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1.
水生植物滤床(HFB)是一种用于净化富营养化水体的新型无基质型人工湿地系统。为考察HFB系统对水体中微囊藻毒素的处理效果,在太湖湖滨进行了中试研究。结果表明,在7—9月份,总藻毒素去除率在36.5%~75.8%之间,平均去除率为59.4%;胞外藻毒素平均去除率为50.0%;胞内藻毒素平均去除率为63.9%。不同植物组合型式的HFB系统对总藻毒素去除效果无显著差异。在水力负荷1.0~6.0m3/(m2·d)范围内,HFB系统去除藻毒素效果也无显著差异。系统对藻毒素的去除效果与富营养化指标(叶绿素-a、CODMn、TP)的处理效果成直线正相关性,藻毒素可作为一辅助指标从健康效应角度来反映富营养化水体水质改善情况。HFB系统在水源地藻毒素污染控制方面具有应用价值。  相似文献   

2.
中国及世界其他国家众多湖泊、水库、鱼塘等水体常发生不同程度的蓝藻水华。其中,微囊藻是一种最常见最受关注的水华蓝藻,它会产生一群结构相似且难以降解的肝毒素,即微囊藻毒素(Microcystins,MCs),对饮用水源水处理、水产品质量和生态系统健康都构成威胁。急需研发能有效控制突发性或常态化蓝藻水华和去除藻毒素的方法,将有毒蓝藻生物量与藻毒素浓度控制在安全限值以下,以确保饮用水与水产品质量安全。由此实际需求出发,研究者在控藻和除藻毒素这两方面分别开展了许多研究工作,并取得了显著的效果。研究方法主要有物理方法、化学方法、生物方法,但这些方法彼此较为独立。由于在控藻过程中常常导致更多的藻毒素释放到水中,在除藻毒素过程中藻细胞不停地增殖产生更多的藻毒素,故近些年人们逐渐意识到同时控藻和除藻毒素的重要性。只有同时去除藻细胞和藻毒素,才能从根本上解决蓝藻水华对水体污染的问题。文章综述了目前国内外可同时控藻和除藻毒素的方法,以期为蓝藻及藻毒素在水生生态环境中的预警和污染控制提供理论指导和技术支持。从物理方法、化学方法、生物方法和组合方法进行了分类。物理方法相对安全,但成本和能耗高。化学方法成效显著,但成本高且选择性较差。生物方法成本低,但去除速率慢。组合方法结合物理方法、化学方法、生物方法各自的优点,扬长避短,实现安全、高效、低成本、快速的控藻和除藻毒素。但是,目前的研究大多停留在实验室,将这些方法应用在野外,需要因地制宜,合理设计策略。  相似文献   

3.
微囊藻毒素对束丝藻细胞生长和抗氧化系统的影响   总被引:1,自引:0,他引:1  
为从活性氧(ROS)角度探讨微囊藻毒素(MC)导致藻类细胞死亡的机理及揭示藻细胞对MC诱发的氧化胁迫的响应机制,采用50和500μg·L-1的微囊藻毒素LR(MC-LR)处理束丝藻(Aphanizomenon sp. DC01)细胞,测定了细胞生长、细胞内活性氧(ROS)含量及抗氧化系统的变化.结果表明,50μg·L-1的MC-LR处理对藻细胞的生长无显著影响,而500μg·L-1的MC-LR处理可诱导藻细胞死亡.50μg·L-1的MC-LR处理的藻细胞ROS含量在处理第2d显著高于对照;但藻细胞能通过还原型谷胱甘肽(GSH)含量,超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GPX)活性改变修复氧化损伤,使ROS水平在处理第3d恢复到对照水平.500μg·L-1的MC-LR处理可显著降低藻细胞GSH含量和SOD与GPX活性,刺激藻细胞生成过量的ROS;ROS在毒素处理4d后突然暴发,过量的ROS引起膜质过氧化,并最终导致藻细胞死亡。  相似文献   

