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MBR在净水工艺中的膜污染特征及清洗 总被引:12,自引:1,他引:12
采用悬浮生长型和两种附着生长型膜生物反应器(MBR)处理微污染源水,考察了各种MBR的膜污染特征及清洗情况。通过电镜观察污染膜表面,发现不同MBR的膜外表面污染特征不同,而膜内表面均无明显污染。对污染膜进行物理和化学清洗试验表明,常规物理清洗可使滤饼层大部分脱落,但对膜过滤性能的恢复效果较差;碱洗对膜过滤性能的恢复作用显著,有机污染对膜阻力的“贡献”最大。附着生长型MBR的污染膜表面粘性较大,常规物理清洗效果差,采用超声波清洗可使膜过滤性能恢复约30%,与超声波结合的化学清洗效果优于常规化学清洗。对膜污染化学洗脱液成分的分析表明,MBR中的膜污染与混凝一微滤膜组合工艺(C—MF)相比,有机污染物合量较高,Ca元素合量较低,腐殖质组分略高。两种工艺条件下洗脱液中溶解性有机污染物均以小分子有机物为主;与C—MF相比,NBR的膜污染洗脱液中大分子有机物增多,推测与反应器内微生物代谢产物的产生有关。 相似文献
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采用PVC新型材料MBR反应器处理模拟生活污水,控制其MLSS在4 500~6 500mg/L之间,探讨了出水抽停比和膜组件的放置方式对膜污染的影响。结果表明,当以12 min为一周期时,其最佳抽停比为9 min/3 min,这一模式是该新型材料MBR反应器的经济出水模式;当进行在线清洗时,膜组件水平放置的MBR反应器的膜污染速率为2.26 kPa/d,膜组件竖直放置的MBR反应器的膜污染速率为1.28 kPa/d;进行在线水洗和0.02%的次氯酸钠清洗,可有效降低膜污染速率,延缓膜污染,降低运行成本。 相似文献
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《Planning》2016,(3):36-41
膜生物反应器(MBR)结合了生物反应器有效去除有机物和膜分离组件高出水水质的优点,广泛应用于处理各种生活污水和工业废水,限制MBR进一步推广应用的主要因素是膜污染。膜污染造成水通量急剧下降和出水水质变差。MBR中膜污染的形成机理复杂,不仅与膜材料、膜孔大小、膜的疏水性和表面电荷等物理化学特性相关,而且和废水、污泥和上清液的特性有密切的关系。本综述从混合液悬浮固体浓度、污泥结构特点、上清液特征和组成成分及胞外聚合物等几方面对造成膜污染现象的机理进行分析总结,以找到制约和减少膜污染发生的具体方向。 相似文献
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《中国给水排水》2016,(23)
膜生物反应器(MBR)技术已在市政污水和工业废水等领域得到广泛应用,但膜污染始终是制约其稳定运行的关键问题之一,且随运行季节变化,其膜面污染物组成不同,清洗剂类型及清洗方案也存在差异。以处理实际生活污水的MBR为研究对象,在采用X射线能谱分析仪(EDX)分析不同季节污染膜表面元素组成的基础上,重点考察了碱洗、酸洗及其清洗顺序对清洗效果的影响。在秋季污染膜表面元素组成最为复杂,为有机和无机复合污染,无机污染元素中铁占比最高,达2.92%;次氯酸钠可有效清除膜表面有机污染物,而草酸去除无机污染物的效果较好;与先碱洗后酸洗相比,先2%草酸后0.3%次氯酸钠清洗的效果较佳,清洗后膜通量和平均孔径均得到较好恢复,膜表面元素组成与新膜的基本一致,仅发现C和F两种元素。 相似文献
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采用一体式聚丙烯中空纤维膜生物反应器处理模拟生活污水,考察了其处理效果,研究了运行条件对膜污染的影响和不同清洗方法对受污染膜的清洗效果。结果表明,在进水COD为172~331mg/L、NH3-N为23~27mg/L的条件下,稳定运行时系统对COD和NH3-N的去除率均大于90%。抽停比越小则膜通量的衰减越缓慢;抽吸压力越大则初始膜通量越大;试验中确定的最佳抽停比为8:2,临界抽吸压力为30kPa。对已污染的膜采用空曝气、水洗、水洗+碱洗、水洗+酸洗、水洗+碱洗+酸洗的方法进行清洗,可使膜通量分别恢复至新膜通量的30%、46.3%、86.54%、82.36%、92%。 相似文献
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通过搭建MBR膜性能评价平台,开展膜组件性能评估,以新型陶瓷平板膜为主体,与国内主导型膜材料产品进行性能对比研究,监测长期运行过程中膜通量变化、在线清洗频率、膜曝气强度、离线清洗周期等参数,并对膜的抗污染性能及陶瓷平板膜的清洗方式进行了分析。结果显示,在维持定期在线反冲洗、在线化学清洗的情况下,陶瓷平板膜的离线清洗周期大于6个月,形成的膜污染主要以对NaClO溶液更为敏感的有机物污染为主,而酸性清洗剂较易洗脱的无机物污染少;较高的清洗液温度、较长的浸渍时间,均有利于膜通量的恢复。将陶瓷平板膜用于实际工程中发现,出水COD和石油类物质均能达到回用水水质标准。 相似文献
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针对混凝沉淀预处理/膜生物反应器组合工艺,采用能谱分析和傅里叶红外光谱对膜表面的污染物进行分析,并对不同清洗剂的清洗效果进行了探讨。结果表明,酸性清洗剂对膜的清洗效果较好,膜表面的无机污染物基本被去除,但不能完全有效地去除膜表面的有机污染物;NaOH和NaClO的清洗效果不佳。从酸碱交替清洗效果来看,先酸洗后碱洗过程的膜恢复率比先碱洗后酸洗过程的高8%。对膜污染过程进行推测,胞外聚合物(EPS)和残留的絮凝颗粒一并沉积并吸附在膜表面,形成以有机物为主体、粘结性很强的凝胶层(内层);在混凝沉淀预处理长期运行条件下,凝胶层由内向外又不断吸附了无机盐类物质,凝胶层(外层)逐渐过渡为以无机污染为主,期间还存在无机物和有机物的络合,导致单纯采用碱和氧化剂的清洗效果不佳。 相似文献
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MBR膜丝表面生物膜对出水水质的稳定作用 总被引:6,自引:0,他引:6
在膜生物反应器(MBR)发生溶解性微生物产物(SMP)积累的情况下,对新膜与旧膜的出水水质进行了比较.结果表明,旧膜具有比新膜更为稳定和良好的出水水质,其出水平均TOC浓度为12.9 mg/L,低于新膜出水的36.8 mg/L,表明膜丝表面的生物膜强化了系统对SMP的截留能力.MBR上清液中分子质量>10 ku的大分子物质与分子质量<3 ku的小分子物质占有相当大的比例,旧膜对所有分子质量物质的截留效果均优于新膜.旧膜经清洗后,其出水的TOC浓度随着膜比通量的下降而降低. 相似文献
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Tze Chiang Albert Ng 《Water research》2010,44(7):2336-4671
