不同预处理方式与微滤联用处理城市污水对比实验研究

采用微滤法处理模拟二沉池出水,以期达到城市污水回用的目的.进水采用人工配水,主要考察微滤膜对模拟二沉池出水中CODMn,氨氮(NH3-N)及UV254的去除效果,以及预处理方式对微滤膜处理工艺的影响.实验主要采用了两种预处理方式,即颗粒活性炭(GAC)吸附及聚合氯化铝(PAC)混凝.实验结果表明,单独采用微滤膜效果不明显,高锰酸钾指数的去除率仅为32.5%,氨氯去除率约为5%,且膜污染严重,通量下降很快.活性炭-微滤组合工艺对污水的CODMn去除效果较好,去除率达到88%;而混凝-徽滤工艺对UV254的去除效果较好,去除率达到87%;混凝-微滤及活性炭-微滤工艺对氨氮的去除率均不高.组合工艺比起单独使用微滤膜流量下降缓慢,混凝-徽滤工艺在4.5h内,流量没有下降,污染情况明显改善.     

强化混凝技术处理东太湖原水研究

在常规混凝工艺确定的最佳处理条件下,考察了单独高锰酸钾(KMnO4)和次氯酸钠(NaClO)预氧化、单独投加粉末活性炭(PAC)以及KMnO4和PAC联用对混凝处理东太湖原水的强化效果。结果表明,聚氯化铝和硫酸铝的最佳投加量分别为20mg/L和30mg/L,聚氯化铝的混凝效果明显优于硫酸铝;投加KMnO4对浊度、CODMn和UV254的去除均有一定程度提高,但不利于原水氨氮的去除;投加PAC有显著的强化混凝作用,各指标去除率均有所提高;KMnO4和PAC联用能进一步提高水中UV254的去除率;预氧化大大提高了混凝对氨氮的去除效果,投加1mg/L NaClO对氨氮去除率可达100%。     

全膜深度处理工艺处理太湖水的中试研究

采用超滤-纳滤(UF-NF)全膜工艺处理东太湖水,通过中试考察全膜工艺对水中各种污染物的处理效能。试验结果表明,超滤预处理能充分保证纳滤的稳定运行,试验工艺处理浊度、COD_(Mn)、TOC、UV_(254)、氨氮、藻密度和叶绿素a的去除率分别为99.93%、89.33%、62.33%、93.72%、82.1%、99.67%和98.32%。工艺对水中的TDS和电导率的去除率为43%。三维荧光和有机物特性分析表明,原水中有机物构成以芳香蛋白类物质、溶解性微生物代谢产物和小分子有机物为主,全膜工艺去除效果优异。     

微污染水库水超滤膜处理工艺的试验研究

利用PVC合金超滤膜中试装置与不同预处理组合成"混凝-超滤"、"混凝-沉淀-超滤"和"混凝-气浮-超滤"3种工艺处理微污染水库水,研究其净水效果及跨膜压差变化规律。结果表明:3种组合工艺的浊度去除率均在99%以上;镜检出水细菌、藻类含量基本接近零;对CODMn、UV254的去除效果顺序为:"混凝-气浮-超滤""混凝-沉淀-超滤""混凝-超滤";红外光谱分析结果显示,亲水性有机物是引起膜污染的主要物质;低温低浊期,跨膜压差随着产水时间变化趋势线的斜率为0.016 4、跨膜压差平均值为23.57 k Pa;高温高藻期斜率为0.043 2、跨膜压差平均值为21.28k Pa。     

水处理工艺过程中有机物分子量分布规律

针对太湖流域某湖泊水源有机物分子量分布的特性,考察饮用水处理各工艺单元对有机物的去除效应。结果表明:原水以小分子量有机物为主,小于1k Dalton的有机物占36.1%;常规工艺对大分子量有机物去除率高,尤其对分子量在10k Dalton以上的有机物去除率达32.7%以上,但对小分子量有机物去除率低,其中分子量小于1k Dalton的有机物反而增加了12.6%左右。超滤深度处理工艺中PES膜工艺对小分子量有机物,特别是分子量小于10kDalton的有机物去除率达76.4%,出水UV254值及SUVA值比砂滤出水分别下降了22.0%和11.2%;PVDF膜工艺对各分子量有机物均有较好的去除,但对大分子有机物去除效果优于小分子有机物,其出水UV254值及SUVA值比砂滤出水分别下降了28.8%和6.3%。     