4.
一株溶藻细菌对铜绿微囊藻的溶藻机理初探   总被引:1,自引:0,他引:1  
罗固源  刘静  王金霞  叶姜瑜 《生态环境》2010,19(11):2647-2651
为确定溶藻细菌S7(Chryseobaterium)对铜绿微囊藻的溶藻方式,分别采用高温灭菌(121~123℃)、离心(10 000 r.min-1)、0.22μm滤膜过滤等方式对S7菌液进行处理,检测其对铜绿微囊藻的去除效果。并通过对溶藻过程中叶绿素a和丙二醛(MDA)含量的测定,藻细胞显微结构的观察和细胞成分的红外光谱分析,初步探讨菌株S7对铜绿微囊藻的作用机理。结果表明,S7是通过释放胞外活性物质间接溶藻,该物质具有很强的热稳定性,不属于蛋白质类物质。该活性物质对铜绿微囊藻的叶绿素a有明显的去除效果,并可导致藻细胞膜脂过氧化产物MDA积累量的显著提高和藻细胞解体。藻细胞红外光谱分析表明,经过溶藻物质作用的藻细胞,其蛋白质结构遭到破坏。通过试验结果,推测出菌株S7的溶藻机理:溶藻物质先损伤铜绿微囊藻的细胞壁和粘质胶被,然后通过改变膜的选择透过性进入藻细胞内部,分解叶绿素a,破坏蛋白质,造成藻体正常生理功能的丧失,最终导致藻细胞破裂。  相似文献   

5.
焦酚对共培养铜绿微囊藻和雨生红球藻影响的初步研究   总被引:1,自引:0,他引:1  
以单株藻为对象的纯培养抑藻测试体系被广泛用于化感抑藻活性物质筛选和作用机理研究,但自然水体中藻类常常相伴而生并相互作用,共存藻类对化感物质抑藻效果的影尚不清楚。为探讨藻类共存状态下对化感物质的响应,选择沉水植物穗花狐尾藻(Myriophyllum spicatum)的典型化感抑藻物质焦酚,以有害蓝藻铜绿微囊藻(Microcystis aeruginosa)和经济绿藻雨生红球藻(Haematococcuspluvialis)为受试藻,同时设置混合共培养体系和纯培养体系,比较焦酚对不同培养体系中两株藻的影响。结果显示,纯培养和共培养体系中,焦酚对铜绿微囊藻细胞增长的抑制率分别为96.82%和93.18%,而对雨生红球藻细胞增长的抑制率显著降低,分别为29.39%和45.40%。焦酚处理的纯培养和共培养体系中铜绿微囊藻胞外藻毒素质量浓度分别为3.23、2.00μg·L~(-1),雨生红球藻单个细胞内虾青素质量浓度分别为0.82、1.21 pg·cell-1。与纯培养相比,共培养体系中焦酚对铜绿微囊藻生长的抑制作用减弱,微囊藻毒素释放量显著降低(P0.05),而对雨生红球藻生长的抑制作用增强(P0.05),单个细胞内虾青素积累量最大(P0.05),表明两者共存减弱了焦酚对铜绿微囊藻的抑制效应,却增强了焦酚对雨生红球藻的影响。这些结果初步说明共存藻类会影响化感物质对目标藻株的抑制效应,在后续化感抑藻作用研究中,充分考虑藻类所处生物和非生物环境,将有助于深入揭示水生植物化感抑藻作用生态机制,明确化感作用和化感物质的生态学价值。  相似文献   

