2(0.0、0.2、0.4和0.6 mg/L)和饲料中碳水化合物水平(13.89和41.76%)对中国明对虾存活和生长的影响,发现在两个碳水化合物水平,随ClO2浓度的升高,对虾存活率、特定生长率、摄食量和吸收效率均呈下降趋势,而饲料系数呈上升趋势;在四个ClO2水平,摄食13.89%碳水化合物对虾的特定生长率、摄食量和吸收效率均高于摄食41.76%碳水化合物的对虾,而摄食13.89%碳水化合物对虾的饲料系数低于摄食41.76%碳水化合物的对虾.     

Reversed flow injection spectrophotometric determination of low residuals of chlorine dioxide in water using chlorophenol red

A novel,simple,rapid,sensitive and highly selective flow injection procedure for the spectrophotometric determination of chlorine dioxide in the presence of othe chlorine species,viz,free chlorine,chlorite,chlorate and hypochlorite,is developed.The method is based on the discoloration reaction between chlorine dioxide and chlorophenol red and can overcome the shortcomings existed in direct spectrophotometric determination for chlorine dioxide owing to the serious interference of free and combined dhlorine.The procedure gave a linear calibration graph over the range0-0.71 mg/L of chlorine dioxide.With a detection limit of 0.024 mg/L and a sample throughput of 60 samples/h.     

二氧化氯消毒前后污水毒性的变化及消毒条件的影响

采用发光细菌试验和umu试验,分别考察了二氧化氯投加量和反应时间对污水二氧化氯消毒后急性毒性和遗传毒性变化的影响.结果表明,随着二氧化氯消毒剂投加量的增加,消毒后水样的急性毒性不断增大,但遗传毒性逐渐减小后趋于稳定.随着反应时间的延长,二氧化氯的消耗量不断增大,消毒后水样的急性毒性先增大后减小,遗传毒性逐渐减小后趋于稳定.由于消毒条件对污水急性毒性和遗传毒性有着不同的影响,说明污水中产生急性毒性和产生遗传毒性的物质不同,对于某一种污水,通过控制消毒条件可以使消毒后污水的急性毒性和遗传毒性都较低.     

几种消毒剂对饮水致突变活性的影响

本研究应用Ａｍｅｓ致突变试验对武汉东湖水分别经氯、二氧化氯和臭氧消毒处理后的致突变活性进行了检测与比较。结果表明：东湖水以及臭氧消毒处理水样未呈现致突变性,氯与二氧化氯处理的水样致突变性检测结果为阳性,这３种消毒剂处理的各水样致突变比活性强度顺序由强至弱依次为氯〉二氧化氯〉臭氧;同时对东湖水用高锰酸钾预处理,以降低氯化消毒饮水致突变活性的效果也进行了比较,结果发现用高锰酸钾预处理东湖水,可降低氯化     

Biological control experiment of excess propagation of Cyclops for drinking water security

Cyclops of zooplankton propagated excessively in eutrophic water body and could not be effectively inactivated by the conventional disinfections process like chlorination due to its stronger resistance to oxidation. In this study, an ecological project was put forward for the excess propagation control of Cyclops by stocking the filter-feeding fishes such as silver carp and bighead carp under the condition of no extraneous nutrient feeding. The results of experiments with different stocking biomass showed that the propagation of Cyclops could be controlled effectively, and the water quality was improved simultaneously by impacting on nutriment level and plankton community structure at proper stocking density of 30 g/m^3 of water. The growth of Cyclops may not be effectually controlled with lower biomass of fish （10 g）, and the natural food chain relation may be destroyed for Cyclops dying out in water while the intense stocking of 120 g per cubic meter of water. In addition, the high predator pressure may accelerate supplemental rate of nutrients from bottom sediments to water body to add the content of total nitrogen and phosphorus in water.     