臭氧预氧化技术处理地表水的试验研究

以低温低浊度地表水为研究对象,研究了臭氧预氧化对浊度、色度、UV254、TOC、CODMn、藻类的去除效果及对后续气浮、过滤等常规工艺处理效果的影响。对于低温低浊度地表水预臭氧化具有明显助凝作用,可以提高混凝沉淀效果,同时可以降低原水色度。预臭氧化去除有机物效果明显。     

活性炭过滤与超滤工艺在中水回用中的应用比较

分别用炭滤和超滤两种工艺处理生活污水，结果发现炭滤和超滤对 CODCr和 UV254去除效果相当，去除率在45％～75％之间，而超滤对浊度和细菌及大肠杆菌的去除率远高于炭滤。     

五种预处理方式对超滤膜处理松花江水的效能比较

采用中试对比考察了不同预处理方式(包括混凝、砂滤、混凝-砂滤、高锰酸钾-混凝-砂滤、粉末活性炭)对超滤膜渗透性能及其对去除松花江水中污染物的影响.结果表明:以松花江水为原水,在超滤膜之前进行预处理是必要的.其中单独混凝会使膜通量降低,投加高锰酸钾使膜通量显著增加,并可延缓膜通量的下降速度,投加粉末活性炭对提高膜通量作用不大;不同预处理均能保证超滤膜出水浊度低于O.3 NTU,大于2 μm颗粒数少于10个/mL;此外,不同的预处理均能提高超滤膜对水中有机物的去除效果,高锰酸钾-混凝-砂滤-超滤对DOC、UV254的去除率分别为37.5%、28%.     

NO2-N含量对预臭氧化工艺效果影响研究

探讨了深圳某给水厂原水中NO2--N含量对预臭氧化工艺效果的影响.室内静态试验结果表明,深圳原水的O3消耗量与NO2--N完全去除的比例为51(O3消耗量/NO2--N的理论值约为3.4);当原水NO2--N＜0.1 mg/L时,NO2--N对预臭氧工艺无影响,而当NO2--N＞0.18 mg/L后,预臭氧化工艺去除有机物效果(以UV254表征)明显降低;水厂生产结果表明,NO2--N含量对预臭氧化工艺中的臭氧投加量及处理效果具有显著影响,原水中较高的NO2-N还会对后续混凝沉淀和砂滤工序造成不良影响,原水经生物预处理和封闭管道改造后,NO2--N由0.12～1.85 mg/L降低到0.02～0.14 mg/L,CODMn去除率明显升高.     

美国ICR数据库有机物去除分析及对我国的借鉴作用

我国《生活饮用水卫生标准》(GB 5749-2006)对有机物指标的要求,给我国给水处理的运行带来了新的挑战。依照美国第一阶段消毒剂与消毒副产物标准中对有机物指标(TOC)的去除率要求,用美国ICR(Information Collection Rule)数据库分析了常规工艺及增加生物活性炭(BAC)的深度处理工艺对水中有机物的去除。结果表明,常规工艺对有机物的去除效果随原水的TOC增大而变好,随碱度增大而变差;对于水中有机物的去除,常规工艺的去除率中位数为32%,BAC的深度处理工艺中位数为40%。混凝和BAC工艺弥补了各自的不足,尤其是当原水碱度较高TOC较低,在混凝工艺后增加BAC工艺可以更好地去除水中的有机物。     

组合工艺控制有机物及消毒副产物前体物的特性研究

通过XAD-8树脂将水中有机物分成疏水性、亲水性两部分,对传统常规处理工艺(混凝气浮、过滤)和深度处理工艺(臭氧氧化、生物活性炭)出水的DOC,UV254THMFP,HAAFP指标以及疏水、亲水有机物去除率进行了检测分析。结果表明,生物活性炭(BAC)单元工艺能同时去除疏水性和亲水性两种有机物,且两者去除率均为最高。其次去除效果较好的是传统的常规工艺。臭氧工艺具有将天然的疏水性有机物氧化成可生化降解的亲水性小分子有机物的特点,在预臭氧+常规以及O3-BAC组合工艺中,起到了强化去除有机物和消毒副产物前体物的效果。     

Activation of solgel titanium nanofilm by UV illumination for NOM removal.