6.
微囊藻毒素是由蓝藻产生的环状多肽物质,可引发人类肝中毒等健康问题,因此微囊藻毒素的清除对食品安全和环境保护有着深远的意义.本研究从泡菜、腊肠等传统发酵食品中分离筛选获得33株乳酸菌,通过对其微囊藻毒素清除能力的测定,获得一株具有高效微囊藻毒素清除能力的乳酸菌菌株干酪乳杆菌BBE10-212.实验发现菌体浓度、藻毒素浓度、菌体活性等因素对实验菌株清除藻毒素的效能具有显著影响,此外,外源添加5%的葡萄糖可使藻毒素清除率提高至52%,远高于未添加时的19%.而外源添加替代藻毒素的微生物发酵氮源以及作为部分代谢关键酶辅酶的金属离子则会抑制菌体对藻毒素的清除效率.研究结果为深入分析实验菌株清除微囊藻毒素的作用机制,实现微囊藻毒素的生物干预策略,并基于对菌株的代谢调控促进微囊藻毒素的高效降解提供了数据和资料.  相似文献   

7.
利用阳离子型淀粉复合聚合氯化铝(PAC)制得的混凝剂对铜绿微囊藻进行处理,并进行多因素影响下的比较分析.Zeta电位、扫描电镜等结果表明,相比传统PAC,复合混凝剂所带正电荷量升高,它对藻细胞的电中和作用是对蓝藻重要的去除机理,而PAC水解产物和改性淀粉的吸附架桥和网捕卷扫作用也有重要作用.在所选范围内,复合混凝剂在弱酸性(pH=5.5)和中性条件下(pH=7.5)的去除效果较好,最佳去除率能超过80%.不同pH下复合混凝剂对蓝藻的去除存在最佳投加量,投加量过高时它对蓝藻的去除率发生下降.当达到最佳去除率时,延滞期蓝藻所需复合混凝剂投加量最低,稳定生长期蓝藻需要的投加量最高,蓝藻生长过程中产生的胞外物质是导致该结果的重要原因,具体表现为:蓝藻的胞外多糖(EPS)会增加混凝剂的消耗量,但一定量EPS也有助于混凝剂的作用效果.随着初始藻密度提高(1×105—5×106 cells·mL-1),复合混凝剂对蓝藻的处理效果逐渐发生下降.由于搅拌是为了使混凝剂与藻细胞充分混匀并形成尺寸较大且结构稳定的絮体,因此快搅拌速率不宜过高或...  相似文献   

8.
雨生红球藻不同形态细胞的超微结构研究   总被引:6,自引:0,他引:6  
应用透射电镜观察比较雨生红球藻不同形态细胞的超微结构,结果表明,游动细胞除具有典型的绿藻门团藻目的特征性结构外,细胞壁与原生质体分离形成周质空间,细胞具有发达的可进一步发育的网状叶绿体,不动细胞除了无鞭毛,具厚壁外,它与游动细胞的主要不同是:细胞内的大部分区域被色素沉积物占据,叶绿体等细胞器被包裹,光合片层紧贴,早期的不动细胞还具有较大的线粒体,根据形态及超微结构上的差异,对红球藻游动细胞与不动细胞间的生理差异进行了解释。  相似文献   

9.
水华蓝藻厌氧发酵工艺技术研究   总被引:2,自引:0,他引:2  
以太湖水华蓝藻为底物,用改进的CSTR(continuous stirred tank reactor)工艺,研究了不同有机负荷条件下蓝藻厌氧发酵相关参数与蓝藻藻毒素的去除效果.结果表明:在(35±1) ℃条件下,逐步提高有机负荷,系统运行稳定,有机负荷最高可达3.53 kg·m-3·d-1,此时最大容积产气率达0.89 m3·m-3·d-1,COD去除率在70%左右,甲烷体积分数达60%以上.不同负荷条件下,出料中藻毒素(MC-RR、MC-LR)检测均为阴性,已达无害化处理要求,表明该工艺可以有效处置水华蓝藻,实现能量回收与无害化处理的目标.  相似文献   

