内置转盘式PVDF膜生物反应器污水处理的试验研究

对内置转盘式PVDF膜生物反应器(SRMBR)处理污水工艺及膜清洗进行了研究.SRMBR处理污水可以长期稳定运行,在实验模拟污水COD为180～368 mg/L时,出水COD在运行1d后稳定在20 mg/L以内,COD去除率>93%.增大转盘式平板膜组件转速可以增大SRMBR的平衡水通量,转速从15 r/min增大到25 r/min,平衡水通量从42.5 L/(m2·h)增大到47.5L/(m2·h).在一定自吸泵停抽时间内(0～1 min),延长停抽时间有利于减缓膜污染、提高平衡水通量.对污染的膜进行水洗、水洗 碱洗、水洗 碱洗 酸洗,3种清洗方式分别使膜平衡水通量恢复至新膜平衡水通量的48.4%、83.5%、90.2%.     

一体式膜-生物反应器中膜污染过程的动态分析

膜污染过程的动态研究对于有效地控制膜污染意义重大。结合膜过滤压差的上升和污染膜表面微观形态的变化 ,对不同污泥浓度和膜通量条件下 ,一体式膜 生物反应器中膜污染过程进行了动态分析。结果表明 ,膜污染初期主要是水中溶解性物质在膜表面附着 ,随后污泥在膜表面沉积。溶解性有机物在膜面的附着 ,对膜过滤压差即膜过滤阻力的变化影响不大 ,而活性污泥在膜表面的大量沉积将导致膜过滤压差迅速上升。污泥浓度愈高 ,膜通量愈大时 ,活性污泥颗粒愈易在膜面沉积。通过停止进出水维持空曝气、降低反应器内污泥浓度或延长膜的停抽时间可以使沉积在膜表面的悬浮污泥脱离膜表面 ,从而使膜过滤能力得到很好的恢复。采用经典的膜污染模型对各运行阶段膜污染模式进行了分析 ,模型拟合结果与电镜观察结果基本吻合。     

膜生物反应器同步硝化反硝化系统的研究

设计结构合理的膜生物反应器,驯化培养硝化污泥,复配反硝化细菌,构建了具有同步硝化反硝化功能且能去除COD的膜生物反应器系统.MLVSS的增高和污泥结构的改善为同步硝化反硝化提供条件.进水氨氮浓度在50 mg/L,MLVSS为8 g/L时,最佳HRT为4～6 h,气量控制在0.5 m3/h左右,TN去除率达80%以上.系统承受负荷变化范围0～0.36 kg N/(m3·d),TN去除率均能保持80%左右,COD去除率稳定在90%.系统投加粉末活性炭的方法可以改善污泥结构,进而减轻膜污染.在试验阶段内,添加了PAC的活性污泥MLVSS的高低对膜通量的影响不大,膜通量基本保持稳定.     

次临界操作下的膜污染机理研究

临界通量在膜污染控制的水动力学条件优化中是一个非常有意义的概念。本研究用一种新型的中空纤维膜组件过滤活性污泥混合液，采用通量阶式递增法对临界通量进行测定，实验表明，气水二相流是一个提高临界通量非常有效的方法，而且临界通量随着曝气强度的增大而增大，根据测定结果，可以得出膜生物反应器(MBR)的3个水动力学操作区：超临界区、临界区和次临界区。次临界操作可以防止颗粒物质在膜面上沉积引起的可逆污染，在次临界操作下，膜污染分为两个阶段，第一阶段为不可逆污染发展阶段，跨膜压力(TMP)发展缓慢；第一阶段膜的不可逆污染导致膜丝点通量不断的重分配，一旦出现膜丝上某一点的通量大于临界通量时，颗粒物质就以此点为突破口，不断沉积到膜丝表面，发生可逆污染，膜污染进入第二阶段，TMP急剧增加。     

不同氨氮浓度对混凝-超滤组合工艺水质处理效果及膜通量的影响

我国地表水源污染物中氨氮是普遍存在的,且难以处理,实验选择混凝-超滤组合工艺,腐殖酸为NOM的代表物,通过考察污染物中氨氮不同含量水平的变化,考察氨氮含量对出水水质、通量下降和污染类型这3个方面的影响。结果表明,在给定实验条件下,氨氮含量由0.1 mg/L增大至0.5 mg/L时,加快了污染物在膜表面的沉积,最终导致出水有机物含量降低。PVDF和PVC膜的TOC去除率分别提高17.31%和23.21%,UV254去除率分别提高2.78%和11.72%,膜组件通量分别下降了3.51%和10.17%。考察膜污染类型,发现氨氮促进了标准孔堵塞和滤饼层形成,同时削弱完全孔堵塞和中间孔堵塞。     

