膜生物反应器处理工业废水中膜污染及膜过滤特性研究

采用膜生物反应器(MBR)中试试验装置处理制革、印染工业园区混合废水,考察了悬浮污泥浓度(MLSS)、溶解性微生物产物(SMP)和松散型胞外聚合物(EPS)表征总量、胶体粒子等因素对膜污染发生的影响程度.结果表明,试验装置启动后的120 d内,发生轻度膜污染现象,过滤膜阻力R20从1.5×1012m-1增加至1.8×1012m-1.MBR池内胶体粒子浓度与膜过滤阻力变化呈现明显的线性相关,而MLSS、SMP和EPS表征总量等因素的变化与膜过滤阻力的变化不存在相关性.分析认为胶体粒子是引起该试验装置发生膜污染现象的主要因素,其成因可能是胶体粒子通过附着在膜表面,沉积堵塞膜孔,从而造成膜污染.     

膜-生物反应器在我国的研究与应用新进展

膜-生物反应器(MBR)作为一种污水处理新技术,其研究和应用在我国受到了广泛关注.主要以1995-2006年发表在国内中文期刊上的关于MBR研究与应用的700多篇文献为基础,分析了与MBR构型、应用领域和研究机构等相关的文献数量分布,综述了在MBR新工艺、膜污染及其控制技术和污水处理类别等方面的研究进展,总结了MBR在污水再生利用中的应用概况,指出了未来MBR技术研究的挑战和工业应用的发展方向.     

ABR-MBR一体化工艺节能降耗措施优化研究

能耗高和膜污染是限制膜生物反应器(MBR)广泛应用的重要因素.为降低工艺运行能耗和延缓膜污染,以厌氧折流板反应器(ABR)-MBR工艺处理生活污水为例,对工艺结构和脱氮除磷运行条件进行优化.结果表明,通过优化ABR-MBR工艺结构,可降低43%的运行能耗,同时可保持较高的COD、NH+4-N、TN和TP去除效果,平均去除率分别为91%、85%、76%和86%.另外,添加颗粒填料可有效延缓膜污染,不过也改变了膜污染的形成过程,膜内部污染物含量显著增多,碳水化合物含量增加,而蛋白质含量减少,碳水化合物/蛋白质比明显增大.最终,增强了MBR反应器的实际应用性能.     

农副食品加工业高浓度废水的厌氧膜生物反应器技术

农副食品加工业COD年排放量在41种行业废水中排名第2,污染减排刻不容缓.农副食品加工业废水COD浓度高达8 000~30 000 mg·L-1,目前主要采用厌氧-好氧组合工艺处理,存在工艺流程长、管理难和成本高等问题.厌氧膜生物反应器(anaerobic membrane bioreactor,AnMBR)由于高效的膜与厌氧微生物协同作用,具有COD去除率高(92%~99%),COD负荷率高[2.3~19.8 kg·(m3·d)-1]等工艺特征,同时排泥少(SRT>40 d),基建成本低(HRT为8~12 h).根据高浓度COD的不同构成,COD甲烷化的限速步骤可分为水解酸化限速型、产甲烷限速型.AnMBR的膜污染特征及其控制比好氧MBR更为复杂和困难,现有膜污染控制措施包括错流过滤、曝气冲洗和膜松弛等.针对我国农副食品加工业高浓度废水达标排放的技术需求,AnMBR主要研究方向为提高COD去除率、控制膜污染和提高能源回收率,从而实现短流程厌氧的出水一步达标.     

旋转接头在MBR反应器改良中的应用研究

随着MBR反应器在国内污水处理行业中的不断应用,其重要性进一步得到了业界的认可。但是,如何消减运行过程中的膜污染问题,成为制约MBR推广和应用的重要因素。文章通过实验,将旋转接头应用在MBR反应器的改良中,重点研究通过旋转接头实现膜组件的旋转运行模式对膜污染的抑制效果。     

Influence of aeration intensity on the performance of A/O-type sequencing batch MBR system treating azo dye wastewater

Among the numerous parameters affecting the membrane bioreactor (MBR) performance, the aeration intensity is one of the most important factors. In the present investigation, an anoxic/aerobic-type (A/O-type) sequencing batch MBR system, added anoxic process as a pretreatment to improve the biodegradability of azo dye wastewater, was investigated under different aeration intensities and the impact of the aeration intensity on effluent quantity, sludge properties, extracellular polymeric substances (EPS) amount generated as well as the change of permeation flux were examined. Neither lower nor higher aeration intensities could improve A/O-type sequencing batch MBR performances. The results showed 0.15 m³·h⁻¹ aeration intensity was promising for treatment of azo dye wastewater under the conditions examined. Under this aeration intensity, chemical oxygen demand (COD), ammonium nitrogen and color removal as well as membrane flux amounted to 97.8%, 96.5%, 98.7% and 6.21 L·m⁻²·h⁻¹, respectively. The effluent quality, with 25.0 mg·L⁻¹COD, 0.84 mg·L⁻¹ ammonium nitrogen and 8 chroma, could directly meet the reuse standard in China. In the meantime, the sludge relative hydrophobicity, the bound EPS, soluble EPS and EPS amounts contained in the membrane fouling layer were 70.3%, 52.0 mg·g⁻¹VSS, 38.8 mg·g⁻¹VSS and 90.8 mg·g⁻¹VSS, respectively, which showed close relationships to both pollutant removals and membrane flux.     

