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1.
Owing to its low cost, free chlorine is one of the most common disinfectants for wastewater and drinking water treatment. However, the formation of disinfection byproducts has been found to occur after free chlorine disinfection in recent decades. Antipyrine (ANT), an anti-inflammatory analgesic, has been frequently detected in the aquatic environment. In this work, the removal efficiency of ANT by free chlorine oxidation in ultrapure water was investigated with batch experiments. The influencing factors on the removal of ANT were explored at initial concentrations of ANT from 0.04 to 0.64 mg/L, free chlorine dosage from 0.30 to 1.31 mg/L, and pH from 1.5 to 9.0. The main degradation products were identified by solid phase extraction-gas chromatography-mass spectrometry. The results showed that ANT reacted rapidly with free chlorine in ultrapure water systems and up to 90.6% removal efficiency of ANT was achieved after 25 sec (initial free chlorine 1 mg/L, ANT 0.5 mg/L, pH 7.0). Higher oxidant dosage, lower ANT initial concentration and low pH favor the ANT removal. The main degradation product in ANT chlorination was a monochlorine substitution product (4-chloro-1,2-dihydro- 1,5-dimethyl-2-phenyl-3H-pyrazol-3-one), which can be further chlorinated by free chlorine. In addition, the total organic carbon result indicated that ANT is difficult to be mineralized using chlorine.  相似文献   

2.
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 paper, a full-scale study of chlorine dioxide preoxidation cooperating with routine clarification process for Cyclops removal was conducted in a waterworks. The experimental results were compared with that of the existing prechlorination process in several aspects: including the Cyclops removal efficiencies of water samples taken from the outlets of sedimentation tank and sand filter and the security of drinking water and so on. The results showed that chlorine dioxide might be more effective to inactivate Cyclops than chlorine and Cyclops could be thoroughly removed from water by pre-dosing chlorine dioxide process. The GC-MS examination and Ames test further showed that the sort and amount of organic substance in the treated water by chlorine dioxide preoxidation were evidently less than that of prechlorination and the mutagenicity of drinking water treated by pre-dosing chlorine dioxide was substantially reduced compared with prechlorination.  相似文献   

3.
Modeling of residual chlorine in water distribution system   总被引:2,自引:0,他引:2  
Water quality within water distribution system may vary with both location and time.Water quality models are used to predict the spatial and temporal variation of water quality throughout water system.A model of residual chlorine decay in water pipe has been developed, given the consumption of chlorine in reactions with chemicals in bulk water,bio-films on pipe wall, in corrosion process, and the mass transport of chlorine from bulk water to pipe wall.Analytical methods of the flow path from water sources to the observed point and the water age of every observed node were proposed .Model is used to predict the decay of residual chlorine in an actual distribution system.Good agreement between calculated and measured values was obtained.  相似文献   

4.
A group parameter approach using "total organic halogen" is effective for monitoring gaseous organic halogen compounds, including fluorine, chlorine, and bromine compounds, generated from combustion. We described the use of barrier-discharge radiofrequency- helium-plasma/atomic emission spectrometry, for the detection of semi- and low-volatile organic halogen compounds (SLVOXs), which can be collected by Carbotrap TM adsorbents and analyzed using thermal desorption. The optimal carrier gas flow rates at the injection and desorption lines were established to be 100 mL/min. The detection range for SLVOXs in the gaseous samples was from 10 ng to tens of micrograms. Measuring F was more difficult than measuring Cl or Br, because the wavelength of F is close to that of air. The barrier- discharge radiofrequency-helium-plasma/atomic emission spectrometry measured from 85% to 103% of the SLVOXs in the gas sample. It has been found that Carbotrap B is appropriate for high-boiling-point compounds, and Carbotrap C is suitable for the determination of organic halogen compounds with lower boiling points, in the range 200-230°C. Under optimal analysis conditions, a chlorine- containing plastic was destroyed using different oxygen concentrations. Lower oxygen concentrations resulted in the production of lower amounts of organic halogen compounds.  相似文献   

