Relationship between sludge settleability and membrane fouling in a membrane bioreactor

The evolution of activated sludge settleability and its relationship to membrane fouling in a submerged membrane bioreactor were studied at a lab-scale equipment fed with synthetic wastewater. It was found that sludge volume index (SVI) gradually increased and the sludge settleability was reduced, which was caused by the propagation of filamentous bacteria. With increasing SVI, the average increasing rate of trans-membrane pressure increased, the stable filtration period was shortened, and the two stages (smooth stage and accelerating stage) of the trans-membrane pressure were more obvious. At the same time, the increasing rate of trans-membrane pressure at the smooth stage decreased and the rate at the accelerating stage increased with SVI, respectively. The observation by using scanning electronic microscopes showed the cake layer with loose structure and large thickness formed on the membrane surface due to the appearance of filamentous bacteria and high SVI in sludge. Influence of the sludge settleability on the trans-membrane pressure was related to the structure and thickness of the cake layer on the membrane. Translated from ACTA Scientiae Circumstantiae, 2005, 25(3): 396–400 [译自: 环境科学学报]     

膜堵塞机理研究与膜阻力测定

对膜污染堵塞机理进行了深入的研究 ,提出了膜内部的生物堵塞机理 ,指出膜表面的浓差极化、膜表面与膜孔内的污染、膜内部的生物堵塞是造成膜通量下降的主要原因。同时对膜阻力进行了测定 ,得出实验所用超滤膜组件的自身阻力Rm 为 5 4 4× 10 1 2 m- 1 ,膜污染产生的总阻力RZ 为 19 88× 10 1 2 m- 1 ,RZ 约是Rm 的 3 6倍 ,是导致膜通量下降的主要因素。     

浸没式平板膜生物反应器处理工业区污水试验研究

膜生物反应器(MBR)是膜技术和污水生物处理技术相结合的污水处理新工艺,近年来在城市污水和工业废水的处理中得到越来越多的关注。本试验采用浸没式平板膜生物反应器处理某城市工业区污水,并对该平板膜在运行过程中的膜污染情况进行试验研究,同时介绍其污水处理效果。试验表明,该MBR在次临界操作运行的情况下,以通量13L(m2·h)运行33d后,膜污染非常严重,将平板膜取出清洗后改以8L(m2·h)恒流运行,在此后60多d运行时间内,MBR系统保持稳定。同时,系统对该工业区污水CODCr、BOD5、NH3N和浊度的平均去除率分别稳定在80%、95%、90%和98%以上,但对总氮的去除效果一般,去除率只有50%～60%。     

缺氧/好氧膜生物反应器处理尿液污水的研究

采用缺氧/好氧膜生物反应器(A/O MBR)对尿液污水进行处理.结果表明:当进水NH 4-N、COD和BOD5分别为400～980(容积负荷为0.42～1.01 kg/(m3·d))、390～630和120～280 mg/L时,平均去除率分别为79.5%、75.1%和95.0%,同时系统对色度也有一定的脱除效果,经过A/O MBR和活性炭(PAC)处理后出水色度降为8倍;运行期间膜污染较严重,膜内表面微生物的滋生和膜外表面形成沉积层是造成膜污染的主要原因.     

漠-生物反应器混合液性质对膜污染影响的研究进展

膜-生物反应器作为一种新型的污水处理和回用技术。近年来在基础研究和实际应用领域都得到广泛关注，但是影响其长期稳定运行的膜污染问题却一直没有得到深入研究和解决。混合液特性是影响膜污染控制的重要因素。从混合液理化性质（组成、功能、结构和环境因素）和生物学性质（微生物群落结构、微生物功能特征）2个方面进行介绍，综述了目前关于混合液性质与膜污染关系的研究现状。目前的研究虽然取得一定进展，但在相关性分析、群落特征与膜污染关系、污染层形成机理等方面仍存在许多不足。     

典型有机物与超滤膜界面作用及膜污染机制研究

对二级出水中典型有机物的膜通量及膜污染变化情况进行分析比较,并应用扩展DLVO(x DLVO)理论分析了有机物超滤过程中的界面作用能对膜污染行为的影响机制.研究表明,海藻酸钠(SA)导致的膜通量下降最为显著,其次为腐殖酸(HA)和牛血清白蛋白(BSA);就3种有机物而言,膜污染均主要发生在粘附阶段,而在粘聚阶段中膜污染程度较小.对比而言,海藻酸钠(SA)主要形成可逆污染,腐殖酸(HA)和牛血清白蛋白(BSA)则以不可逆污染为主.在过滤过程中,极性界面作用能是控制膜污染的主要因素,HA和BSA的极性界面作用能为正值,能抑制膜污染,而SA的极性界面作用能为负值,会加剧膜污染.3种有机物在粘聚阶段的极性界面作用能均大于粘附阶段,说明粘附阶段的膜污染更严重.     

