膜过滤复合过程污染阻力分析及清洗

对生物反应器---膜过滤复合过程处理模拟腈纶废水进行了研究,探索了膜微滤过程中的污染机 理。通过对微滤膜处理模拟腈纶废水过程中各部分阻力进行分析,结果表明在较低操作压力条件下,膜的污染主要 是浓差极化和滤饼层污染;在较高操作压力条件下,则主要是来自滤饼层污染;来自膜孔阻力和膜自身的阻力较小 是膜污染的次要因素。提出了膜清洗的具体方案,用质量分数1%的双氧水溶液清洗30min或0.1mol/L的氢氧化 钠溶液清洗60min,均可以使膜通量恢复到较好的水平。     

移动载体膜生物反应器膜污染控制研究

研究了移动载体复合式膜生物反应器(MCMBR)的膜污染特性和机理.通过对比MCMBR和传统膜生物反应器(CMBR)的跨膜压力变化,分析了MCMBR反应器的膜过滤特性.应用RIS(resistance-in-series)模型分析比较了MCMBR和CMBR的膜阻力构成,通过共聚焦显微镜拍照对滤饼层微观结构进行了研究.结果表明:跨膜压力达到30 kPa时,MCMBR的跨膜压力平均上升速率为CMBR的37.5%;MCMBR反应器膜污染状况的改善主要表现在移动载体对滤饼层阻力的减缓作用;相同操作时间下,MCMBR膜滤饼比阻仅为CMBR的25%,MCMBR反应器过滤性能增强的根本原因是移动载体的存在有利于减小滤饼层质量和增大滤饼层孔隙率.     

颗粒体系错流微滤过程临界点研究——临界点的数值识别

以传统的滤饼层阻力和与诱导扩散相结合的浓差极化模型为基础,建立了刚性颗粒悬浮液体系错流微滤过程中模拟临界点的数学模型。模型的模拟和预测结果与实验值吻合很好。用该模型不仅能计算错流微滤过程中临界点的临界压力、临界错流速度和临界滤饼层厚度,还可以对临界点的性质与微滤中各项参数的关系进行预测。模型的提出为更好地理解颗粒体系错流微滤中的膜污染机理,并在实际应用中通过控制过滤操作参数来减小或消除此类膜面污染提供了理论依据。     

陶瓷膜分离对氨基苯酚料液中催化剂微粒研究

对陶瓷膜微滤分离净化含骨架镍催化剂的对氨基苯酚料液的工艺进行研究,通过小试实验确定采用 孔径为0.2μm 的陶瓷膜过滤对氨基苯酚料液,对工业上用过的污染膜和滤饼层的组分分析表明,污染物主要是骨架 镍催化剂。提出了工业应用中膜清洗的具体方案,在100 ℃下用酒精-水溶液清洗膜装置10min,体积分数为1% 的NaOH 溶液清洗20min,体积分数为3%的硝酸溶液清洗1h,工业软水清洗1h。经过工厂长期运行,膜的平均 渗透通量是400L/(m2·h),用原子吸收光谱仪在全部过滤运行的渗透液中没有检出镍,可见在工业环境中用陶瓷 膜微滤对氨基苯酚料液是一种可靠和有效的净化技术。     

陶瓷微滤膜处理大理石加工废水的研究

采用孔径为0 .8 μm 的陶瓷膜处理大理石生产过程中产生的废水, 研究了操作压差和膜面流速等对膜性能的影响。结果表明, 合适的操作条件是操作压差0.07 M Pa , 膜面流速1 .0 m/ s, 滤出液中固体颗粒的截留率在99 .2 %～ 99 .8 %, 膜微滤过程对废水的pH 值和COD 值的影响不大。运行中膜通量稳定平均值为400 L/(m2 · h), 料液的固体质量浓度大于55 g/ L 时, 膜通量明显下降。对污染膜用清水清洗20 min 和体积分数为1 %的H NO3 溶液清洗30 min , 膜通量可以得到完全恢复。渗透液返回生产工序循环使用, 截留液进入沉降池。     

微絮凝-超滤联用工艺处理低温水膜污染的机理

通过微絮凝-超滤联用工艺处理不同温度水样,研究了微絮凝过程中有机物的去除效果、形成絮体特性的差异以及温度的不同所造成超滤膜污染的主要机理。结果表明:微絮凝过程对低温水样的有机物去除率优于常温水样;尽管不同温度水样微絮凝过程中形成絮体的大小差异不大,但低温水样形成絮体的分型维数要明显小于常温水样,这说明低温水样形成的絮体结构更加疏松;不论是低温水样还是常温水样,滤饼层阻力都在造成膜污染的膜阻力因素中占主导地位,与常温水样相比,低温水样有较高的相对膜通量,说明低温水样形成的絮体造成的膜污染程度要比常温水样轻,这与低温条件下所形成絮体的特性密切相关。     

无纺布动态膜生物反应器处理生活污水的研究

采用无纺布动态膜生物反应器处理生活污水,考察了其对污水的处理效果,并对膜污染和膜阻力进行了分析.结果表明:无纺布动态膜生物反应器对COD和NH3-N有较好的去除效果,平均去除率分别为93%和90%;表面通量和透膜压力对膜污染影响显著,增加表面通量或透膜压力,将加快污泥颗粒在膜表面沉积速度,膜污染加剧,过滤阻力增加;无纺布过滤阻力主要来自泥饼层,约占总阻力的98%.     