印染生化尾水反渗透深度处理工艺膜污染成因分析简

为阐明印染生化尾水反渗透膜处理时膜污染的成因,使用小试装置进行40 h膜污染实验,研究膜污染速率、污染程度以及可逆性,同时应用扫描电子显微镜-EDS能谱仪、傅里叶变换红外光谱仪、电感耦合等离子发射光谱仪、总有机碳测定仪等仪器对进水水质、膜表面污染物的形态和组成等进行表征。结果表明,膜表面主要是碳酸钙无机污染和钙与有机物络合污染,无机污染占主导,且可逆性差,有机污染物主要含有—OH和—CC官能团;单一去除废水中有机物污染物（TOC去除率达88%）对膜污染缓解不明显,但钙离子的去除可显著缓解膜污染,膜通量可增加72.6%;同时去除有机物和钙离子,膜通量可增加80.4%。     

次临界操作下的膜污染机理研究

临界通量在膜污染控制的水动力学条件优化中是一个非常有意义的概念。本研究用一种新型的中空纤维膜组件过滤活性污泥混合液 ,采用通量阶式递增法对临界通量进行测定 ,实验表明 ,气水二相流是一个提高临界通量非常有效的方法 ,而且临界通量随着曝气强度的增大而增大 ,根据测定结果 ,可以得出膜生物反应器 (MBR)的 3个水动力学操作区 :超临界区、临界区和次临界区。次临界操作可以防止颗粒物质在膜面上沉积引起的可逆污染 ,在次临界操作下 ,膜污染分为两个阶段 ,第一阶段为不可逆污染发展阶段 ,跨膜压力 (TMP)发展缓慢 ;第一阶段膜的不可逆污染导致膜丝点通量不断的重分配 ,一旦出现膜丝上某一点的通量大于临界通量时 ,颗粒物质就以此点为突破口 ,不断沉积到膜丝表面 ,发生可逆污染 ,膜污染进入第二阶段 ,TMP急剧增加。     

酒石酸钾钠（PST）对纳滤处理重金属废水的强化效果

以酒石酸钾钠（PsT）为络合剂,分别选取cd、zn、As和Ph4种金属废水,探索络合纳滤工艺对金属离子去除率和膜通量的强化效果,测定纳滤膜表面接触角以表征膜通量变化规律,并研究了压力、金属浓度和溶液pH参数对络合纳滤过程的影响。结果表明,PsT对4种金属去除的强化效果存在相似规律,分别有一个最佳PsT添加浓度。随PsT浓度的增加,金属离子去除率先增大后减小,而膜通量一直增大。研究发现,纳滤膜表面接触角与膜通量呈稳定的反比例关系,与金属离子种类和PsT添加量无关。随着操作压力的增大,膜通量线性增加,去除率基本不变;金属离子浓度的增加对膜通量影响不大,金属去除率略有上升;pH在4～5之间变化时,As去除中膜通量和去除率均有所升高,而cd、zn和Ph3种溶液处理效果基本不受pH影响。     

酒石酸钾钠(PST)对纳滤处理重金属废水的强化效果

以酒石酸钾钠(PST)为络合剂,分别选取Cd、Zn、As和Pb 4种金属废水,探索络合纳滤工艺对金属离子去除率和膜通量的强化效果,测定纳滤膜表面接触角以表征膜通量变化规律,并研究了压力、金属浓度和溶液pH参数对络合纳滤过程的影响。结果表明,PST对4种金属去除的强化效果存在相似规律,分别有一个最佳PST添加浓度。随PST浓度的增加,金属离子去除率先增大后减小,而膜通量一直增大。研究发现,纳滤膜表面接触角与膜通量呈稳定的反比例关系,与金属离子种类和PST添加量无关。随着操作压力的增大,膜通量线性增加,去除率基本不变;金属离子浓度的增加对膜通量影响不大,金属去除率略有上升;pH在4~5之间变化时,As去除中膜通量和去除率均有所升高,而Cd、Zn和Pb 3种溶液处理效果基本不受pH影响。     

水力停留时间对膜生物反应器复合工艺污水处理特性的影响

开发了厌氧-多级好氧/缺氧-膜生物反应器复合工艺,在不同水力停留时间(HRT)下,考察了系统对污染物去除效果及其膜污染的特性.结果表明,在试验选定的HRT范围内,系统对TN和TP的去除率随着HRT的降低而升高,当HRT为8.70、6.96、4.97 h时,系统对TN和TP的平均去除率分别为73.15%、79.76%、81.98%和67.79%、80.99%、92.16%.但是,较低HRT条件下膜通量较高,会加剧膜污染进程.解决这一问题的措施是增加膜组件个数,从而在不提高膜通量的情况下使系统保持较低的HRT,保证系统高效稳定的污染物去除效果.     

