首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
为研究UV/US(Ultraviolet/Ultrasonic,紫外/超声)协同对水中隐孢子虫的灭活机制,采用UV灯(功率为14 W)与US发生器(频率为20 kHz,功率为150 W)组合装置协同灭活隐孢子虫,考察pH、温度、浊度和HA(腐殖酸)对UV/US协同灭活隐孢子虫的影响,并通过SEM(扫描电镜)、蛋白质试验和琼脂糖凝胶电泳检测对灭活机制进行了探讨.结果表明:pH对UV/US杀灭隐孢子虫的影响不大,碱性条件下灭活率略高于中性和酸性条件;温度对灭活率有一定影响,5℃下灭活率较低,随温度的上升,灭活率逐渐提高,25℃下10 min灭活率可达99%以上;悬浮物抑制隐孢子虫的灭活,浊度为40 NTU时,UV/US作用25 min的灭活率仅为93.88%;HA对灭活的影响表现为低浓度促进,高浓度抑制;ρ(HA)高于10 mg/L时,继续增大ρ(HA)对隐孢子虫灭活率影响不大.研究显示:UV/US协同作用对隐孢子虫的灭活机制主要是使其卵囊破裂,同时损伤了隐孢子虫胞内的DNA.   相似文献   

2.
二氧化氯灭活水中隐孢子虫的影响因素及机理研究   总被引:2,自引:0,他引:2       下载免费PDF全文
以荧光活体染色法研究了ClO2浓度、灭活时间、浊度、pH值、温度、有机物含量等,对ClO2灭活隐孢子虫效果的影响,并利用扫描电镜和蛋白质实验初步探究了灭活机理.结果显示,当pH7.0,水温为25℃,浊度为1NTU时,投加3mg/L ClO2经过120min,可以达到最适消毒效果(存活率小于1%),隐孢子虫的灭活率与ClO2投加浓度、作用时间成非线性正相关.浊度是影响ClO2灭活隐孢子虫的主要因素,浊度越低,灭活效果越佳;水温(较)低,灭活效果稍差;酸性较于碱性更适宜ClO2灭活隐孢子虫;可溶性有机物一定程度上影响ClO2的灭活效果.扫描电镜和蛋白试验表明,ClO2主要破坏其细胞表面结构,从而引起隐孢子虫死亡.  相似文献   

3.
氯气灭活饮用水中隐孢子虫的影响因素   总被引:1,自引:1,他引:0       下载免费PDF全文
应用荧光活体染色法研究Cl2在水体中杀灭隐孢子虫的效果,并探讨投加量、作用时间、浑浊度、pH值、温度、有机物含量等对Cl2灭活隐孢子虫效果的影响规律,找出最佳投加量和作用时间.结果显示,隐孢子虫浓度1×106个/mL,温度22℃,pH7.0,浊度为1.0NTU,氯气投加量大于6.3mg/L,反应时间360min,隐孢子虫的灭活率可以达到预期灭活效果(灭活率﹥99.0%).隐孢子虫的灭活率与氯气投加量和作用时间成正相关;灭活率随着浑浊度增加逐渐下降,浑浊度0.1~20.0NTU范围内,氯气投加量为6.3mg/L,作用时间大于900min,即可保证隐孢子虫的灭活率符合预定要求;在弱酸性条件下氯气灭活隐孢子虫能力强于碱性条件,反应温度(5.0~35.0℃)范围内,隐孢子虫的灭活率与温度成正相关;HA浓度0~10.0mg/L,作用时间为360min时,灭活率随有机物浓度增加而降低.当作用时间为900min时,水中隐孢子虫的灭活率均大于99.0%.  相似文献   

