饮用水源突发镉污染的应急处理技术研究

为应对可能出现的突发性镉污染事件,采用连续流试验考察了常规混凝沉淀工艺、KMnO4预氧化/混凝沉淀工艺、粉末炭(PAC)吸附/混凝沉淀工艺、KMnO4和PAC联用/混凝沉淀工艺以及高锰酸盐复合药剂(PPC)预氧化/混凝沉淀工艺对镉的去除效果。结果表明,常规混凝沉淀工艺的除镉效果有限,聚合氯化铝投量为4 mg/L时,对Cd2+的去除率仅为10.5%;KMnO4预氧化/混凝沉淀工艺、PAC吸附/混凝沉淀工艺、KMnO4和PAC联用/混凝沉淀工艺对Cd2+的去除率均有提高,但出水水质仍不能满足国家饮用水水质标准。PPC预氧化/混凝沉淀工艺的除镉效果明显,当PPC投量为3.5 mg/L时,沉后水中剩余Cd2+浓度降低至3.3μg/L,达到了国家饮用水水质标准,去除率为95.2%。因此,PPC预氧化可以作为东江沿岸水厂应对镉污染的一种有效的应急处理措施。     

饮用水中镉污染的应急处理技术中试研究

以模拟遭受突发性镉污染的水体为研究对象,在水厂常规工艺的基础上,考察了化学沉淀技术对镉污染原水的应急处理效果.结果表明,当分别采用三氯化铁和聚合氯化铝为混凝剂时,分别将滤后水pH值控制在8.69和8.58以上,可有效去除超标50倍的镉污染物,且对镉的去除率随着pH值的提高而增大；在最大应急能力方面,将滤后水pH值分别控制在9.17和8.73以上,可分别有效去除超标500和80倍的镉污染物,使镉浓度降至国标限值以下.在混凝前pH值变化不大的情况下,投加聚合氯化铝的滤后水pH值的降低幅度要大于投加三氯化铁的.     

原水突发性铅污染应急处理研究

探讨了采用活性炭吸附、活性炭吸附+聚合氯化铝混凝沉淀联用、聚合氯化铝强化混凝沉淀3种方法对水中铅的去除效果.结果表明,单独采用活性炭吸附对水中铅的去除效果不明显;采用活性炭吸附+聚合氯化铝混凝沉淀联用与单独采用聚合氯化铝混凝沉淀对水中铅的去除效果差别不大;混凝沉淀可有效去除单纯水源水、水源水与运河水等体积配水条件下的铅,最高去除率达到90％,最大去除能力为5倍标准限值.     

复合磁种混凝与磁混凝处理黑臭水体效能比较

在制备和表征纳米Fe₃O₄-沸石复合磁种的基础上,系统比较了混凝、磁混凝和复合磁种混凝三种工艺对黑臭水体的处理效能。结果表明,复合磁种中铁元素含量约为20.0%,沸石的骨架结构和成分未被改变。聚合氯化铝(PAC)和磁种投加量分别为60 mg/L和1～2 g/L时,磁混凝和复合磁种混凝可获得较优的黑臭水体处理效果。磁混凝可强化混凝效果,提高对浊度、TP和COD的去除率,但无法有效去除氨氮;复合磁种混凝可有效去除水中氨氮,全面提升出水水质。黑臭水体中的污染物主要以溶解态形式存在,混凝和磁混凝不能有效去除溶解性污染物,因此对氨氮和COD的去除效果较差;但可通过化学除磷获得较高的TP去除率。复合磁种混凝可利用沸石的离子交换和吸附作用强化对溶解性污染物的去除,获得较好的氨氮和COD去除效果;同时,还可利用负载的纳米Fe₃O₄实现极限除磷。     

化学沉淀法强化常规工艺去除水中镍的应急处理

以模拟遭受突发性镍污染的水体为研究对象,考察了化学沉淀法强化常规水处理工艺对镍污染原水的应急处理效果.结果表明,该方法能有效去除饮用水水源中的镍,可作为突发性饮用水水源镍污染的应急处理措施;pH对除镍效果有较大影响,故在水厂现有常规工艺基础上,通过调整混凝前原水的pH值,保证滤后水的pH值在9.0以上,即可使出厂水水质满足《生活饮用水卫生标准》(GB 5749-2006)要求;聚合氯化铝在高pH值条件下存在铝超标风险,故化学沉淀法除镍时宜选用三氯化铁作为混凝剂.     