Fouling mitigation and cleanability of TiO<Subscript>2</Subscript> photocatalyst-modified PVDF membranes during ultrafiltration of model oily wastewater with different salt contents

In the present study, TiO₂-coated ultrafiltration membranes were prepared and used for oily water filtration (droplet size <?2 μm). The aim of this work was to investigate the effect of different salt contents on fouling and filtration properties of neat and TiO₂-coated membranes during oil-in-water emulsion filtration. The effect of the TiO₂ coating on the flux, surface free energy, and retention values was measured and compared with the neat membrane values. The cleanability of the fouled TiO₂-coated membranes by UV irradiation was also investigated by measuring flux recovery and contact angles, and the chemical changes during cleaning were characterized by ATR-IR. It was found that increasing the salt content of the model wastewaters, oil-in-water emulsions, increased the zeta potential and the size of the droplets. The presence of the TiO₂ coating decreases the membrane fouling during oily emulsion filtration compared to the neat membrane, due to the hydrophilicity of the coating regardless of the salt content of the emulsions. The neat and coated membrane oil retention was similar, 96?±?2%. The coated membrane can be effectively cleaned with UV irradiation without additional chemicals and a significant flux recovery can be achieved. Monitoring of the cleaning process by following the membrane surface wettability and ATR-IR measurements showed that the recovery of flux does not mean the total elimination of the oil layer from the membrane surface.     

Can Pickering emulsion formation aid the removal of creosote DNAPL from porous media?

The purpose of this investigation was to examine the proposition that creosote, emplaced in an initially water saturated porous system, can be removed from the system through Pickering emulsion formation. Pickering emulsions are dispersions of two immiscible fluids in which coalescence of the dispersed phase droplets is hindered by the presence of colloidal particles adsorbed at the interface between the two immiscible fluid phases. Particle trapping is strongly favoured when the wetting properties of the particles are intermediate between strong water wetting and strong oil wetting. In this investigation the necessary chemical conditions for the formation of physically stable creosote-in-water emulsions protected against coalescence by bentonite particles were examined. It was established that physically stable emulsions could be formed through the judicious addition of small amounts of sodium chloride and the surfactant cetyl-trimethylammonium bromide. The stability of the emulsions was initially established by visual inspection. However, experimental determinations of emulsion stability were also undertaken by use of oscillatory rheology. Measurements of the elastic and viscous responses to shear indicated that physically stable emulsions were obtained when the viscoelastic systems showed a predominantly elastic response to shearing. Once the conditions were established for the formation of physically stable emulsions a "proof-of-concept" chromatographic experiment was carried out which showed that creosote could be successfully removed from a saturated model porous system.     

不同来源高浓度有机废水的集中处理

按照水质情况,将多种来源于不同工业生产过程中的高浓度有机废水划分为高悬浮固体乳化液废水、难生化高浓度有机废水、高悬浮固体不含油有机废水、含铬有机废水和杂质含量较少的乳化液废水5类,分别采用酸化破乳/Fen-ton氧化/混凝/絮凝、Fenton氧化/混凝/絮凝、混凝/絮凝、还原/混凝/絮凝、震动膜过滤技术作为生化预处理技术,并通过小试和中试验证了各技术的效果。实验结果表明,按照上述分类结果,采用不同预处理技术可以得到良好的效果,废水水质明显改善,满足继续生化处理的基本条件。各预处理生产装置处理效果稳定,同时生化系统已经稳定运行120天以上,COD去除率超过90%,出水经过低剂量的Fenton试剂处理后可达到《污水排入城镇下水道水质标准》(CJ343-2012)。     

Parameters governing permeate flux in an anaerobic membrane bioreactor treating low-strength municipal wastewaters: a literature review.

The objective of this review was to conduct a comprehensive literature survey to identify the parameters that govern the permeate flux in an anaerobic membrane bioreactor (AnMBR) treating municipal wastewater. Based on the survey, research to date indicates that the optimal membrane system for an AnMBR consists of an organic, hydrophilic, and negatively charged membrane with a pore size of approximately 0.1 microm. The use of both external and submerged membrane configurations shows promise. The operating parameters that affect permeate flux in an external membrane system are transmembrane pressure (TMP) and cross-flow velocity. The operating parameters that affect permeate flux in a submerged membrane system are TMP, sparging intensity, and duration of the relaxation period. Both cross-flow velocity and sparging intensity impart a significant amount of shear force on the biomass in an AnMBR. High shear forces can reduce the microbial activity in an AnMBR. In addition, high shear forces can reduce the size of the biosolids in the mixed liquor and increase the release of soluble microbial products. In this respect, external and submerged membrane systems are expected to perform differently because the magnitude of the shear forces to which the biomass is exposed in an external membrane system is significantly greater than that in a submerged system. The size of the biosolid particles and concentration of soluble microbial products in the mixed liquor affect permeate flux. Higher concentrations of soluble microbial products may be present in the mixed liquor when an AnMBR is operated at relatively low operating temperatures. Aerobic polishing following anaerobic treatment can potentially significantly reduce the concentration of some components of the soluble microbial products in the mixed liquor. It is not possible to remove the foulant layer on an organic membrane with caustic cleaning alone. Acidic cleaning or acidic cleaning followed by caustic cleaning is required to remove the foulant layer. This suggests that both biological/organic and inorganic material contribute to membrane fouling.     

