动态膜生物反应器用于污水处理的研究进展

动态膜生物反应器是近年来发展起来的高效废水处理工艺。该文介绍了国内外动态膜生物反应器的膜基材和动态膜的种类、形成机理,影响动态膜生物反应器过滤性能的因素,动态膜的清洗方法;并对今后的研究方向作了展望。     

自生动态膜生物反应器的研究进展

从膜过滤阻力角度,分析了自生动态膜的形成过程和形成机理;对自生动态膜组件形式和自生动态膜反应器进行了简单的分类;从曝气方式和强度、出水水头、污泥性质和膜基材特性4个方面分析了影响自生动态膜稳定运行的因素。虽然自生动态膜技术相比其他的水处理技术有巨大的优势,但该技术还尚未完全成熟,相关的研究工作还需要持续进行。     

DMBR运行过程及膜污染影响因素研究进展

动态膜生物反应器(DMBR)是一种具有广泛应用前景的污水处理新技术,与传统膜生物反应器(MBR)相比,处理效果相当且膜通量更高、膜污染更容易控制。简要分析了自生动态膜及预涂动态膜的形成过程和再生过程,并从膜材料、活性污泥的性质以及运行条件等方面综述了膜污染影响因素的研究进展,指出DMBR研究应用中存在的问题及发展方向。     

光催化协同TiO2动态膜去除水中腐植酸及膜污染特性

针对物理扰动模式控制动态膜污染使涂膜层脱落方面的局限性,提出光催化氧化技术协同动态膜降低膜污染,对比了陶瓷微滤膜、动态膜、光催化协同动态膜处理含腐植酸废水及含腐植酸/TiO₂混合废水过程中的膜通量、污染物去除率及膜污染阻力分布的变化趋势。结果表明:光催化协同作用可有效提高动态膜过滤腐植酸溶液过程中的膜通量、总有机碳(TOC)及UV₂₅₄的去除率,并同时降低可逆污染阻力及不可逆污染阻力,其中可逆污染阻力明显大于其他部分阻力,可逆污染是造成膜通量衰减的主要原因。光催化预处理时间越长,稳态膜通量、TOC及UV₂₅₄去除率增幅越显著,控制膜污染越有效。光催化预处理2h和8h再动态膜过滤时TOC去除率分别可达到80%和90%以上,UV₂₅₄去除率都可达95%以上。     

自组生物动态膜在污泥截留中的应用研究

在膜生物反应器基础上的自组生物动态膜反应器有其独特的性能。试验研究了 200 目不锈钢丝网为基材在曝气池内形成的生物动态膜的过滤性能,在普通混合液悬浮固体(MLSS)浓度约2200±200mg/L下,采用自流出水,考察了不同水头(Water Head)及初始通量对出水流量和SS的影响。结果表明:水头和初始通量对动态膜的形成具有关键作用,但同时对膜的堵塞也有相当大的影响。30cm是较好的操作水头,而初始通量小于0.62m/h时,基材上未形成有效的生物动态膜。试验中的通量高于0.1m/h,远远超过微滤膜生物反应器。     

动态膜技术的研究进展及其在冶炼行业中的应用前景

介绍了预涂动态膜技术的成膜机理,并论述了预涂剂pH值、浓度、温度、基质膜孔径、错流速率、跨膜压差等因素对动态膜形成和性能的影响,指出动态膜技术具有膜材料丰富、价格低廉、制作简单、抗污染能力强、出水量大、清洗再生方便等优良特性,在冶炼、化工等行业具有广阔的应用前景.     

动态膜生物反应器技术进展

该文介绍了动态膜生物反应器(dynamic membrane bio-reactor,DMBR)的成膜机理、膜结构形态、过滤模型及阻力特性,讨论了基网选择、污泥浓度(MLSS)、出水水头、错流速度对动态膜生物反应器运行特性的影响,对DMBR的应用前景进行了展望。     

Fenton试剂协同预涂动态膜处理乳化油废水

为减低预涂动态膜处理乳化油废水过程中的在线膜污染阻力,对Fenton试剂协同高岭土预涂动态膜处理乳化油废水特性进行了研究,考察了Fe2+/H2O2配比、溶液pH值及操作温度对减缓膜污染程度的影响。研究结果表明：投加Fenton试剂可明显地降低在线膜污染阻力,有效去除溶液及动态膜表面的污染物,CH2O2/CFeSO4最佳配比为1,其稳态膜通量是未投加Fenton试剂的3倍以上;Fenton试剂在酸性条件下减缓膜污染的效果较好,其中pH值为3时的稳态膜通量最高;最佳工艺操作温度为312 K,温度过高时尽管初始膜通量非常高,但稳态膜通量较低;原料液中油浓度越高,Fenton试剂对在线膜污染阻力的削减程度越小,投加和未投加Fenton试剂时达到稳态时的截留率相差在1%以内。     