5.
Biogas slurry is not suitable for liquid fertilizer due to its high amounts of volatile materials being of complicated composition and peculiar smell. In order to remove volatiles from biogas slurry efficiently, the dynamic headspace and gas chromatography-mass spectrometry were used to clear the composition of volatiles. Nitrogen stripping and superfluous ozone were also used to remove volatiles from biogas slurry. The results showed that there were 21 kinds of volatile compounds in the biogas slurry, including sulfur compounds, organic amines, benzene, halogen generation of hydrocarbons and alkanes, some of which had strong peculiar smell. The volatile compounds in biogas slurry can be removed with the rate of 53.0% by nitrogen stripping and with rate of 81.7% by the oxidization and stripping of the superfluous ozone. On this basis, the removal rate of the volatile compounds reached 99.2% by chloroform and n-hexane extraction, and almost all of odor was eliminated. The contents of some dissolved organic compounds decreased obviously and however main plant nutrients had no significant change in the biogas slurry after being treated.  相似文献   

6.
In this work, the contribution of mediated oxidation mechanisms in the electrolytic degradation of cyanuric acid using boron-doped diamond(BDD) anodes was investigated in different electrolytes. A complete mineralization of cyanuric acid was obtained in Na Cl;however lower degrees of mineralization of 70% and 40% were obtained in Na2SO4 and Na Cl O4, respectively. This can be explained by the nature of the oxidants electrogenerated in each electrolyte. It is clear that the contribution of active chlorine(Cl2, HCl O, Cl O-)electrogenerated from oxidation of chlorides on BDD is much more important in the electrolytic degradation of cyanuric acid than the persulfate and hydroxyl radicals produced by electro-oxidation of sulfate and water on BDD anodes. This could be explained by the high affinity of active chlorine towards nitrogen compounds. No organic intermediates were detected during the electrolytic degradation of cyanuric acid in any the electrolytes, which can be explained by their immediate depletion by hydroxyl radicals produced on the BDD surface. Nitrates and ammonium were the final products of electrolytic degradation of cyanuric acid on BDD anodes in all electrolytes. In addition, small amounts of chloramines were formed in the chloride medium. Low current density(≤ 10 m A/cm2) and neutral medium(p H in the range 6–9) should be used for high efficiency electrolytic degradation and negligible formation of hazardous chlorate and perchlorate.  相似文献   

7.
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.  相似文献   

8.
The effects of free chlorine disinfection of tap water and wastewater effluents on the infectivity, gene integrity and surface antigens of rotaviruses were evaluated by a bench-scale chlorine disinfection experiments. Plaque assays, integrated cell culture-quantitative RT-PCR (ICC-RT-qPCR), RT-qPCR, and enzyme-linked immunosorbent assays (ELISA), respectively, were used to assess the influence of the disinfectant on virus infectivity as well as genetic and antigenic integrity of simian rotavirus SA11 as a surrogate for human rotaviruses. The ICC-RT-qPCR was able to detect rotaviruses survival from chlorine disinfection at chlorine dose up to 20 mg/L (60 min contact), which suggested a required chlorine dose of 5 folds (from 1 to 5 mg/L) higher than that indicated by the plaque assay to achieve 1.8 log10 reductions in tap water with 60 min exposing. The VP7 gene was more resistant than the infectivity and existed at chlorine dose up to 20 mg/L (60 min contact), while the antigencity was undetectable with chlorine dose more than 5 mg/L (60 min contact). The water quality also impacted the inactivation efficiencies, and rotaviruses have a relatively higher resistant in secondary effluents than in the tap water under the same chlorine disinfection treatments. This study indicated that rotaviruses have a higher infectivity, gene and antigencity resistance to chlorine than that previously indicated by plaque assay only, which seemed to underestimate the resistance of rotaviruses to chlorine and the risk of rotaviruses in environments. Present results also suggested that re-evaluation of resistance of other waterborne viruses after disinfections by more sensitive infectivity detection method (such as ICC-RT-qPCR) may be necessary, to determine the adequate disinfectant doses required for the inactivation of waterborne viruses.  相似文献   

9.
Influences of organic matters of soil and water on speciation and biological utilization of selenium are discussed. Humic acid is found to be the main pool of selenium in soil and affects the bio-availability of the element in soil-plant system. Fulvic acid from drinking water inhibits the absorption of selenium taken from diet. The relationship between high content of organic matters of water and selenium deficiency on the causes of KBD could be reflected in the limited synthesis of glutathione peroxidase, which is generally stimulated by fulvic acid from drinking water.  相似文献   