混凝沉淀/膜处理组合工艺处理蓄电池生产废水

采用混凝沉淀/膜处理组合工艺处理蓄电池生产废水,处理量为5.0m3/h,进水pH值为2～4,总铅为10mg/L,总镉为5mg/L。运行结果表明,混凝沉淀工艺可有效去除废水中的重金属离子,再结合膜处理工艺可确保处理出水总铅浓度为0.1～0.3mg/L,总镉浓度为0.01～0.02mg/L,出水进入清水池贮存并回用于生产(回用率70%),排放水质均达到《污水综合排放标准》(GB8978—1996)的一级标准。半年多的实际运行结果表明,采用该组合工艺处理蓄电池生产废水,效果稳定、耐负荷冲击性强,具有广阔的工业应用前景。     

饮用水源突发性锑+铊复合型污染应急处理研究

为应对可能出现的突发性铊+锑复合型污染事件,模拟自来水厂现有工艺对含有锑(Sb)和铊(Tl)的原水进行处理,分别考察了常规混凝沉淀工艺、K2Fe O4预氧化/混凝沉淀工艺以及分段处理工艺对Tl和Sb的去除效果。结果表明,常规工艺对Sb和Tl的去除效果均有限;K2Fe O4预氧化/混凝沉淀工艺对Tl的去除效果有明显提高,但对Sb的去除率反而降低;分段处理工艺对Sb和Tl都有明显的去除效果,当第1段聚合氯化铁(PFC)的投加量为10.0 mg/L,第2段K2Fe O4、聚合氯化铝铁(PAFC)的投加量分别为1.0、1.5 mg/L时,滤后水中剩余Sb、Tl的浓度分别为2.26、0.012μg/L,去除率分别达到了83.67%和96.32%。因此,分段处理可作为水厂应对突发性铊+锑复合型污染的有效应急处理措施。     

混凝沉淀工艺深度处理污水厂二级出水的混凝剂优化

通过烧杯试验，确定了采用混凝、沉淀工艺深度处理城市污水处理厂二级出水时，最佳的混凝剂组合及投量。结果表明，铝盐混凝剂与PAM组合使用时比铁盐混凝剂与PAM组合使用时的处理效果更好，当PAC＋PAM的组合投量为20mg／L＋5mg／L或30mg／L＋1mg／L、硫酸铝＋PAM的组合投量为30mg／L＋5mg／L时，混凝、沉淀出水浊度为2．5～3．5NTU，COD为25-40mg／L，TP为0．06-0．12mg／L。由于混凝后水中所形成的絮体较小，难于沉淀，因此混凝沉淀工艺对SS的去除效果较差，实际工程中可考虑增设过滤单元。     

水源水中乐果污染物应急处理工艺的试验研究

以乐果为目标化合物,探讨了活性炭吸附、活性炭吸附-混凝沉淀工艺以及石灰碱解-活性炭吸附-混凝沉淀三种工艺对乐果的去除效果.结果表明,乐果的去除效果随着活性炭投加量与吸附时间的增加而增加,采用活性炭吸附-常规混凝沉淀工艺对乐果的去除效果要略好于单独采用活性炭吸附,但这两种工艺都不能有效去除水中的乐果.采用石灰碱解-活性炭吸附-混凝沉淀工艺时,乐果的去除率随着石灰碱解的pH值升高而增加.当原水乐果含量为0.182 mg/L,用石灰调节原水pH值为9,投加30 mg/L活性炭吸附20 min后,去除率达89.9%,沉淀出水乐果浓度为0.018 4 mg/L,满足标准要求.     

高锰酸钾-粉末活性炭联用去除原水中的嗅味

针对常规处理工艺难以解决东江原水发臭的问题,考察了高锰酸钾-粉末活性炭联用技术对水中嗅味的去除效果。结果表明,高锰酸钾一粉末活性炭联用对水中嗅味具有较好的去除效果,当氧化吸附时间为30min,高锰酸钾投加量为1．5mg/L,粉末活性炭投加量为40mg／L时,经混凝沉淀后水中的嗅味可由5级降至0级。此外,高锰酸钾和粉末活性炭联用对水中的有机物、浊度及锰也有明显的去除效果。     

Impact of recycling filter backwash water on organic removal in coagulation-sedimentation processes

The overall purpose of this research was to examine the impacts of filter backwash water (FBWW) and membrane backwash water (MBWW) recycles on water quality in coagulation-sedimentation processes. Specifically, the impact of recycling 5 or 10% by volume of FBWW and MBWW with surface water on the removal of natural organic matter (NOM) was evaluated at bench-scale using a standard jar-test apparatus and measurement of specific water quality parameters including total organic carbon (TOC), dissolved organic carbon (DOC), UV254, turbidity, total aluminum and zeta potential. The results of jar test conducted on a source water with a specific UV absorbance (SUVA) value within the range of 2-4 mg/L m showed a significantly higher removal of DOC from the raw water that was blended with 5 and 10% by volume of FBWW as compared to control trials where backwash water was not added. Increasing rates of MBWW that did not contain destabilized hydroxide precipitates did not significantly change DOC concentrations in the settled water samples as compared to the control trials. For source waters that are characterized as having low turbidity with medium SUVA values, these results could hold particular significance for plants that have reached treatment ceilings in terms of dissolved NOM removal using conventional coagulation designs.     