10.
为研究纳米氧化锌(ZnO NP)的毒性效应及其在细胞内外分布,以羊角月牙藻(Selenastrum capricornutum)为模型藻类,研究了不同浓度ZnO NP对羊角月牙藻生长、叶绿素含量、可溶性蛋白含量、超氧化物岐化酶(SOD)及过氧化物酶(POD)活性、丙二醛(MDA)含量及细胞内外ZnO NP含量变化。结果表明,ZnO NP对羊角月牙藻的生长抑制与处理浓度呈现正相关。在45 mg·L~(-1)ZnO NP暴露24 h后,其生长抑制率已达到95%。当ZnO NP处理藻细胞72 h后,羊角月牙藻细胞的叶绿素含量与处理浓度之间存在剂量-效应关系。低浓度(0.5 mg·L~(-1))ZnO NP处理后藻细胞可溶性蛋白质含量、SOD和POD活性明显下降,MDA含量升高,其产生的毒性效应高于高浓度组(5 mg·L~(-1)、45 mg·L~(-1))。细胞培养液溶出Zn2+量及藻细胞外吸附的ZnO NP量与ZnO NP处理浓度成正比,但是藻细胞内ZnO NP量与ZnO NP浓度没有相关性,胞内积累量基本维持不变。研究表明,各浓度组对藻细胞毒性的差异,不仅与细胞内Zn2+量有关,还与细胞外粘附的ZnO NP有关。  相似文献   

11.
生物流化床预处理对饮用水致突变活性的影响   总被引:4,自引:0,他引:4  
以C市市区内受污染的N河水为原水,在实验室内建立起生物流化床预处理--传统工艺的组合净水工艺。对原水,传统工艺,生物流化床预处理,组合工艺的出水及其相应的氯化出水Ames试验致突变性研究。以RM和水样比活性表示,非氯化水样的结果表明:传统工艺和生物预处理都会使原水的致突变性有所提高,后者的增幅大于前者;生物预处理能使两类致突变物尤其是碱基置换型致突变物发生有利于被后续传统工艺去除的变化,使组合工艺  相似文献   

12.
As a green oxidant, permanganate has received considerable attention for the removal of micropollutants in drinking water treatment. To provide a better understanding of the oxidation of organic micropollutants with permanganate, the oxidation kinetics of 32 micropollutants were compiled. The pollutants include algal toxins, endocrine disrupting chemicals (EDCs), and pharmaceuticals. The oxidation kinetics of micropollutants by permanganate were found to be first order with respect to both contaminant and permanganate concentrations from which second-order rate constants (k″) were obtained. Permanganate oxidized the heterocyclic aromatics with vinyl moiety (i.e., microcystins, carbamazepine, and dichlorvos) by the addition of double bonds. For the polycyclic aromatic hydrocarbons (PAHs) with alkyl groups, permanganate attacked the benzylic C-H through abstraction of hydrogen. The mechanism for the oxidation of phenolic EDCs by permanganate was a single electron transfer and aromatic ring cleavage. The presence of background matrices could enhance the oxidation of some phenolic EDCs by permanganate, including phenol, chlorinated phenols, bisphenol A, and trichlosan. The toxicity of dichlorvos solution increased after permanganate oxidation, and the estrogenic activity of bisphnol A/estrone increased significantly at the beginning of permanganate oxidation. Therefore, the toxicity of degradation products or intermediates should be determined in the permanganate oxidation processes to better evaluate the applicability of permanganate. The influence of background ions on the permanganate oxidation process is far from clear and should be elucidated in the future studies to better predict the performance of permanganate oxidation of micropollutants. Moreover, methods should be employed to catalyze the permanganate oxidation process to achieve better removal of micropollutants.  相似文献   

13.
The uptake of mercury by water hyacinth (Eichhornia crassipes) was studied in an outdoor experiment for 25 days at different metal concentrations. the removal of mercury from the water and uptake by plants was very effective during the first hours and decreased rapidly thereafter. the uptake of mercury was directly proportional to the initial concentration in the water. the highest concentrations were found in plant roots. According to the results, water hyacinth could be used for treatment of mercurial waste waters.  相似文献   