10.
This study investigated the partitioning behavior of dissolved organic matter(DOM) in liquid and ice phases, as well as the changes in the optical properties and chlorine reactivity of DOM during the freezing processes of water. DOM was rejected from the ice phase and accumulated in the remaining liquid phase during water freezing. Moreover, the decrease in freezing temperature, as well as the increase in dissolved organic carbon(DOC)concentration of feed water, caused an increase in DOM captured in the ice phase. The ultraviolet-absorbing compounds, trihalomethane precursors, as well as fulvic acid- and humic acid-like fluorescent materials, were more liable to be to be rejected from the ice phase and were more easily retained in the unfrozen liquid phase during water freezing, as compared with organics(on average) that comprise DOC. In addition, it was also found a higher accumulation of these organics in the unfrozen liquid phase during water freezing at higher temperature. The freeze/thaw processes altered the quantity, optical properties, and chlorine reactivity of DOM. The decrease in ultraviolet light at 254 nm as well as the production of aromatic protein- and soluble microbial byproduct-like fluorescent materials in DOM due to freeze/thaw were consistently observed. On the other hand, the changes in DOC, trihalomethane formation potential, and fulvic acid- and humic acid-like fluorescence caused by freeze/thaw varied significantly between samples.  相似文献   

11.
辽河干流消落区沉积物重金属污染特征研究   总被引:4,自引:0,他引:4       下载免费PDF全文
刘强  梁雷  王峰源  刘峰 《中国环境科学》2013,33(12):2220-2227
通过测定辽河干流消落区10个断面中0~5cm、5~15cm、15~30cm深沉积物中重金属Pb、Cu、Zn、Cd含量,揭示消落区干-湿交替下沉积物重金属的污染特征.采用原子吸收分光光度计测定重金属含量,并采用地质累积指数与潜在生态危害指数评估重金属污染状况.结果表明,除Cd外,Cu、Zn与Pb的含量均值分别为31.4mg/kg、28.14mg/kg、43.75mg/kg,均低于中国土壤环境质量标准I级土壤标准;Cd含量均值1.438mg/kg,是中国土壤环境质量标准I级土壤标准的7.19倍,是辽河水系沉积物平均值的1.29倍,辽宁省土壤背景值的13.31倍,表明研究区Cd污染严重.地质累积指数评价表明,Pb、Cu、Zn的污染程度低于1级,Cd达2级中度污染以上,在通江口达3.92,为5级强污染;据潜在生态危害评价,达牛渡口上游干流潜在生态危害指数为强以上,通江口生态危害指数最高,且生态危害主要来源于Cd.相关性分析表明,Pb、Cu与Zn间相关性极显著,可能有相同的污染源,Cd有单独的污染源.  相似文献   

12.
将红鲫(Carassius auratus)分别暴露于0.5mg·L-1四滇双酚-A(TBBPA)和0.1 mg·L-1五澳酚(PBP)中28 d,采用放射性免疫分析法和化学发光酶联免疫分析法检测红鲫的血清甲状腺激素水平和肝脏脱碘酶活性.结果显示,TBBPA能使红鲫血清TT4和TT3水平降低,rT3水平、肝脏脱碘酶ID2和ID3活性升高.PBP对红鲫甲状腺系统的干扰要小于TBBPA,它对红鲫血清TT3水平和ID2活性几乎没有影响.上述结果表明,TBBPA和PBP能够干扰红鲫体内甲状腺激素的稳态,加速甲状腺激素在肝脏内的转化和代谢;这可能是通过抑制甲状腺激素与运载蛋白的结合来实现的.  相似文献   

13.
油田采出水膜法处理技术应用研究进展   总被引:2,自引:0,他引:2  
油田采出水的处理回用是一种必然的趋势.膜法处理技术可以解决传统水处理中存在的问题,有效地去除采出水中的油类、细菌、硬度,防止油层堵塞、结垢和外排水的环境污染,对于促进油气田可持续发展、水资源再利用和环境保护具有非常重要的意义.微滤、超滤和纳滤、反渗透膜技术在油田采出水处理中已有较多的应用研究.超滤在除油和除浊方面表现出...  相似文献   

