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研究了膜生物反应器的运行效果、膜污染特征。结果表明:膜生物反应器具有良好的污染物去除效果,在处理生活污水时COD的去除草达到90%以上,出水COD控制在80mg·L^-1以下,NH4-N的去除效果能达到95%,出水NH4-N浓度10mg·L^-1以下,膜污染的过程呈现明显的“两段式”特点,即过膜压力缓慢上升阶段和快速上升阶段。采用NaOH+NaClO联合清洗后,膜的过膜压力迅速下降,表明膜污染以有机污染为主。 相似文献
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《分离科学与技术》2012,47(9):1317-1325
The impacts of aging and chemical cleaning on the properties and performance of ultrafiltration membranes in potable water treatment were investigated using membrane samples from a full-scale water filtration plant. A range of analytical tools were employed to characterize various membrane attributes, encompassing flux, tensile strength, morphology, surface resident functional groups, and both organic and inorganic foulants. The results of laboratory experiments that simulated chemical cleaning sequences were consistent with those observed in the full-scale water filtration plant, in terms of their effects on the properties of the membranes. It was revealed that aging played a significant role in the deterioration of the tensile strength of the membrane media, as well as the degradation of the intensity of surface resident functional groups, which led to the accumulation of foulants. While cleaning with hypochlorite resulted in a decrease of membrane tensile strength, identical cleaning with citric acid had no such effect. The degradation of membrane tensile strength may be correlated to a decrease in the intensities of functional groups as measured by Fourier transform infrared spectroscopy (FTIR). These results suggest that the concentration of hypochlorite and the cleaning duration should both be minimized to reduce their negative impacts on membrane properties. 相似文献
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无机膜分离技术是国际上最先进的分离技术之一,膜污染的清洗是膜应用过程中的一个重要问题。阐述了膜污染的性质,总结了膜污染清洗的各种物理方法和化学方法,并对无机膜材料的耐化学腐蚀性能进行了分析,为无机膜的应用维护提供了一定参考。 相似文献
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对超滤膜污染以及缓解膜污染的主要方法进行了综述,介绍了污染原因、主要污染物质、污染类型,叙述了膜前预处理、膜清洗、膜改性等当下为应对膜污染所采用的主要方法和紫外、外加磁场、电场等膜污染控制新方法,总结了从源头上控制膜污染的探索方向,认为超滤技术要在运行方式和工艺设计上做出更合适的选择,未来将向着低能耗、低药耗、自动化和... 相似文献
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《分离科学与技术》2012,47(4):571-580
The purpose of this study was to establish a rationale for the cleaning of microfilteration (MF) membranes fouled by milk. Milk was processed using a hydrophilic GVWP membrane. Fouling is the most important problem associated with the membrane-based milk sterilization process. This is mostly due to the deposition of bacteria, fats, proteins, and minerals on the membrane surfaces. In the first part of this work, the factors affecting the chemical cleaning efficiency were studied. This includes the effect of concentration, temperature, cleaning time, and cross-flow velocity. A wide range of cleaning agents including acids, bases, and surfactant was used. Flux recovery (FR) was employed for presenting the cleaning efficiency. In the second part of this study, FR was optimized using response-surface methodology with a face-centered central composite design (CCF). This was employed to create the mathematical model and minimize the number of experiments. 相似文献
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该文研究了平板膜污泥浓缩工艺中污染膜的清洗,分析了不同种类、不同浓度化学药剂的清洗效果,重点评估了膜通量恢复率、膜表面形态、临界通量等性能。结果表明Na Cl O为最有效清洗药剂,清洗后膜水通量恢复最显著,膜表面孔隙率恢复最高,Na OH药剂不适宜于该工艺中膜的清洗。此外,试验确定0.1%草酸和1%Na Cl O的组合清洗方式为污泥浓缩工艺中膜清洗的最佳清洗方式,经组合清洗后的膜表面形态基本完全恢复,临界通量可高达32~35 L/m2·h。 相似文献
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低压膜净水过程中的膜污染控制 总被引:1,自引:0,他引:1
近年来,低压膜(LPM)技术在饮用水处理和废水回用等领域的应用越来越广泛,但膜污染会消耗更多的能源,增加运行和维护费用,是制约其发展的瓶颈。膜前预处理技术与低压膜组合工艺已被广泛用在减轻膜污染、提高污染物去除率和膜通量等方面。膜前预处理技术可以改变水中分子与颗粒物的尺寸,影响污染物之间和污染物与膜之间的相互作用关系,抑制不良微生物的生长或去除可生物降解的污染物,从而影响膜过滤性能。此外,采用适当的操作方式(如运行方式,反冲洗,曝气)也可以有效地减轻膜污染。该文介绍了近年来国内外各种预处理技术和操作条件在控制低压膜污染的最新研究进展,并阐述了其在缓解膜污染方面的机理。 相似文献
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阐述了药厂冷却系统中沉积物的类型及产生的原因.介绍了化学清洗的优越性以及化学清洗工艺的实施过程.重点讲述了如何利用水封方法来实现对整个管网的分段清洗的原理和措施. 相似文献
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为考察水体中天然有机物(NOM)对纳滤膜性能产生的影响,以腐殖酸(HA)、牛血清蛋白(BSA)和海藻酸钠(SA)分别模拟水中常见NOM,腐殖质、蛋白质和多糖,对国产NF-1812纳滤膜进行单组分及其混合物定性定量有机污染及清洗实验。结果表明,有机污染造成膜通量下降,膜污染程度为SA>HA>BSA;NOM截留率可稳定在99.2%~99.6%;膜污染阻力主要为浓差极化阻力,其次是凝胶层阻力和内部污染阻力,有机污染液综合黏度和综合含量越大,浓差极化阻力的比例越高;对多组分有机污染膜进行错流速度9 cm/s的物理水力清洗和pH=10.0的质量分数分别为0.1%的NaOH+0.025%Na-SDS化学药剂清洗,膜通量、NOM截留率、苦咸水截留率、SEM成像均恢复至原膜状态,纳滤膜清洗效果良好,适用于中国西北苦咸水地区。 相似文献
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基于上海城镇污水处理厂AAO-MBR膜工艺长期运行中膜不可逆污染严重、离线化学清洗难以恢复理想通量的问题,对其清洗方式进行改进。在原清洗方式的基础上增加草酸二次清洗,探究污染膜产水能力恢复情况,并通过中试试验进行验证。结果表明:膜清洗方式改进后,离线清洗对膜污染物的去除更加彻底,清水通量可恢复至新膜的95.1%,较原清洗方式提高了27.2%。在相同通量下中试运行24 d后,膜运行压力比原清洗方式低18.2 kPa,膜污染速率明显减慢。研究通过改进MBR长期运行平板膜的污染物清洗方法,为今后MBR污水厂膜清洗提供参考,具有较好的工程指导意义。 相似文献
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