陶瓷微滤膜过滤微米级颗粒体系的模拟

通过对陶瓷膜错流过滤微米级颗粒悬浮液过程中颗粒的受力分析,获得了可沉积在膜表面颗粒的临界粒径,结合传统的滤饼阻力模型,可获得膜表面污染层的阻力,从而计算出过滤过程的渗透通量.与实验结果相比,模型的模拟结果良好.     

无清洗重力驱动超滤工艺净水效能及机理

基于分散式供水及常规超滤工艺的不足,研发了重力驱动膜过滤工艺（简称GDM）,其结合生物滤饼层和超滤膜双重截留功效,兼具无清洗、无药剂、操作简单、低能耗、低维护等优点.采用GDM工艺净化河水、水库水、江水和模拟配水,长期运行其通量均可达到稳定状态,表明GDM工艺对不同类型的水源水具有普适性.原水水质、驱动压力、膜组件类型、膜材质、膜孔径大小、温度、间歇过滤、预处理等运行条件会影响生物滤饼层的结构和组成特性,从而影响GDM的稳定通量和膜污染特性.GDM工艺通量稳定性主要受生物作用调控的膜面生物滤饼层结构和组成特性影响,生物滤饼层结构越粗糙、孔隙越发达、胞外分泌物（EPS）质量浓度越少,稳定通量越高.相比常规超滤工艺,GDM膜面生物滤饼层可有效地强化对浊度、可生物同化有机碳（AOC）及氨氮等污染物的去除效能.此外,采用缓速滤池预处理工艺可有效地改善膜面生物滤饼层的结构特性,提高GDM稳定通量和污染物去除效能,研究成果有助于推动超滤技术在分散式供水领域中的应用.     

用超滤膜法浓缩剩余污泥中蛋白提取液的实验研究

采用超滤膜法浓缩剩余污泥中的蛋白提取液,并对浓缩过程中的膜污染展开分析,在此基础上,确定了污染膜适宜的清洗工艺．研究证明,采用超滤膜法浓缩剩余污泥中的蛋白质提取液是可行的．在室温条件下,操作压力为0．10～0．18MPa时,压力的升高有利于膜通量的增加,但也会增加膜污染的速率;浓缩过程中适当的清洗,不仅可以提高工作效率,还有利于膜通量的恢复;采用清水、碱性清洗剂（0．3％的NaOH和0．1％的NaCl0混合液）、酸性清洗剂（0．1％的盐酸溶液）,以动静态混合的方式清洗后,膜通量恢复率（WFR）可达到90％以上．     

膜污染中污泥层阻力模型及影响因素研究

膜污染是影响膜生物反应器大规模化应用的重要因素之一．优化了污泥层阻力的数学模型,并对污泥层阻力的影响因素进行了试验研究,模型确定了污泥浓度和膜面流速是引起污泥层阻力的主要因素．短期试验的结果较好地验证了污泥层阻力的数学模型,存在最佳的膜通量、污泥浓度和膜面流速．     

Characteristics of Membrane Fouling in an Anaerobic-（Anoxic/Oxic）^n-MBR Process

The characteristics of membrane fouling and cleaning, in a hybrid MBR process, was investigated. Under the condition of sub-critical flux operation, a characteristic three-stage trans-membrane pressure （TMP） profile is observed as time passes. The initially extended period of slow pressure rise, followed by a somewhat faster rise, is then sup- planted by a sudden transition to rapid pressure rise. Membrane cleaning experiments and SEM examination make it apparent that the rapid TMP rise is mainly caused by the accumulation of a surface cake layer, which is a reversible fouling that can be removed by tap water washing. Fouling caused by a gel layer, which is an irreversible fouling, can be removed efficiently by chemical cleaning. NaC10 can oxidize the gel layer, which is formed mainly of macromo-lecular organic substances. The HC1 can remove inorganic particles formed by Ca^2＋, Mg^2＋ ions etc. The sequence of chemicals used in membrane cleaning has an influence on the cleaning result. The effect of the NaC1O＋HC1 cleaning procedure is superior to that of the HCI＋NaC1O one. Particle size distribution measurements （PSD） reveal that fine particles are inclined to deposit or attach on the membrane surface, or in the membrane pores, and caused rapid fouling.     