序批式膜生物反应器同时脱氮除磷的比较研究

对比了厌氧-好氧(AO)及厌氧-缺氧-好氧(A²O)2种运行模式序批式膜生物反应器(SBMBR)对模拟生活污水同时脱氮除磷的性能.结果表明,2种运行模式的SBMBR对有机物及氨氮的去除率分别可保持在90%和95%以上.A²O MBR具有更强的释磷能力,其SPRR₃₀(前30min比释磷速率)比AO MBR高出47.5%;但SPUR₃₀(前30min比吸磷速率)却比AO MBR低,这是导致前者膜出水中TP值较后者高的原因之一.2个系统内污泥均有反硝化除磷能力,A²O MBR中DPAO(反硝化聚磷菌)的比例比AO MBR提高了57%;硝酸盐为电子受体时单位电子转移所吸收的磷,前者比后者高30%.这2个因素双重作用的结果导致了A²O MBR反硝化除磷能力的提高.A²O MBR系统曝气时间减半并没有加重膜污染,反而该系统的膜污染相对较轻.膜对有机物有较好的过滤截留作用,污泥沉降性能对SBMBR出水水质影响很小.     

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.     

膜生物反应器中膜污染机理和控制研究新进展

膜生物反应器(MBR)相比于传统活性污泥法具有出水水质好、设备占地面积小、剩余污泥产率低和便于自动控制等诸多优点,在污水处理和回用方面极具发展前景。然而膜污染是制约MBR广泛应用的最大障碍。文章着眼于总结MBR中膜污染机理和控制的研究新进展。介绍了MBR中膜污染的分类、污染机理和膜污染影响因素的研究概况,在此基础上,综述了MBR膜污染控制方法方面的进展,并对MBR中的膜污染机理和控制的研究发展方向做了展望。     

Shifts in microbial community structure and diversity in a MBR combined with worm reactors treating synthetic wastewater

The chemical oxygen demand (COD) and NH₃-N removal, membrane fouling, sludge characteristics and microbial community structure in a membrane bioreactor (MBR) coupled with worm reactors (SSBWR) were evaluated for 210 days. The obtained results were compared to those from a conventional MBR (C-MBR) operated in parallel. The results indicated that the combined MBR (S-MBR) achieved higher COD and NH₃-N removal efficiency, slower increase in membrane fouling, better sludge settleability and higher activities of the related enzymes in the activated sludge. Denaturing gradient gel electrophoresis was used to analyze the microbial community structures in the C-MBR and the S-MBR. The microbial community structure in the S-MBR was more diverse than that in the C-MBR. Additionally, the slow-growing microbes such as Saprospiraceae, Actinomyces, Frankia, Clostridium, Comamonas, Pseudomonas, Dechloromonas and Flavobacterium were enriched in the S-MBR, further accounting for the sludge reduction, membrane fouling alleviation and wastewater treatment.     

Anoxic gas recirculation system for fouling control in anoxic membrane reactor

Anoxic gas recirculation system was applied to control the membrane fouling in pilot-scale 4-stage anoxic membrane bioreactor(MBR). In the anaerobic-anoxic-anoxic-aerobic flow scheme,hydrophilic polytetrafluoroethylene(PTFE) membrane(0.2 μm, 7.2 m2/module) was submerged in the second anoxic zone. During 8 months operation, the average flux of the membrane was 21.3L/(m2·hr). Chemical cleaning of the membrane was conducted only once with sodium hydroxide and sodium hypochlorite. Dissolved oxygen(DO) concentration in the second anoxic zone was maintained with an average of 0.19 ± 0.05 mg/L. Gas chromatography analysis showed that the headspace gas in the second anoxic reactor was mainly consisted of N2(93.0% ± 2.5%), O2(3.8% ± 0.6%), and CO2(3.0% ± 0.5%), where the saturation DO concentration in liquid phase was 1.57 mg/L. Atmospheric O2 content(20.5% ± 0.8%) was significantly reduced in the anoxic gas. The average pH in the reactor was 7.2 ± 0.4. As a result, the recirculation of the anoxic gas was successfully applied to control the membrane fouling in the anoxic MBR.     