4.
为高效去除饮用水中腐殖酸,研究以腐殖酸配水为研究对象,聚合氯化铝(PAC)为絮凝剂,沸石粉为助凝剂,着重考察了PAC与沸石粉单独及两者联合使用时对腐殖酸溶液的去除效能,结果表明:PAC可有效降低腐殖酸的浓度,在1 L水样中,当PAC投量为110 mg/L时,腐殖酸去除率达到89.13%,出水浊度为0.176NTU;对于PAC混凝而言,沸石粉的投加起到吸附、助凝、助沉、除浊的混凝效果,当沸石粉投量为5 mg/L,PAC投量降至40 mg/L时,出水浊度由1.75 NTU降至0.333 NTU,腐殖酸去除率由26.16%提高至84.38%,沸石粉通过助凝作用,可以显著地改善PAC混凝对腐殖酸的去除效能,同时亦可有效减少PAC的投加量。  相似文献   

5.
以深圳市发生水华的某景观湖水为研究对象,研究过氧化氢(H2O2)与硫酸铜(以Cu2+计)组合投加对水样藻类生物量的控制效果及对水样溶解氧、pH、浊度的影响。结果表明:组合投药能显著抑制藻类生长,在处理第7天,组合投药A组(20 mg/L H2O2+0.2 mg/L Cu2+)、B组(10 mg/L H2O2+0.4 mg/L Cu2+)、C组(5 mg/L H2O2+0.8 mg/L Cu2+)的Chl a浓度分别降至对照组的58%、30%、18%。投加过氧化氢有助于增强硫酸铜的抑藻效果,A组Chl a浓度在第1天降至49μg/L,显著低于单独投加0.2 mg/L Cu2+的处理组(81μg/L)。投加过氧化氢有助于降低Cu2+投加量,B组抑藻效果与单独投加0.6 mg/L Cu2+处理组第7天数值相同。组合投药使水样溶解氧、pH值、浊度均显著变化,第7天时,溶解氧由17.5 mg/L降至8.7~13.3 mg/L,pH值由10.0降至8.5~9.2,浊度由200 NTU降至84~94 NTU。  相似文献   

6.
采用Fe/C微电解-Fenton氧化联合工艺处理某固体废弃物处理企业填埋区的垃圾渗滤液,以降低其COD与浊度值,并去除渗滤液中的重金属离子。结果表明:当pH=4~5,铁炭复合材料投加量为30~40 g/L,曝气量为40 L/min,水力停留时间(HRT)为1 h时,微电解方法对垃圾渗滤液中的Ni2+、Cr(Ⅵ)、Pb2+的去除效果较好,其去除率分别达到 96%、97%和96%,垃圾渗滤液色度去除率为92.41%,COD去除率为62.33%,浊度由40.73NTU降至3.09 NTU,COD由579.2 mg/L降至218.16 mg/L。对微电解工艺出水进一步采用Fenton氧化工艺处理,结果表明:当Fe2+浓度为0.007 mol/L,氧化时间为90 min,n(H2O2):n(Fe2+)=1.2:1条件下,COD去除率为67.50%,浊度为53.20%,处理后的出水浊度为1.47 NTU、COD为69.49 mg/L,达到GB 18918-2002《城镇污水处理厂污染物排放标准》的二级排放标准。  相似文献   

7.
为研究超声对饮用水中隐孢子虫(Cryptosporidium parvum)的灭活情况,考察了超声频率、功率、pH值和温度对灭活率的影响,通过形态学观察初步探讨了超声灭活隐孢子虫的机制,并进行了灭活动力学分析.结果表明,低频有利于隐孢子虫灭活,19.8kHz,pH7.2,温度(20±1)℃条件下超声15min灭活率可达92.5%,频率升高灭活率反而下降.在本实验条件下,超声功率103W对隐孢子虫的灭活效果与151W的相近,pH值对超声灭活隐孢子虫的影响不大,36℃超声灭活15min灭活率为95.6%,而在9℃下超声15min灭活率为88.3%,水温升高有利于灭活.灭活前后的形态学变化表明超声空化作用导致细胞膜破坏,细胞质流出从而起到灭活孢囊的效果.超声灭活隐孢子虫遵循假一级反应动力学,灭活隐孢子虫以低频率高功率的效果最好,可认为隐孢子虫的灭活以超声空化的强度为主.  相似文献   