气-水联合反冲洗膜污染防治技术研究

采用气水联合反冲洗技术,考察了气水比(Qg/Ql)、反冲洗周期及其对膜污染的防治效果。结果表明,气水联合反冲洗较单独气或水反冲洗效果好;在过滤周期20min,反冲洗时间1min,气水比1.5时,气水联合反冲洗能够恢复膜通量到膜清水通量的80%以上。此法可大幅度清除沉积在膜表面的泥饼层,恢复膜通量,维持膜过滤性能的稳定,是一种较为有效的膜污染防治技术。     

膜生物反应器中膜的清洗方法和机理研究

研究了膜生物反应器处理盥洗废水时 ,水力清洗、酸洗、碱洗等不同组合形式对膜的清洗效果。结果表明 ,水力清洗可以较彻底地去除运行初期的膜表面沉积物 ,使膜通量有较大程度的恢复。对运行时间较长的膜来说 ,有机物和微生物是造成膜污染的主要原因。清水冲洗后用 0 0 5 %NaClO浸泡 1h ,再用 0 5 %的H2 SO4浸泡 1h是盥洗废水处理用膜有效的清洗方法 ,清水膜通量可恢复至 1 0 0 %。     

活性焦吸附对反渗透浓水膜蒸馏减排工艺的影响

本研究采用膜蒸馏(MD)技术,对煤化工废水2套处理工艺——(1)"混凝-超滤(UF)-反渗透(RO)工艺"和(2)"混凝-活性焦(AC)吸附-超滤-反渗透工艺"的RO浓水进行浓缩。通过对比分析MD的膜通量、产水水质以及膜污染等指标,重点考察AC吸附预处理对后续MD工艺的影响。结果表明,AC吸附作为前置膜处理工艺,可有效降低污染物在膜表面的沉积,减少膜润湿现象,并提高膜通量。GC-MS分析表明,AC能有效吸附废水中的酮类、醇类、酯类以及杂环类等挥发性有机物,降低MD过程中挥发至产水侧的有机物浓度,从而提高MD产水水质。     

超滤法预处理L-乳酸发酵液

以白酒酒糟乳酸发酵液为研究对象,采用截留分子量为100 kDa的中空纤维超滤膜（聚偏氟乙烯PVDF膜）去除其中的蛋白质等杂质,为后续电渗析分离提纯L-乳酸提供合格的料液。研究表明,操作压力、温度、pH值和进料速度对蛋白质截留率、乳酸回收率和发酵液的膜通量均有影响;乳酸回收率与蛋白质截留率基本呈负相关关系,是因为被截留的蛋白质等在膜面形成滤饼层,有吸附并截留乳酸的作用。通过单因素实验,确定了在操作压力为20 kPa,温度为27℃,pH为3.9,进料速度为280 mL/min的情况下处理效果最好,蛋白质截留率可达到98.01%,乳酸回收率可达到97.78%,发酵液的膜通量为7.26 L/（m2·h）。     

基于海水和盐田水的正渗透驱动液

采用海水和盐田水作为驱动液,研究正渗透过程中的通量变化和膜污染特征,探索其作为驱动液的可行性。结果表明,海水和盐田水含有大量的盐离子,具有高的渗透压,海水、2#、5#和9#盐田水与0.42、0.8、2.2和4.2 mol/L的氯化钠具有同样的通量行为。随海水和盐田水浓度增加,通量增加,同时污染也越严重。扫描电子显微镜观察和荧光光谱分析发现,盐田水中的硅酸盐和有机物会沉积在膜表面,引起比较严重的膜污染,尤其是高浓度的盐田水。海水和盐田水作为正渗透过程中的驱动液需要进行一定的预处理。     

超低压反渗透膜处理垃圾渗滤液运行工艺的实验研究

采用超低压反渗透膜处理垃圾渗滤液,考察不同工艺条件下膜通量、脱盐率、COD和NH3-N去除率的变化规律.实验结果表明,不同压力条件下对应某一输出频率存在最大膜通量.在输出频率变化方面,压力高的最大膜通量滞后于压力低的最大膜通量.运用变频调速技术,可实时解决操作压力与泵送流量的对应关系,确定最佳流量参数,提高反渗透系统运...