陶瓷膜管外壁预涂动态膜形成特性研究

以错流外压方式在陶瓷膜管外壁面制备高岭土预涂动态膜,讨论了跨膜压差、涂膜液浓度、错流速度及操作温度对膜通量、涂膜量及吸附层与动态膜层阻力比的影响。结果表明:高错流速度下形成的动态膜层较密实,适合处理含细小颗粒物的废水;高压跨膜差下涂膜容易造成基膜的污染;低跨膜压差及高涂膜液浓度下需要较长的涂膜时间,跨膜压差在0.15~0.25MPa范围内较适宜;低涂膜液浓度下形成的动态膜层较薄,抗污染性能较差,涂膜液质量浓度在0.3~0.4g/L下较合适;升高温度易使高岭土颗粒物向陶瓷膜管外壁面沉积和孔内扩散,其中较大高岭土颗粒物更容易向陶瓷管外壁面沉积,形成较松散的动态膜层。     

陶瓷膜处理含有超细颗粒的乳化悬浮液时膜预处理工艺的研究

本文对陶瓷膜处理含有超细固体颗粒的乳化悬浮液时膜的预处理工艺进行了研究。通过对大孔陶瓷膜进行预处理形成动态膜来直接实现对含有超细颗粒乳化悬浮液的净化处理；用纳米级Al（0H）3粉体将原料液，配置成一定浓度的预处理液，对现有大孔膜进行预处理，形成动态膜实现了膜孔细化。系统探讨了操作工艺，如操作压力、膜面流速对动态膜形成及其稳定运行的影响，确定了形成动态膜的适宜的工艺条件，论证了动态膜具备较好的过滤分离性能。     

Effect of solution chemistry on membrane resistance and flux decline

Variations in the membrane resistance due to the adsorption of cakes of Glutamicum onto polysulphone membrane surface were evaluated by measuring the change in the permeation of pure water at constant pressure. Relations giving the membrane resistance as a function of contact time at varying bulk concentration, pH and ionic strength were obtained, by analogy with adsorption laws. Static (zero pressure) and dynamic (crossflow) experiments were then compared in order to determine the effect of convective flow and electrostatic interactions on cell adsorption, irreversible resistance and flux decline. Although convective forces tended to increase the amount of material accumulated near the membrane surface, it was electrostatic interactions that strongly affected cell adsorption and irreversible resistance, as evident in the irreversible adsorption and resistance results from the static and dynamic cases. Cell-cell interactions affect the porosity of the cake layer on the membrane, while cell-membrane interactions affect irreversible adsorption onto the membrane. Solution chemistry affects both types of interactions, as evident in the increased irreversible resistance of the cake layer and irreversibly adsorbed cells at the isoelectric point of cells (IEP). Additionally, the irreversible resistance of the fouled layer is dependent on its compactness, which is directly affected by solution chemistry. The flux decline rapidly decreased after the first 10 minutes of filtration. Flux decline is more pronounced at the IEP of the cell, also indicating that fouling and adsorption are strongly dependent on cell-cell and cell-membrane interactions.     

Water droplet dynamic behavior during removal from a proton exchange membrane fuel cell gas diffusion layer by Lattice-Boltzmann method

A major challenge in the application of proton exchange membrane fuel cells (PEMFCs) is water management, with the flooding of electrodes as the main issue. The Lattice-Boltzmann method (LBM) is a relatively new technique that is superior in modeling the dynamic interface of multiphase fluid flow in complex microstructures such as non-homogeneous and anisotropic porous media of PEMFC electrodes. In this study, the dynamic behavior of a water droplet during removal from gas diffusion layer (GDL) of a PEMFC electrode with interdigitated flow field is simulated using LBM. The effects of GDL wettability and its spanwise and transverse gradients on the removal process are investigated. The results demonstrate great influence of wettability and its spanwise and transverse gradients on the dynamic behavior of droplets during the removal process. Although increasing the hydrophobicity of GDL results in better droplet removal, its increase beyond a critical value does not show a significant effect.     