分形理论在膜污染研究中的应用

近年来,膜生物反应器中膜污染的研究日益活跃,取得了较大的成果,并面临着突破性进展．分形理论使膜污染凝胶层微观结构的研究成为可能,为膜污染的研究提供了新的思路．本文对分形理论在过滤滤饼结构中的应用进行了较为全面的综述,并指出了其在膜污染研究中的应用前景．     

处理炼油厂“三泥”水相的陶瓷微滤膜再生方法的研究

采用反冲技术和化学清洗对过滤炼油厂“三泥”水相的陶瓷微滤膜进行再生。通过实验研究，确定了合适的清洗剂为加酶洗衣粉，清洗时间30min，清洗剂浓度8g/L，清洗进加压力为0．2MPa，周期为5min的低压脉冲，同时探讨了反冲对膜通量恢复程度的影响，确定了合适的反冲压力为0．5MPa。     

絮凝时间对混凝-超滤工艺的膜污染特性影响

为了考察混凝条件对混凝-超滤工艺中有机物去除效果和膜污染的影响,采用静态超滤试验装置对引黄水库水进行了试验研究。研究了絮凝时间对有机物去除效果、絮体特性和超滤膜过滤特性的影响,分析了膜污染的影响因素。试验结果表明：溶解性有机污染物质( DOC、UV254)的去除作用主要发生在快速混合和凝聚过程,后续的絮凝反应过程对溶解性有机污染物质的去除效果没有影响。絮凝反应时间对絮体特性和膜污染特性的影响显著,过短或过长的絮凝时间均会产生不利影响,絮凝时间10 min时絮凝指数处于最佳范围,絮体二维分形维数最小,膜比通量最大,膜总阻力最小,滤饼层阻力最小,膜孔阻力趋于稳定。混凝剂投加量为20 mg/L、絮凝10 min时,絮体特性和超滤膜过滤性能均达到最佳。欠投药和过投药都会对混凝效果、絮体特性和膜阻力特性产生显著影响。     

Fouling Characteristics and Prevention Techniques for Membrane Bioreactor

Membrane fouling is the main problem of membrane bioreactors (MBR), which seriously influences its wastewater treatment effect and running. The characteristics of microbiology and hydrodynamics concerning membrane fouling were investigated and the measure was put forward for optimum operation of MBR. The measure is that 1) the parameters of activated sludge concentration (X) and membrane flux should be lower than the critical values of X and membrane flux respectively, and 2) the activated sludge should be discharged periodically. The experimental results show that the combination backwashing of gas and permeated effluent is better than single gas backwashing or single permeated effluent backwashing. This technique can remove the cake layer deposited on the membrane surface, decrease the membrane fouling, and recover the membrane flux effectively. So it is effective for prevention of membrane fouling.     

Membrane fouling characteristics analysis of high concentration powdered activated carbon-microfiltration integrated system

The membrane fouling characteristics of high concentration powdered activated carbon-microfiltration (HCPAC-MF) integrated process are studied by comparing them with those of direct microfitration system using the particle counter,scanning electron microscope (SEM) and atomic force microscope (AFM). The results indicate that the specific flux of HCPAC-MF is 3 times better than that of the direct filtration process after the system is stabilized. The addition of HCPAC changes the particle distribution of raw water and influences the structure of surface fouling layer. The PAC with irregular shapes aggregating on the membrane surface makes the cake layer structure loose and increases the roughness of membrane surface,and this decreases the thickness of hydrodynamic boundary layer and the membrane resistance. After the physical cleaning,the membrane surface and pores are clean without any fouling matters aggregation,which illustrates that the cake layer of PAC can be formed quickly in this HCPAC environment and prevent the occurrence of irreversible fouling.     

纳滤处理腈纶废水的研究

采用纳滤设备对干法腈纶废水进行深度处理,考察了纳滤膜对COD、NH3-N及盐的截留率和脱色率的影响,操作压力和运行时间对渗透通量的影响。结果表明,经过纳滤技术处理后的水质COD截留率大于96%,NH3-N截留率大于95%,盐截留率大于94.5%,脱色率高达100%。纳滤膜的渗透通量随着操作压力的增大而增大,随着时间延长而下降。当操作压力为0.6 MPa时,纳滤膜的处理效果最好。该系统产水水质达到国家一级排放标准,并可以回用做工业用水。     

Supported liquid membrane extraction to treat coal gasification wastewater containing high concentrations phenol

The hollow fiber supported liquid membrane extraction was introduced to treat coal gasification wastewater to recover phenolic compounds,with tributyl phosphate (TBP) as carrier,kerosene as the membrane solvent,sodium hydroxide solution as the stripping agent and PVDF as the membrane material. Factors having strong impact on the extraction efficiency were studied in detail,including the mass transfer mode,twophase flow rate,stripping phase concentration. As extraction system with 20% TBP-kerosene,parallel flow mass transfer,stripping phase concentration 0.1 mol/L,the optimal operating conditions could be obtained. Under the optimum operating conditions,the time required to reach equilibrium for the extraction is 50 min, and extraction efficiency of phenol is 86. 2% and the phenol concentration of effluent is 98.64 mg/L.