The control of natural organic matter (NOM) in drinking water treatment plants is required in order to control (i) the formation of potentially harmful disinfection byproducts (DBPs), (ii) the regrowth of bacteria and (iii) pipe corrosion in the distribution system. Photocatalysis is a promising advanced oxidation technology due to its ability to mineralise chlorinated byproduct precursors such as humic acids (HAs) to carbon dioxide and water. In this study, the efficiency of HAs and NOM removal in terms of UV absorbance at 254 nm (UV254) was tested by means of a new photocatalytic reactor made of stacked polymethylmethacrylate (PMMA) rings coated by TiO2 nanofilm. Three different sets of rings were coated with TiO2 gel one, two and three times respectively to optimise the coating thickness according to UV254 removal efficiency. The titania sol was immobilised on the substrate by a low temperature procedure and after 8 months the reactors were reactivated by means of UV radiation before the experiments. The photocatalytic removal efficiency of humic acid in terms of UV254 was significantly higher after 1 hour for the reactor employed with high thickness TiO2 nanofilm (around 20%) compared to middle and low thickness reactors (6 and 1.4%, respectively). However, during the same reaction time only 10% of UV254 was removed with high thickness TiO2 nanofilm using raw surface water, probably owing to ionic species naturally occurring in the raw water sample. Finally, the activation of the TiO2 nanofilm may be effectively accomplished by means of UV radiation where calcination cannot be applied (e.g. thermally sensitive substrates).     

Comparison of AOPs for the removal of natural organic matter: performance and economic assessment.

Control of disinfection by-products during water treatment is primarily achieved by reducing the levels of organic precursor species prior to chlorination. Many waters contain natural organic matter at levels up to 15 mg L(-1); therefore it is necessary to have a range of control methods to support conventional coagulation. Advanced oxidation processes are such processes and in this paper the Fenton and photo-Fenton processes along with photocatalysis are assessed for their NOM removal potential. The performance of each process is shown to be dependent on pH and chemical dose as well as the initial NOM concentration. Under optimum conditions the processes achieved greater than 90% removal of DOC and UV254 absorbance. This removal led to the THMFP of the source water being reduced from 140 to below 10 microg L(-1), well below UK and US standards. An economic assessment of the processes revealed that currently such processes are not economic. With advances in technology and tightening of water quality standards these processes should become economically feasible options.     

AOPs with ozone and UV radiation in drinking water: contaminants removal and effects on disinfection byproducts formation.

In this study, the advanced oxidation with ozone and UV radiation (with two low pressure UV lamps, at 254 and 185 nm wavelength) were experimented on a surface water in order to study the removal of two odorous compounds (geosmin and 2-methylisoborneol) and a pesticide (metolachlor), the influence on organic compounds (UV absorbance and THM precursors) and bromate formation. Different batch tests were performed with ozone concentration up to 10 mg/L, UV dose up to 14,000 J/m2 and a maximum contact time of 10 minutes. The main results show that metolachlor can be efficiently removed with ozone alone while for geosmin and MIB a complete removal can be obtained with the advanced oxidation of ozone (with concentration of 1.5-3 mg/L and contact time of 2-3 minutes) with UV radiation (with doses of 5,000-6,000 J/m2). As concerns the influence on the organic precursors, all the experimented processes show a medium removal of about 20-40% for UV absorbance and 15-30% for THMFP (trihalomethanes formation potential). As concerns bromate formation, the advanced oxidation of ozone/UV 254 nm shows a bromate formation that is about 40% lower with respect to conventional oxidation with ozone.     