新型陶瓷平板膜MBR工艺在炼油废水处理中的应用

采用新型陶瓷平板膜MBR工艺处理实际炼油废水,考察了该工艺对COD、石油类物质的去除效果,同时研究了陶瓷平板膜在长期运行时的膜污染特性及膜清洗恢复情况,并探讨了陶瓷平板膜对石油类物质的抗污染性能。实验结果表明:陶瓷平板膜MBR工艺对炼油废水的处理效果较好,出水ρ(COD)<50 mg/L,ρ(石油类)<8 mg/L;长期运行时陶瓷平板膜跨膜压差(transmembrane pressure,TMP)呈现出"3阶段"变化趋势;滤饼层污染是造成陶瓷平板膜污染的主要因素;污染后的陶瓷平板膜经过物理化学清洗后基本可以恢复到新膜状态,不存在严重的不可逆污染,这表明陶瓷平板膜对炼油废水中的石油类物质具有较强的抗污染性能。     

Membrane fouling controlled by coagulation/adsorption during direct sewage membrane filtration (DSMF) for organic matter concentration

Unlike the role of the membrane in a membrane bioreactor, which is designed to replace a sediment tank, direct sewage membrane filtration (DSMF), with the goal of concentrating organic matters, is proposed as a pretreatment process in a novel sewage treatment concept. The concept of membrane-based pretreatment is proposed to divide raw sewage into a concentrated part retaining most organics and a filtered part with less pollutant remaining, so that energy recovery and water reuse, respectively, could be realized by post-treatment. A pilot-scale experiment was carried out to verify the feasibility of coagulant/adsorbent addition for membrane fouling control, which has been the main issue during this DSMF process. The results showed that continuous coagulant addition successfully slowed down the increase in filtration resistance, with the resistance maintained below 1.0 × 10¹³ m^− 1 in the first 70 hr before a jump occurred. Furthermore, the adsorbent addition contributed to retarding the occurrence of the filtration resistance jump, achieving simultaneous fouling control and chemical oxygen demand (COD) concentration improvement. The final concentrated COD amounted to 7500 mg/L after 6 days of operation.     

膜生物反应器处理酱油废水的试验研究

采用一体式膜生物反应器工艺处理酱油生产废水,探讨了进水COD、溶解氧、色度等工艺参数对系统处理效果的影响,并分析了膜污染问题.结果表明,系统具有较好的处理效果,当进水COD为505～1 209 mg/L、色度为180～200、浊度为251～471 NTU时,出水水质稳定,COD去除率平均达到90%,而色度、浊度的平均去除率也分别达到了79%和98%.在系统正常运行的2个月内,膜污染发展缓慢.     

MBR与SMBR脱氮除磷特性及膜污染控制

为提高污水深度处理效能和工艺运行的稳定性,研究以序批式膜生物反应器(SMBR)与传统膜生物反应器(MBR)为对象,对比研究其脱氮除磷特性、缺氧时间对工艺效率的影响及膜污染控制策略,同时应用分子生物学技术对两种工艺中微生物群落结构和组成进行分析.结果表明,间歇曝气能强化系统脱氮,使SMBR工艺去除总氮效果优于MBR,而在氨氮、总磷、COD、浊度去除方面两者无明显差异,去除率分别为94%、78%、80%、97%.延长SMBR工艺缺氧时间对COD、氨氮去除无显著影响,降低了总氮、总磷的去除率,总氮去除率由61%下降到46%,总磷由74%下降到52%.采用间歇曝气和投加一定浓度的粉末活性炭(PAC)均有利于减缓膜污染.微生物群落分析发现,两种工艺中微生物群落结构和组成无显著差异,硝化螺菌属(Nitrospira)和脱氯单胞菌属(Dechloromonas)为系统中的高丰度功能菌群,为工艺高效运行提供了生物学基础.