14.
The uptake of mercury by water hyacinth (Eichhornia crassipes) was studied in an outdoor experiment for 25 days at different metal concentrations. the removal of mercury from the water and uptake by plants was very effective during the first hours and decreased rapidly thereafter. the uptake of mercury was directly proportional to the initial concentration in the water. the highest concentrations were found in plant roots. According to the results, water hyacinth could be used for treatment of mercurial waste waters.  相似文献   

15.
Six wastewater treatment plants (WWTPs) were investigated to evaluate the occurrence and removal of N-nitrosodimethylamine (NDMA), NDMA formation potential (FP) and four specific NDMA precursors, dimethylamine (DMA), trimethylamine (TMA), dimethyl- formamide (DMFA) and dimethylaminobenzene (DMAB). DMA and tertiary amines with DMA functional group commonly existed in municipal wastewater. Chemically enhanced primary process (CEPP) had no effect on removal of either NDMA or NDMA FP. In WWTPs with secondary treatment processes, considerable variability was observed in the removal of NDMA (19%-85%) and NDMA FP (16%-76%), moreover, there was no definite relationship between the removal of NDMA and NDMA FP. DMA was well removed in all the six surveyed WWTPs; its removal efficiency was greater than 97%. For the removal of tertiary amines, biologic treatment processes with nitrification and denitrification had better removal efficiency than conventional activated sludge process. The best removal efficiencies for TMA, DMFA and DMAB were 95%, 68% and 72%, respectively. CEPP could remove 73% of TMA, 23% of DMFA and 36% of DMAB. After UV disinfection, only 17% of NDMA was removed due to low dosage of UV was applied in WWTP. Although chlorination could reduce NDMA precursors, NDMA concentration was actually increased after chlorination.  相似文献   

16.
• Fate of microplastics in integrated membrane system for water reuse was investigated. • Integrated membrane system has high removal efficiency (>98%) for microplastics. • Microplastics (>93%) were mainly removed through membrane bioreactor treatment. • Small scale fiber plastics (<200 μm) could break through reverse osmosis (RO) system. • The flux of microplastics maintained at 2.7 × 1011 MPs/d after the RO treatment. Rare information on the fate of microplastics in the integrated membrane system (IMS) system in full-scale wastewater treatment plant was available. The fate of microplastics in IMS in a coastal reclaimed water plant was investigated. The removal rate of microplastics in the IMS system reached 93.2% after membrane bioreactor (MBR) treatment while that further increased to 98.0% after the reverse osmosis (RO) membrane process. The flux of microplastics in MBR effluent was reduced from 1.5 × 1013 MPs/d to 10.2 × 1011 MPs/d while that of the RO treatment decreased to 2.7 × 1011 MPs/d. Small scale fiber plastics (<200 μm) could break through RO system according to the size distribution analysis. The application of the IMS system in the reclaimed water plant could prevent most of the microplastics from being discharged in the coastal water. These findings suggested that the IMS system was more efficient than conventional activated sludge system (CAS) for the removal of microplastics, while the discharge of small scale fiber plastics through the IMS system should also not be neglected because small scale fiber plastics (<200 μm) could break through IMS system equipped with the RO system.  相似文献   

17.
This research work was performed to evaluate ozonation and granular activated carbon adsorption processes from the view‐point of controlling the formation of disinfection by products (DBPs). Both the humic acid and raw water were first preozonated and then adsorbed on the activated carbon to assess the potency for removal of total organic carbon (TOC) and DBPs. The disinfection by‐product including THMs and HAAs, in principle, can be successfully removed through a use of the ozonation and granular activated carbon (GAC) adsorption processes. However, in practice dealing with the raw water, it is necessary to introduce the pilot‐plant to obtain the design and operation guidelines for the water treatment plant through the ICA (Instrumentation Control and Automation) program in our future research work.  相似文献   