UV/H2O2联用工艺去除水中微量有机污染物的中试研究

为了考察UV/H2O2工艺对微量有机物的去除效果,在砂滤池出水后接UV/H2O2高级氧化中试设备,并投加了特征污染物(阿特拉津、臭味物质2-MIB与Geosmine)。结果表明,UV/H2O2工艺对Geosmine去除效果最好,去除率能达到90%以上,对MIB和阿特拉津的去除效果比较接近,去除率均在50%以上,对UV254的去除率为20%～38%。在UV/H2O2工艺中无溴酸盐生成。     

地表水中UV254与COD之间的关系分析

通过对南京地区3种不同类型地表水的紫外吸光度UV254及其他一些水质指标的检测分析,采用线性拟合的方法分析其与CODMn和COD的相关性。结果表明:在特定的、水质较稳定的河流中,UV254与有机指标有特定的相关曲线,水质差的河流中两者相关性高于水质较好的河流;在分布较广、水体特征不一的湖泊水库中其相关性较差。     

Implementing Treatment Sequences to Promote Reduction of DBPs in Small Drinking Water Systems

The performance of three drinking water treatment sequences found in small community systems in reducing disinfection by-product precursor concentrations and the corresponding disinfection by-product formation potential was evaluated. Raw water quality and its potential for effective removal were characterized by the specific ultraviolet absorbance (SUVA) components of absorbance of ultraviolet light at 254 nm wavelength (UV254) and dissolved organic carbon (DOC). The results demonstrate that, for the source water qualities tested (hydrophobic SUVA with moderate DOC content, 2.0 to 4.8 L/(mg.m) and 4.1 to 6.3 mg DOC/L), there was a tendency to produce a higher percentage of total trihalomethane (TTHM) over the five regulated species of haloacetic acid (HAA5). The treatment sequence and chemical selection play a critical role in the ability of a small community system operator to achieve compliance with the concentration of regulated disinfection by-products. For the waters tested ferric chloride coagulants perform better at reducing the higher molecular weight, hydrophobic organic precursors. Powdered activated carbon does not perform as well with these source waters unless its application is followed by a clarification process that effectively forms a sludge blanket. This research provides additional criteria for linking source water quality with treatment sequence for sustainable management of disinfection by-product (DBP) compliance.     

复配缓释凝胶吸附处理剂的制备及其除磷释氧性能

研制了海藻酸钠包埋壳聚糖凝胶小球和海藻酸钠/聚乙二醇4000复合包埋纳米过氧化钙缓释凝胶小球复配处理剂,考察其对水体中磷和有机物的去除效果及机理,采用X射线衍射、扫描电镜、元素能谱仪技术表征材料物化及形貌特征。该处理剂能够高效去除水中单一的磷和有机污染物,且对磷和甲基橙复合污染也具有较高的去除率;在实际河道水体中,该处理剂对高浓度的磷也具有较强的吸附能力,其缓慢释氧作用可保持水体溶解氧质量浓度在4.5 mg/L以上,为泥水界面处的好氧微生物提供了良好的好氧条件,可提高水体自净能力。     

长江常熟段水溶解性有机物分子质量分布特性

采用超滤膜法对水溶解性有机物进行物理分级,研究长江常熟段水源水中不同分子质量区间DOC和UV254分布的变化特征及其原因。结果表明,长江常熟段水源水总体水质较好,高锰酸盐指数、氨氮、总磷等指标均未超过地表Ⅲ类水体水质标准,符合饮用水源地卫生要求。2008年11月至2009年9月期间,水源水中分子质量小于1kDa的DOC所占比例平均为64.3%,分子质量小于1kDa的UV254所占比例平均为45.2%,表明长江水源水中水溶解性有机物主要以小分子质量的有机物为主,汛期水源水中分子质量在3～10 kDa区间的DOC和UV254比例较枯水期有显著提高。     

一体化超滤-膜混凝吸附生物反应器饮用水除污染效能

为了提高超滤-膜生物反应器(UF-MBR)的饮用水除污染效果,在其反应器中直接投加粉末活性炭进行吸附和聚氯化铝进行混凝,构建一体化超滤-膜混凝吸附生物反应器(UF-MCABR)。试验结果表明,在投药量为粉末活性炭8mg/L、聚氯化铝10mg/L时,UF-MCABR对TOC和CODMn的去除率比UF-MBR分别提高了37.1个百分点和29.8个百分点;对DOC和UV254的去除率分别提高了40.6个百分点和61.4个百分点,并取得了几乎100%的硝化效率和PO34-—P去除效率。UF-MCABR的膜污染速率较之UF-MBR显著降低。