14.
采用“物化+生物处理+深度处理”组合工艺处理垃圾焚烧厂渗滤液,探索组合工艺对渗滤液的实际去除效果,考察渗滤液中溶解性有机物(DOM)的组成及其结构特性随组合工艺的变化规律,并对其机理进行了初步探讨.结果表明,当进水COD和氨氮的平均值分别为17825,1946mg/L时,组合工艺对渗滤液中COD和氨氮去除率均达到99%左右,出水COD、氨氮、色度分别为57mg/L、5mg/L、15倍.组合工艺对渗滤液DOM中腐殖酸(HA)、富里酸(FA)和亲水性有机物(HyI)的去除率均达到99%左右,对HA、FA、HyI削减显著的工艺单元分别为混凝2、厌氧和颗粒活性炭(GAC),削减率分别达到86%、77%和84%.出水HA、FA和HyI的COD浓度分别为10,23,6mg/L,其中分子量较小的FA为出水主要组分.随着组合工艺处理过程的进行,渗滤液中DOM的紫外区吸光度值显著下降,DOM的E254、E253/E203分别由1.55、0.64下降至0.012和0.024,说明DOM的芳香性和复杂程度显著降低,脂肪链芳香化合物逐渐增加;此外,E300/E400和E465/E665分别由2.65和2.17增加至9.78和8.03,表明渗滤液中溶解性有机物腐殖化程度不断降低,芳香构化程度不断减小.  相似文献   

15.
DOM对纳滤膜去除磺胺甲恶唑效果影响研究   总被引:2,自引:1,他引:1       下载免费PDF全文
试验研究几种不同可溶性有机物(DOM)对纳滤膜(NF)去除抗生素磺胺甲恶唑(SMZ)的影响效果.试验所用DOM选定腐殖酸(HA)、单宁酸(TA)和海藻酸钠(SA).结果显示3种DOM对SMZ去除率和通量影响迥异,并与DOM的亲疏水性有密切的关系.为更好了解DOM对NF去除SMZ的影响机理,试验对臭氧化HA也进行了研究.臭氧化HA相对于臭氧前HA亲水性显著提高,对SMZ去除率的影响相应提高.结果表明在有多种DOM共同存在的天然原水中,SMZ的去除机理十分复杂,DOM的本身物理化学性质对于目标物的去除效果十分重要.  相似文献   

16.
为了探究磷(P)对小麦幼苗镉(Cd)和砷(As)吸收转运生理机制的影响,通过水培试验,以百农207为供试材料,研究了Cd和As胁迫条件下,外源供P和缺P处理对小麦幼苗生长、根系形态、光合参数、抗氧化系统、离子含量和根茎转移系数的影响.结果表明,与缺P处理相比,外源P供应显著增加As胁迫下小麦幼苗叶绿素的含量,促进根系的生长发育,提高了生物量,而对Cd胁迫下小麦幼苗的生长影响不显著.外源P供应时显著增加了Cd胁迫条件下根系的P和Cd含量,降低了地上部的P和Cd含量;同时显著提高了As胁迫条件下地上部的P和As含量以及As向地上部的转移系数.因此,供P与否对小麦幼苗Cd和As毒害的影响表现出明显的差异性;As胁迫时,外源供P提高了As向地上部的转运能力以及根系的CAT活性,降低了As对小麦的毒害,从而促进了小麦幼苗生物量的累积;而在Cd胁迫条件下,P与Cd之间表现出一定的协同效应,外源供P在一定程度上加重了Cd对小麦的毒害效应.  相似文献   

17.
四氯乙烯胁迫对草鱼抗氧化酶活性的影响及其机理   总被引:1,自引:0,他引:1  
研究了四氯乙烯(PCE)对草鱼的肝胰脏、肾脏和鳃组织的超氧化物歧化酶(SOD)和过氧化物酶(POD)的影响.结果表明:草鱼肝胰脏SOD活性,在PCE低浓度胁迫时其SOD活性“先升后降”[72h SOD是(6665.84±106.87)U/g·FW,168h SOD是(3021.26±16.96)U/g·FW],高浓度胁迫时“先降后升再降”[24h SOD是(2175.16±185.14)U/g·FW, 96h SOD是(5692.19±44.17)U/g·FW,168h SOD是(1297.70±11.52)U/g·FW];草鱼肾脏SOD活性在PCE所有浓度组胁迫均是“先降后升再降”的趋势;草鱼鳃组织SOD酶活性只有在PCE较低浓度短时间内没有显著变化,其它情况始终降低.在PCE低浓度和中等浓度胁迫时,草鱼肝胰脏POD活性始终降低,较低浓度和高浓度胁迫时肝胰脏POD活性“先降后升再降”;草鱼肾脏POD活性在PCE低浓度胁迫时“先升后降再升又降”的趋势,而高浓度胁迫时“先降后升又降”;PCE对草鱼鳃组织POD活性“先升后降”的趋势.但是草鱼鳃组织的SOD和POD活性明显低于肝胰脏和肾脏组织的SOD和POD活性.  相似文献   