18.
人工湿地脱氮途径及其影响因素分析   总被引:26,自引:0,他引:26  
张政  付融冰  顾国维  杨海真 《生态环境》2006,15(6):1385-1390
简述了人工湿地脱氮模型。各种形态的氮在人工湿地系统中可以通过氨的挥发、植物吸收、介质沉淀吸附以及微生物硝化/反硝化作用等过程被去除。讨论了各脱氮途径对人工湿地脱氮的贡献,在大多数人工湿地的pH条件下,湿地地面氨挥发可以忽略,湿地植物叶片氨挥发量尚不清楚。湿地介质的直接吸附是短期的。植物在湿地脱氮过程中起了重要作用,但一般认为植物直接吸收和存储只占湿地脱氮的一小部分,一般低于30%。微生物的硝化/反硝化作用,是人工湿地脱氮的最主要的形式。讨论了影响人工湿地硝化作用的主要因素:溶解氧,pH和温度。大多数人工湿地的pH适合硝化作用,溶解氧和温度对湿地硝化作用的影响最大。温度不仅影响微生物的硝化作用,而且可以间接地影响植物的生长从而影响人工湿地的脱氮性能。  相似文献   

19.
• 23 available research articles on MPs in drinking water treatment are reviewed. • The effects of treatment conditions and MP properties on MP removal are discussed. • DWTPs with more steps generally are more effective in removing MPs. • Smaller MPs (e.g.,<10 μm) are more challenging in drinking water treatment. Microplastics (MPs) have been widely detected in drinking water sources and tap water, raising the concern of the effectiveness of drinking water treatment plants (DWTPs) in protecting the public from exposure to MPs through drinking water. We collected and analyzed the available research articles up to August 2021 on MPs in drinking water treatment (DWT), including laboratory- and full-scale studies. This article summarizes the major MP compositions (materials, sizes, shapes, and concentrations) in drinking water sources, and critically reviews the removal efficiency and impacts of MPs in various drinking water treatment processes. The discussed drinking water treatment processes include coagulation-flocculation (CF), membrane filtration, sand filtration, and granular activated carbon (GAC) filtration. Current DWT processes that are purposed for particle removal are generally effective in reducing MPs in water. Various influential factors to MP removal are discussed, such as coagulant type and dose, MP material, shape and size, and water quality. It is anticipated that better MP removal can be achieved by optimizing the treatment conditions. Moreover, the article framed the major challenges and future research directions on MPs and nanoplastics (NPs) in DWT.  相似文献   

20.
金属氢氧化物包被砂过滤柱吸附与去除水体中的微生物   总被引:1,自引:0,他引:1  
以氢氧化铁与氢氧化铝原位沉积包被砂作介质的过滤柱 ,用于去除脱氯自来水中人为污染的高浓度脊髓灰质炎病毒PV1、脆弱拟杆菌噬菌体B .fp和大肠杆菌E .coli.结果显示 ,包被修饰砂颗粒表面Zeta电动势由原来的 - 4 2 .8mV上升到 5 4 .7mV ,并因此提高了对微生物的吸附去除能力 .修饰砂过滤柱经 12 .5d连续过滤 30 0L水样后 ,仍可使进水微生物浓度分别高达n(cfu) /mL-1=5 .2× 10 6、2 .4× 10 5、2 .3× 10 5的E .coli、B .fp和PV1去除 92 %、97.2 %和 99.6 % .而未修饰砂柱 ,在相同条件下仅分别去除 5 3%、5 9%和 70 .6 % .修饰砂柱可在较大pH变化下稳定高效地去除微生物且在中性条件下效果最佳 ,这与未修饰砂柱明显不同 .扫描电镜显示 ,两种砂具有明显不同的表面结构 .修饰砂柱流出液中检测不到用于包被的铁、铝金属 ,说明氢氧化铁、氢氧化铝修饰物同砂结合牢固并因此提高了砂过滤柱的使用寿命 .修饰砂过滤介质可为饮用水处理提供更为安全可靠的去除病原微生物方法 .图 4表 4参 19  相似文献   

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