8.
为研究超声对饮用水中隐孢子虫(Cryptosporidium parvum)的灭活情况,考察了超声频率、功率、pH值和温度对灭活率的影响,通过形态学观察初步探讨了超声灭活隐孢子虫的机制,并进行了灭活动力学分析.结果表明,低频有利于隐孢子虫灭活,19.8kHz, pH7.2,温度(20±1)℃条件下超声15min灭活率可达92.5%,频率升高灭活率反而下降.在本实验条件下,超声功率103W对隐孢子虫的灭活效果与151W的相近,pH值对超声灭活隐孢子虫的影响不大,36℃超声灭活15min灭活率为95.6%,而在9℃下超声15min灭活率为88.3%,水温升高有利于灭活.灭活前后的形态学变化表明超声空化作用导致细胞膜破坏,细胞质流出从而起到灭活孢囊的效果.超声灭活隐孢子虫遵循假一级反应动力学,灭活隐孢子虫以低频率高功率的效果最好,可认为隐孢子虫的灭活以超声空化的强度为主.  相似文献   

9.
臭氧-紫外预处理对高有机物原水混凝效果的影响   总被引:7,自引:6,他引:1       下载免费PDF全文
以腐殖酸为模型污染物,分别考察了臭氧氧化、紫外照射及臭氧-紫外联合预处理过程对高有机物原水混凝性能的影响.结果表明,3种预处理方式均对原水中的溶解性腐殖酸具有明显的矿化作用.紫外及臭氧-紫外联合预处理还对后续的混凝过程具有强化作用.随着臭氧投量的增加和紫外照射时间的延长,混凝过滤出水的TOC和浊度呈明显下降趋势.当臭氧浓度(O3/C)达到9.0 mg/mg时,预处理对腐殖酸的去除率可以达到47%,过滤出水TOC含量为3.5 mg/L,浊度为2.6 NTU;紫外光照射3 h可去除原水中52%的溶解性有机物,其出水TOC为2.0 mg/L,浊度低于1.0 NTU.臭氧-紫外联合预处理后的混凝效果要明显优于二者单独作用的系统.在联合预处理系统中,当预臭氧浓度(O3/C)为1.0 mg/mg紫外照射时间为1 h时,过滤出水TOC为2.6 mg/L,且浊度低于1.0 NTU.不同预处理条件下的矿化作用主要是通过.OH实现的,同时.OH还对溶解性腐殖酸的团聚结构产生破坏作用,使其稳定性降低,从而促进了混凝过程对有机物的去除.  相似文献   

10.
为研究O3在水体中杀灭贾第虫的效果,利用荧光活体染色法探讨了不同因素(CT值、pH值、温度、浊度、有机物含量和无机离子等)对O3灭活贾第虫效果的影响.结果表明,O3灭活贾第虫整个过程可分为指数和缓慢灭活期,指数灭活期反应速度明显快于缓慢灭活期[k1=(5.64±0.023)×10-1mg·min,k2=(2.72±0.002)×10-2mg·min,k1k2];浊度0.1~20NTU,温度5~35℃,pH值6.0~9.0,HA在0.5~10.0mg/L浓度范围内,浊度越低,灭活效果越好;随温度上升,O3灭活贾第虫的能力减弱;酸性较碱性条件下臭氧杀灭贾第虫的能力更强;有机物浓度越高,在反应体系中与贾第虫发生了竞争作用,降低了灭活率;水中阴离子对灭活率的影响次序为:NO3-NoneSO24-HCO3-,而阳离子(Ca2+、Mg2+和Cu2+)均对灭活起到一定促进作用;当臭氧CT值≥15.0min·mg/L,在饮用水消毒的浊度、温度、pH值、有机和无机杂质浓度范围内,贾第虫的灭活率均在99.0%以上.  相似文献   