18.
聚烃基烷酸转化对强化生物除磷影响研究   总被引:4,自引:5,他引:4  
刘燕  行智强  陈银广  周琪 《环境科学》2006,27(6):1103-1106
通过丙酸和乙酸C-mol比为0.5和2的合成废水驯化微生物的SBR反应器(SBR1和SBR2)批式实验,研究了强化生物除磷系统中聚烃基丁酸(PHB)和聚烃基戊酸(PHV)的转化对磷吸收/释放及去除率的影响.结果显示,磷的释放/吸收和去除率与PHB和PHV的转化有很好的相关性(R2>0.90).回归系数表明,特定废水驯化的污泥,磷的吸收和释放主要受PHB转化的影响,但磷的去除率却主要依赖于PHV的合成与降解;对于不同比例丙酸/乙酸废水驯化污泥,SBR2比SBR1污泥的PHB合成和降解能力增强,PHV合成和降解能力减小,生物除磷效果平均增加16.69%.因此,进水丙酸/乙酸比例及驯化影响聚磷微生物的PHB/PHV转化量,进而影响对磷的吸收/释放和除磷效果,PHB与PHV的转化量应作为生物除磷系统的关键调控因素考虑.  相似文献   

19.
以昆明小鼠为受试动物,随机分为6组,包括1个阴性对照组、3个氯氰菊酯染毒组、1个维生素E组和1个高剂量氯氰菊酯加维生素E组,染毒组按10,20,40mg/kg 3个剂量水平,维生素E的剂量为100mg/kg,灌胃染毒小鼠7d.以脑组织匀浆测定活性氧(ROS)、还原型谷胱甘肽(GSH)和丙二醛(MDA)的含量;以脑组织细胞测定DNA-蛋白质交联(DPC)系数.随着氯氰菊酯染毒剂量的升高,脑组织的ROS、MDA含量和DPC系数逐渐上升,GSH含量逐渐降低,各指标呈一定的剂量-效应关系.染毒剂量320mg/kg时,ROS含量(841.3±100.34)、GSH含量[(12.54±1.316)nmol/L]和DPC系数(0.054±0.004)有显著差异(P<0.05);染毒剂量340mg/kg时,GSH含量[(10.51±1.545)nmol/L]有显著差异(P<0.05),ROS含量(1014.3±81.67)、MDA含量[(2.849±0.218)μmol/L]和DPC系数(0.079±0.005)有极显著差异(P<0.01).高剂量染毒加维生素E组与高剂量染毒组相比较,脑组织的ROS、MDA含量和DPC系数均有下降,GSH含量上升.脑组织的ROS(719.5±74.56)、GSH[(16.52±1.985)nmol/L]和DPC系数(0.055±0.005)有显著差异(P<0.05),MDA含量[(1.662±0.265)μmol/L]有极显著差异(P<0.01).较高剂量(320mg/kg)的氯氰菊酯能造成小鼠脑组织的氧化损伤,维生素E有抗氧化作用.  相似文献   

20.
采用超声辅助分散液液微萃取结合气相色谱(UAE-DLLME-GC-ECD)检测了污泥中6种氯苯化合物.用丙酮作为萃取污泥样品中氯苯的萃取剂,通过改变萃取剂类型和用量、超声时间以及离子强度等影响因子的实验,确定了最优条件的关键性控制参数.结果表明,6种氯苯的相关系数r2=0.9993~0.9999,相对标准偏差RSD=3.2%~4.4%,检测限LOD为0.001~0.2μg/kg,对造纸、印染和市政3种污泥样品检测的回收率分别为89.2%~103.8%,94.5%~112.1%和89.1%~104.3%.该方法检测污泥中的氯苯不仅具有快速、灵敏和重复性好的特点,而且相对于传统方法,可以节省大量对人体有毒害作用的有机溶剂和分析时间.  相似文献   

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