环境友好消毒剂二氧化氯的灭活效果和消毒副产物

消毒是一个非常重要水处理单元过程,但常规消毒剂氯气会产生具有"三致"作用的消毒副产物.二氧化氯(ClO2)灭活效率高,消毒副产物的危害小,是一种环境友好消毒剂.总结了ClO2对水中细菌、病毒、乙肝表面抗原(HBsAg)、原生动物、浮游动物、藻类等的灭活效果,分析了温度、pH、CT(ClO2浓度×灭活时间)等对ClO2灭活水中微生物效果的影响,探讨了ClO2消毒过程中产生的副产物的性质,提出了相应的控制方法,展望了ClO2在水处理中的应用前景.     

Effects of low pH on zooplankton in some suburban waterbodies of Chongqing City

ＥｆｆｅｃｔｓｏｆｌｏｗｐＨｏｎｚｏｏｐｌａｎｋｔｏｎｉｎｓｏｍｅｓｕｂｕｒｂａｎｗａｔｅｒｂｏｄｉｅｓｏｆＣｈｏｎｇｑｉｎｇＣｉｔｙＺｈｕａｎｇＤｅｈｕｉ（ＩｎｓｔｉｔｕｔｅｏｆＨｙｄｒｏｂｉｏｌｏｇｙ，ＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎｃ...     

Characterization of halogenated DBPs and identification of new DBPs trihalomethanols in chlorine dioxide treated drinking water with multiple extractions

Chlorine dioxide(ClO_2) is a widely used alternative disinfectant due to its high biocidal efficiency and low-level formation of trihalomethanes and haloacetic acids. A major portion of total organic halogen(TOX), a collective parameter for all halogenated DBPs, formed in ClO_2-treated drinking water is still unknown. A commonly used pretreatment method for analyzing halogenated DBPs in drinking water is one-time liquid–liquid extraction(LLE), which may lead to a substantial loss of DBPs prior to analysis. In this study, characterization and identification of polar halogenated DBPs in a ClO_2-treated drinking water sample were conducted by pretreating the sample with multiple extractions. Compared to one-time LLE, the combined four-time LLEs improved the recovery of TOX by 2.3 times. The developmental toxicity of the drinking water sample pretreated with the combined four-time LLEs was 1.67 times higher than that pretreated with one-time LLE.With the aid of ultra-performance liquid chromatography/electrospray ionization-triple quadrupole mass spectrometry, a new group of polar halogenated DBPs, trihalomethanols,were detected in the drinking water sample pretreated with multiple extractions; two of them,trichloromethanol and bromodichloromethanol, were identified with synthesized standard compounds. Moreover, these trihalomethanols were found to be the transformation products of trihalomethanes formed during ClO_2disinfection. The results indicate that multiple LLEs can significantly improve extraction efficiencies of polar halogenated DBPs and is a better pretreatment method for characterizing and identifying new polar halogenated DBPs in drinking water.     

Evaluation of the adsorption potential of titanium dioxide nanoparticles for arsenic removal

The adsorption potential of titanium dioxide (TiO2) nanoparticles for removing arsenic from drinking water was evaluated. Pure and iron-doped TiO2 particles are synthesized via sol-gel method. The synthesized TiO2 nanoparticles were then immobilized on ordinary sand for adsorption studies. Adsorption isotherms were conducted on the synthesized nanoparticles as well as the sand coated with TiO2 nanoparticles under varying conditions of air and light, namely, the air-sunlight (A-SL), air-light (AL), air-dark (AD) and nitrogen-dark (ND). X-Ray diffraction (XRD) analysis showed that the pure and the iron-doped TiO2 nanoparticles were in 100% anatase crystalline phase with crystal sizes of 108 and 65 nm, respectively.Adsorption of arsenic on the three adsorbents was non-linear that could be described by the Freundlich and Langmuir adsorption models. Iron doping enhanced the adsorption capacity of TiO2 nanoparticle by arresting its grain growth and making it visible light responsive resulting in a higher affinity for arsenic. Similarly, the arsenic removal by adsorption on the sand coated with TiO2 nanoparticles was the highest among the three types of sand used. In all cases, As(V) adsorbed more compared with As(III). Solution pH appeared to be the most important factor in controlling the amount of arsenic adsorbed.