11.
Several main metabolites of benzo[a]pyrene (BaP) formed by Penicillium chrysogenum, Benzo[a]pyrene-1,6-quinone (BP 1,6- quinone), trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene (BP 7,8-diol), 3-hydroxybenzo[a]pyrene (3-OHBP), were identified by high-performance liquid chromatography (HPLC). The three metabolites were liable to be accumulated and were hardly further metabolized because of their toxicity to microorganisms. However, their further degradation was essential for the complete degradation of BaP. To enhance their degradation, two methods, degradation by coupling Penicillium chrysogenum with KMnO4 and degradation only by Penicillium chrysogenum, were compared; Meanwhile, the parameters of degradation in the superior method were optimized. The results showed that (1) the method of coupling Penicillium chrysogenum with KMnO4 was better and was the first method to be used in the degradation of BaP and its metabolites; (2) the metabolite, BP 1,6-quinone was the most liable to be accumulated in pure cultures; (3) the effect of degradation was the best when the concentration of KMnO4 in the cultures was 0.01% (w/v), concentration of the three compounds was 5 mg/L and pH was 6.2. Based on the experimental results, a novel concept with regard to the bioremediation of BaP-contaminated environment was discussed, considering the influence on environmental toxicity of the accumulated metabolites.  相似文献   

12.
Sorption of chlorotoluron in ammonium sulfate, urea and atrazine multi-solutes system was investigated by batch experiments. The results showed application of nitrogen fertilizers to the soil could affect the behavior of chlorotoluron. At the same concentration of N, sorption of chlorotoluron decreased as the concentration of atrazine increased on the day 0 and 6 in soil, respectively. The sorption of chlorotoluron increased from 0 to 6 d when soils were preincubated with deionized water, ammonium sulfate and urea solution for 6 d. That indicated incubation time was one of the most important factors for the sorption of chlorotoluron in nitrogen fertilizers treatments. The individual sorption isotherms of chlorotoluron in rubbery polymer and silica were strictly linear in single solute system, but there were competition sorption between pesticides or between pesticides and nitrogen fertilizers. That indicated the sorption taken place by concurrent solid-phase dissolution mechanism and sorption on the interface of water-organic matter or water-mineral matter.  相似文献   

13.
Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis (DGGE) and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity (both in gene richness and diversity index values) and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor (50 mg/kg) recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos (150 mg/kg) caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos (250 mg/kg) produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes (bands) responded differently to the impact of agrochemicals: four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.  相似文献   

14.
The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.  相似文献   

15.
Earthworm toxicity tests are useful tools for terrestrial risk assessment but require a hierarchy of test designs that differ in effect levels (behavior, sublethal, lethal). In this study, the toxicity of chlorpyrifos contaminated soil on earthworms was assessed. In addition to the acute and chronic tests, an avoidance response test was applied. Earthworms were exposed to sublethal and lethal concentration of chlorpyrifos, and evaluated for acute toxicity, growth, fecundity and avoidance response after a certain exposure period. The test methods covered all important ecological relevant endpoints (acute, chronic, behavioral). Concentration of 78.91 mg/kg, chlorpyrifos caused significant toxic effects in all test methods, but at lower test concentrations, only significant chronic toxic effects could be observed. In the present study, chlorpyrifos had adverse effect on growth and fecundity in earthworm exposed to 5 mg/kg chlorpyrifos after eight weeks. The avoidance response test, however, showed significant repellent effects concentration of 40 mg/kg chlorpyrifos. For chlorpyrifos, concentration affecting avoidance response was far greater than growth and fecundity, it seemed likely that earthworms were not able to escape from pesticide-contaminated soil into the clean soil in field and hence were exposed continuously to elevated concentrations of pesticides.  相似文献   

16.
Bottled water may not be safer, or healthier, than tap water. The present studies have proved that styrene and some other aromatic compounds leach continuously from polystyrene (PS) bottles used locally for packaging. Water sapmles in contact with PS were extracted by a preconcentration technique called as "purge and trap" and analysed by gas chromatograph-mass spectrometer (GC/MS). Eleven aromatic compounds were identified in these studies. Maximum concentration of styrene in PS bottles was 29.5 μg/L. Apart from styrene, ethyl benzene, toluene and benzene were also quantified but their concentrations were much less than WHO guide line values. All other compounds were in traces. Quality of plastic and storage time were the major factor in leaching of styrene. Concentration of styrene was increased to 69.53 μg/L after one-year storage. In Styrofoam and PS cups studies, hot water was found to be contaminated with styrene and other aromatic compounds. It was observed that temperature played a major role in the leaching of styrene monomer from Styrofoam cups. Paper cups were found to be safe for hot drinks.  相似文献   