The initial fouling characteristics of aerobic submerged membrane bioreactors (MBRs) were analysed under different flux conditions. Physico-chemical analyses of the mixed liquor hinted that carbohydrates were more important to membrane fouling than proteins. However, this contrasted with the characterisation of foulants on the membrane surfaces. Micro-structural analyses of the foulants on the membrane surfaces showed that the dominant foulants were different under different flux conditions. Membrane fouling occurred through a biofilm-dominated process under lower flux conditions, but the mechanism shifted towards a non-biofilm, organic fouling process as the flux was increased. In spite of the differences in fouling mechanisms, it was found that the protein fraction on the membrane surfaces, in the initial stages of MBR operations, had the greatest impact in the rise of transmembrane pressure. 相似文献
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膜混凝反应器处理滦河水中试研究 总被引:3,自引:0,他引:3
采用膜混凝反应器(MCR)对滦河原水进行中试研究,重点考察了对污染物的去除效果、膜污染及清洗方式。结果表明:MCR工艺的出水水质符合《城市供水水质标准》(CJ/T206—2005)的要求;在高温、高藻期投加4mg/L三氯化铁后,对CODMn的去除率为44.6%,若同时投加2mg/L的有效氯,则可使对CODMn的去除率提高到53%,且进水水质波动较大时出水水质仍保持稳定;该工艺对浊度、细菌有很好的去除效果;当膜在较高通量下运行时,采用化学在线清洗(即EFM操作)可有效清除膜污染物质,及时恢复膜的过滤性能。 相似文献
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Fouling characteristics of NF and RO operated for removal of dissolved matter from groundwater 总被引:6,自引:0,他引:6
A pilot study had been performed for about 6 months in order to investigate the removal efficiency of dissolved matter and its fouling potential during nanofiltration (NF) and reverse osmosis (RO) of local groundwater that was pretreated with an ultrafiltration (UF) membrane system. After pilot plant operation, autopsy tests were performed to identify the characteristics of foulants that were attached to the membrane surface. In the autopsy tests, the flux recovery for each specific cleaning scheme (hydraulic washing, acid cleaning, and alkaline cleaning) was also measured using a dead-end filtration cell unit. The washing solution used in each chemical cleaning was analyzed to identify major components of the foulants, and the membrane surface was observed using the scanning electron microscopy (SEM).Among three kinds of membranes tested, one NF and two RO membranes, the NF and RO1 membranes showed a rapid flux decline after 100 days of operation. Especially, the RO1 membrane showed the more serious flux decline than the NF membrane. The RO2 membrane, with the lowest recovery rate, demonstrated a gradual flux decline. The removal efficiency of dissolved inorganic matter (as conductivity) for each NF, RO1 and RO2 membrane was 76.3%, 88.2% and 95.3%, respectively. The removal of dissolved organic matter (as total organic carbon) was found to be about 80% for both NF and RO membranes used in this study. During the membrane autopsy tests, five sections of the fouled membrane were cut along each NF and RO membrane module from the feed inlet side to the concentrate outlet side, the specific flux for each membrane section was measured before and after each cleaning step. As expected, the degree of fouling was intensified along the membrane surface as the feed flow approached the outlet. Based on the analysis results of wash water used in each cleaning step, the major foulants attached to the membrane surface appeared to be Ca bound with inorganic matter and Si bound with organic matter. Fe seemed to be a great contributor to irreversible fouling. The SEM analysis indicated that the organic matter was forming the first fouling layer close to the membrane and that the inorganic matter was layered top of the organic fouling layer in a tetragonal shape. Any evidence of biofouling was not observed in this study because most of microorganisms had been already removed by the UF pretreatment. 相似文献