Estuarine capacity in removal of trace metals from contaminated river water, Southern Caspian Sea

In the present investigation, the flocculation of dissolved Cd, Cu, Ni, Pb, Mn and Zn with initial concentrations of 1, 2.5 and 5 mg/L in Tadjan River water during mixing with the Caspian Sea water has been studied in order to determine estuarine capacity to remove dissolved metals in the accidental contamination of the river. The flocculation process was investigated on a series of mixtures with salinities ranging from 0.1 to 11 p.p.t. The flocculation rates were indicative of the nonconservative behaviour of Cd, Cu, Ni, Pb, Mn and Zn during estuarine mixing. The order of the final flocculation rate of dissolved metals at 1, 2.5 and 5 mg/L of initial metal concentrations in the river water is as follows:Cu (99%)>Cd (95%)>Zn (88%)>Mn (85%)>Pb (83%)>Ni (73%), Cu(95.6%)>Pb(92.4%)>Cd (90%)>Zn(88.4%)>Mn (81.6%)>Ni(78.8%) and Cd (100%)>Cu(88%)>Ni (85.2%)>Pb (84%)>Zn (83.2%)>Mn (81.2%), respectively. The results also revealed that removal of dissolved metals is not influenced by pH changes and precipitation processes. The flocculation rates revealed that the overall dissolved metal pollution loads may be reduced to about 70% up to about more than 90% during estuarine mixing of Tadjan River with the Caspian Sea water.     

Dissolved organic matter (DOM) in recycled leachate of bioreactor landfill

Landfill leachate needs sufficient treatment before safe disposal. Bioreactor landfill technology could effectively degrade the organic matters in recirculated leachate, hence leaving a leachate stream of low biodegradability. This study characterized the dissolved organic matter (DOM) in the leachate from simulated bioreactor landfill columns with or without presence of trace oxygen. The removal efficiencies of this DOM using coagulation-sedimentation or electrolysis processes were demonstrated. Recirculated leachates were sampled from the simulated landfill columns applying conventional mode, intermittent-aeration mode, and natural aeration mode, whose DOM was fractionated into humic acids (HA), fulvic acids (FA) and hydrophilic fractions (HyI) by the XAD-8 resin combined with the cation exchange resin method. The recirculated leachate had low BOD/COD ratio, high humic substances contents, and high aromatic content. Their HA fraction comprised mainly large molecules (>10 k Da), while the FA and HyI were composed of smaller molecules (<50 k and <4 k Da, respectively). With the presence of oxygen, the TOC contents and the contents of HA, FA and HyI in leachate reduced, with FA and HyI fractions of molecular weight (MW) lower than 4 k Da more readily degraded. The organic matters left in leachates from intermittent-aeration mode and natural aeration mode were of low biodegradability. It was tested in the following sections the effects of coagulation-sedimentation process and of electrolysis process on the removal of residual DOM in recirculated leachate. Coagulation-sedimentation tests revealed that poly ferric sulphate (PFS) could remove more COD (58.1%) from leachate than polyaluminum chloride (PACl) (22.9%), particularly on the HA fraction with MW>10 k Da. Coagulation-sedimentation could not remove most of HyI in leachate. Furthermore, the corresponding BOD/COD ratio was not improved through coagulation. Electrolysis test could also effectively removed HA of MW>10 k Da. However, the biodegradability of treated effluent considerably was improved. The electrolysis could decompose high MW substances and increase biodegradability of recirculated leachate from bioreactor landfill.     

Removal of heavy metals from storm and surface water by slow sand filtration: the importance of speciation

The removal of heavy metals from storm and surface waters by slow sand filtration is described. The importance of speciation as a technique for exploring and improving the mechanisms of removal is identified. Laboratory-scale slow sand filters operating at conventional flow rate and depth were shown to be able to reduce concentrations of selected heavy metals (Cu, Cr, Pb and Cd) found in road runoff, surface water and sewage effluents to drinking water standard. Nitrogen, volatile solids and modified Stover speciation were used to differentiate between the potential mechanisms of removal, i.e. active biomass, organic adsorption and simple adsorption or precipitation on the surface of the sand. The data presented show that adsorption via organic ligands was the predominant mechanism for metal removal at the surface of the filter but chemical adsorption was the more important deeper in the filter. In the lower layers the adsorbed metals were more easily exchanged than the organically bound metals. The precise chemical ligands were not identified and varied from metal to metal. The most important operational factors affecting performance were therefore the concentration of organic matter, filter depth and the flow velocity.     