17.
In this study an effort has been made to use plant polyphenol oxidases; potato (Solanum tuberosum) and brinjal (Solanum melongena), for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.  相似文献   

18.
The potential harm of heavy metals is a primary concern in application of sludge to the agricultural land. A pot experiment was conducted to evaluate the effect of two sludges on fractionation of Zn and Cu in soil and their phytotoxicity to pakchoi. The loamy soil was mixed with 0%, 20%, 40%, 60% and 80% (by weight) of digested sewage sludge (SS) and composted sludge (SC). The additions of both sludges caused a significant raise in all fractions, resulting in that exchangeable (EXCH) and organic bound (OM) became predominance of Zn and organic bound Cu occupied the largest portion. There was more available amount of Zn and Cu in SS treatments than SC treatments. During the pot experiment, the concentration of Zn in EXCH, carbonate (CAR) and OM and Cu in EXCH and OM fractions decreased in all treatments, so their bioavailability reduced. Germination rate and plant biomass decreased when the addition rate was high and the best yield appeared in 20% mixtures at the harvest of pakchoi. The two sludges increased tissue contents of Zn and Cu especially in the SS treatments. Zn in pakchoi was not only in relationship to ΔEXCH and ΔCAR forms but also in ΔOM forms in the sludge-soil mixtures. Tissue content of Cu in pakchoi grown on SC-soils could not be predicted by ΔEXCH. These correlation rates between Zn and Cu accumulation in pakchoi and variation of different fractions increased with time, which might indicate that sludges represented stronger impacts on the plant in long-term land application.  相似文献   

19.
A hydroponic experiment was carried out to study intraspecific differences in the effects of different concentrations of cadmium (Cd)(0-10 mg/L) and arsenate (As(V)) (0-8 mg/L) on the growth parameters and accumulation of Cd and As in six wheat varieties Jing-9428, Duokang-1, Jingdong-11, Jing-411, Jingdong-8 and Zhongmai-8. The endpoints of wheat seedlings, including seed germination,biomass, root length and shoot height, decreased with increasing the Cd and As concentrations. Significant differences in seed germination, biomass, root length, shoot height and the accumulation of Cd and As were observed between the treatments and among the varieties (p < 0.05). The lethal dosage 50% were about 20, 80, 60, 60, 80 and 20 mg As/L for Jing-9428, Duokang-1, Jingdong-11,Jing-411, Jingdong-8 and Zhongmai-8, respectively, and the corresponding values for Cd were about 30, 80, 20, 40, 60 and 10 mg Cd/L, respectively. Among the six varieties, Duokang-1 was found to be the most resistant to Cd and As toxicity, and Zhongmai-8 was the most sensitive to Cd and As co-contamination. The resistance of the six varieties was found dependant on the seedling uptake of Cd and As. Duokang-1 was the most suitable for cultivation in Cd and As co-contaminated soils.  相似文献   

20.
UNITANK is a biological wastewater treatment process that combines the advantages of traditional activated sludge process and sequencing batch reactor, which is divided into Tank A, B and C. In this study, the sludge distribution and its impact on performance of UNITANK were carried out in Liede Wastewater Plant (WWTP) of Guangzhou, China. Results showed that there was a strong affiliation between Tank A and B of the system in sludge concentration distribution. The initial sludge concentration in Tank A could present the sludge distribution of the whole system. The sludge distribution was mainly influenced by hydraulic condition. Unsteady sludge distribution had an impact on variations of substrates in reactors, especially in decisive reactor, and this could lead to failure of system. Settler could partially remove substrates such as COD and NO3-N, but there was adventure of sludge deterioration. The rational initial sludge concentration in Tank A should be 4000-6000 mg/L MLSS.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号