流体流动型态对膜通量影响的实验和计算流体力学研究

This paper reports a study on the role of fluid flow pattern and dynamic pressure on the permeate flux through a micro filtration membrane in laboratory scale. For this purpose, a dead-end membrane cell equipped with a marine type impeller was used. The impeller was set to rotate in the clockwise and counter clockwise directions with the same angular velocities in order to illustrate the effect of rotation direction on permeate flux. Consequently, permeate fluxes were measured at various impeller rotational speeds. The computational fluid dynamics (CFD) pre-dicted dynamic pressure was related to the fluxes obtained in the experiments. Using the CFD modeling, it is proven that the change in dynamic pressure upon the membrane surface has direct effect on the permeate flux.     

动态膜处理污水时阻力分布及污染机理

对高岭土动态膜处理污水过程中膜污染阻力分布及膜污染机理进行了研究。通过测定和计算得知不同操作条件下各部分阻力的比例及其变化情况。动态膜过滤污水的阻力主要由动态膜膜孔堵塞阻力和膜面污染层阻力所控制。随着错流速度的增大,总阻力减小,各部分阻力的比例有所变化,但动态膜膜孔堵塞阻力和膜面污染层阻力依然占主导地位。利用传统膜过滤时有关膜污染的堵塞模型和滤饼过滤模型对动态膜处理污水时的实验数据进行分析,结果表明,动态膜过滤污水过程中,过滤初期约10 min左右,污染以膜的微孔堵塞为主,此后,膜的污染情况因操作条件不同而有所差异,影响最显著因素为错流速度,当错流速度较小时,膜的污染以膜面沉积污染物为主,符合滤饼过滤模型。适当提高错流速度有利于减小过滤阻力。     

Removal of phosphorus from anaerobic membrane bioreactor effluent by ion exchange resin

The adsorption and regeneration mechanisms of phosphorus in anaerobic membrane bioreactor (AnMBR) effluent by anion exchange resins were investigated in this study. A strongly basic anion exchange resin (Amberlite IRA958) was selected due to its higher exchange capacity and antifouling performance. The effects of wastewater compounds, flow rate, and bed height of dynamic ion exchange column were determined. The dynamic ion exchange column exhibited stable treatment capacity and high exchange/regeneration capacity for phosphorus for long-term operation. However, humic acid could not be entirely regenerated by NaCl solution and the optimal regeneration protocol needs further investigations.     

Effect of Support Material Properties on Dynamic Membrane Filtration Performance

A dynamic membrane is defined as a cake layer which forms on a support material, for example, filter cloth or mesh when the liquid to be filtered includes suspended particles. Formation of an effective dynamic cake layer is highly related with the retention of particles on the support material surface. Therefore, support material properties are considered to be of prime importance in the performance of dynamic membrane treatment systems. This study investigates the effect of support material properties including pore size and structure of the material on dynamic membrane formation and performance. In this concept, a comparative evaluation was made between support materials which have different yarn types. The results showed that high total suspended solids removal efficiency (>98%) could be achieved by using dynamic membrane filtration technology. Mono-monofilament and staple filter cloths were determined as the most appropriate materials in terms of the critical fluxes which were 9.2 L/m² · h and 17–19 L/m² · h for mono-mono filament and staple materials, respectively. However, considering the results of more long-term experiments, mono-monofilament filter cloth was found more suitable for cake layer accumulation. Therefore, we postulate that mono-monofilament cloth can be used in dynamic membrane filtration systems as an alternative to traditional membranes in anaerobic membrane bioreactors.     

动态膜在错流微滤系统中的应用

利用6000目的高岭土作为动态膜涂膜材料,在相同的条件下过滤活性污泥和二级出水.实验结果显示,动态膜过滤在出水水质和通量方面明显优于直接过滤,而处理二级出水在膜通量方面没有优势.清洗实验结果表明动态膜能有效降低膜内部污染,并能恢复到新膜通量的90%.污泥浓度越大,通量越小.提高膜面流速和增加压力都能有效的提高膜通量,但提高膜面流速更经济.     

十二烷基-β-D-葡萄糖苷单层膜界面性质的分子动力学模拟

表面活性剂分子的界面组装结构是关系其应用性能的重要指标,分子动力学模拟是考察该体系性质的有力工具.采用分子动力学模拟方法研究了不同界面浓度下非离子表面活性剂十二烷基-β-D-葡萄糖苷的单层膜在水气界面的结构和动力学性质;通过密度分布、均方根位移曲线以及界面形成能等参数表征不同界面浓度条件下单层膜的结构及稳定性;并根据烷...