珠江水中有机物分子量分布及其去除研究

采用超滤膜分级方法考察了常规混凝、高锰酸钾和粉末活性炭预处理等工艺对珠江水中各级分子量有机物的去除效果。结果表明,珠江水中有机物以分子量小于1kDa的小分子有机物为主,各级分子量有机物TOC和UV254具有良好的相关性。常规混凝工艺主要去除大分子有机物,且去除率随分子量的减小而降低。高锰酸钾预处理能够全面提高各级分子量有机物的去除效果;粉末活性炭主要吸附中小分子有机物,对各级分子量有机物的去除效果与常规混凝成互补。     

南方某水厂臭氧/活性炭深度处理工艺运行效果

以南方地区微污染水源水为对象,研究臭氧/活性炭深度处理工艺对有机物综合指标UV(254)、COD(Mn)、TOC的去除效果以及对消毒副产物的控制效果,并结合三维荧光光谱技术分析溶解性有机物的荧光特性。结果表明,与常规处理工艺相比,增加臭氧/活性炭深度处理工艺后,对UV(254)、COD(Mn)、TOC、三卤甲烷前体物的去除率分别提高了47.05%、20.24%、31.11%、37.70%。三维荧光光谱分析结果表明,该地区微污染水源水主要由芳香性蛋白质类物质、溶解性微生物代谢产物类物质和富里酸类物质组成,臭氧/活性炭深度处理工艺对荧光溶解性有机物的去除效果明显。     

The effectiveness of conventional trickling filter treatment plants at reducing concentrations of copper in wastewaters

Eight different sewage treatment works were sampled in the North West of England. The effectiveness of the conventional treatment processes (primary sedimentation and biological trickling filters) as well as various tertiary treatment units in terms of both total and dissolved copper removal was evaluated. The removal of total copper across primary sedimentation averaged 53% and were relatively consistent at all sites, however, at three sites the removal of dissolved copper also occurred at this stage of treatment. Removal of total copper by the biological trickling filters averaged 49%, however, substantial dissolution of copper occurred at two sites, which highlighted the unpredictability of this treatment process in the removal of dissolved copper. Copper removal during tertiary treatment varied considerably even for the same treatment processes installed at different sites, primarily due to the variability of insoluble copper removal, with little effect on copper in the dissolved form being observed. The proportion of dissolved copper increased significantly during treatment, from an average of 22% in crude sewages to 55% in the final effluents. There may be the potential to optimise existing, conventional treatment processes (primary or biological treatment) to enhance dissolved copper removal, possibly reducing the requirement for installing any tertiary processes specifically for the removal of copper.     

颗粒活性炭吸附去除黄浦江原水中有机物的研究

采用超滤膜法分析了黄浦江原水和水厂常规工艺处理出水中有机物的分子质量（MW）分布以及颗粒活性炭（GAC）在不同吸附阶段吸附去除不同分子质量有机物的性能.试验结果表明,黄浦江原水及常规工艺出水中的溶解性有机物（DOC）以小分子为主,并主要集中在MW为10～30 ku和MW＜1 ku的区间;活性炭吸附出水中的溶解性有机物仍然主要集中在小分子区间;吸附初期的活性炭对有机物的去除能力较强,其中对CODMn的去除率＞83%,对UV254的去除率＞90%;随着通水倍数的增大则活性炭的吸附能力逐渐下降,当通水倍数达到6 590.9时,对CODMn和UV254的去除率都只有25%左右;活性炭吸附的各个阶段对小分子有机物的去除率均较高,而对大分子有机物的去除率则较低,从吸附初期到吸附后期,对小分子有机物的去除率高出对大分子有机物的去除率,其百分比从10%增大到30%.     

化学生物絮凝工艺对溶解性有机物的去除特性

研究了化学生物絮凝工艺对溶解性有机物的去除效果及其分子质量分布的变化特征，并分别与化学强化一级工艺、初沉池和二级生物处理工艺的出水进行对比。试验结果显示：化学生物絮凝工艺对分子质量〉2ku的有机物去除效果明显；对溶解性有机物和UV260的去除率分别为45．9％和38．7％，与城市污水二级生物处理工艺相比，其去除溶解性有机物的能力较弱；对溶解性有机物的去除是通过化学和生物作用共同实现的，其中生物作用主要表现为生物吸附作用。     

Impact of polyhexamethylene guanidine on filtering of Pb(II) and Cd(II) hydroxides from aqueous solutions

The paper presents results of investigations aimed at optimizing the process of Pb(II) and Cd(II) removal using polyhexamethylene guanidine (PHMG) from aqueous solutions. The formation of compounds of chemisorption-type ions of the above metals with PHMG was established by using the methods of polarography, infrared spectroscopy, and pH-metry. The investigations revealed a positive impact of PHMG on the sedimentation and filtering of the precipitation of Pb(II) and Cd(II) hydroxides.