缺氧MBR-MMR处理海水养殖废水性能及膜污染特性

采用普通小球藻(C.vulgaris)作为实验藻种,搭建缺氧MBR-微藻膜反应器(缺氧MBR-MMR)耦合系统处理海水养殖废水,前置缺氧MBR用于有机物、NO~-_3-N和NO~-_2-N的降解,释放的NH~+_4-N进入MMR用于微藻生长而得到去除,考察协同处理效能和微藻采收情况,探究膜污染行为.反应系统共运行91 d,对NO~-_3-N和NH~+_4-N的去除率分别达到90.0%和88.0%以上,对PO~(3-)_4-P和TOC的平均去除率分别为49.4%和84.7%.普通小球藻在进行连续采收的情况下,能以平均浓度为9×10~7个·mL~(-1)的生物量稳定运行,实现了较好的去除效能和资源化利用.通过红外光谱和三维荧光光谱分析,MMR内造成膜污染的主要物质是色氨酸类蛋白质和腐殖酸类物质,与缺氧MBR内膜组件相比污染较轻.     

不同填料对减缓MBR膜污染影响的研究

膜生物反应器(MBR)由于存在膜污染问题,使水通过膜的阻力增加,过滤性下降,导致膜通量下降或跨膜压差升高,增加运行费用,限制了其进一步推广应用.通过向MBR中投加填料可以改善膜组件性能、优化系统运行条件以及改善混合液特性,从而减缓膜污染.重点分析了颗粒填料、悬浮填料和絮凝剂的投加对膜污染减缓的影响,进一步展望了可用于改善MBR系统填料的研发价值以及该工艺在污水处理和中水回用领域的良好前景.     

温度对膜生物反应器运行特性及膜污染的影响

温度对膜生物反应器（MBR）污染物去除效果和膜污染速率都有很大的影响。采用两套相同的MBR蓑置在冬季运行,其中一套维持20℃的恒温,另一套水温与周围环境相同。对两套装置处理效果及膜污染速率进行对比,并通过反应器中溶解性微生物产物（SMF）、胞外聚合物（EPS）含量、污泥粒径分布扣膜面污染物的比较,分析温度对MBR运行的影响。研究结果表明膜对污染物的截留能有效补偿低温时微生物作用的不足,因此低温对出水水质并没有显著的影响。此外,低温时虽然SMP和EPS的释放增加,但并没有引起膜污来的加剧。相反地,低温时污泥粒径较高温时小,而粒径较大的颗粒更易沉积于膜表面,因此低温时膜面固体物质含量较低,膜污染速率反而比高温时低。     

The effect of coupling coagulation and flocculation with membrane filtration in water treatment： A review

Water supply and sanitation demands are foreseen to face enormous challenges over the coming decades to meet the fast growing needs in a global perspective. Significant growth in the industry is predicted and membrane separation technologies have been identified as one of the possible solutions to meet future demands. Application and implementation of membrane technology is expected both in production of potable water as well as in treatment of wastewater. In potable water production membranes are substituting conventional separation technologies due the superior performance, potential for less chemical use and sludge production, as well as the potential to fulfill hygienic barrier requirements. Membrane Bio-Reactor (MBR) technology is probably the membrane process which has had most success and has the best prospects for the future in wastewater treatment. Trends and developments indicate that this technology is becoming accepted and is rapidly becoming the best available technology (BAT) for many wastewater treatment applications. A major drawback of MBR systems is membrane fouling. Studies have shown that fouling mitigation in MBR systems can potentially be done by coupling coagulation and flocculation to the process.     

正常污泥和膨胀污泥中EPS膜污染特性及其与膜表面作用能分析

胞外聚合物(Extracellular polymeric substance,EPS)是导致膜污染的重要物质,且不同形态污泥的EPS具有不同的性质,研究正常污泥和膨胀污泥的EPS膜污染特性具有重要意义.因此,实验考察了正常污泥和膨胀污泥的膜污染速率.结果表明,膨胀污泥膜污染速率远高于正常污泥,膨胀污泥EPS(Bulking sludge-EPS,BS-EPS)浓度((172.9±10.4) mg·g-1)明显高于正常污泥EPS(Normal sludge-EPS,NS-EPS)浓度((95.9±6 6) mg·g-1),且膨胀污泥的蛋白质/多糖(Protein/Carbohydrate,P/C)值(2.26)高于正常污泥的P/C值(1 97)此外,通过序批式吸附实验研究了正常污泥和膨胀污泥的EPS膜污染差异,并基于Derjaguine-Landaue-Verweye-Overbeek (XDLVO)理论计算了EPS与PVDF膜表面之间的作用能结果表明,EPS-膜系统的总界面能为负值,即EPS-膜系统之间会发生自吸附行为,而膜与BS-EPS的总界面能(-63.943mJ.m2)较膜与NS-EPS(-56.366 mJ·m2)具有较高的能量,因此,BS-EPS与膜的吸附力较强;NS-EPS和BS-EPS主要能量壁垒分别为8.89 kT和7.51 kT,表明NS-EPS与膜之间的排斥力更强,因而BS-EPS更容易造成膜污染     

Biological treatment of fish processing wastewater: A case study from Sfax City (Southeastern Tunisia)

The present work presents a study of the biological treatment of fish processing wastewa at salt concentration of 55 g/L. Wastewater was treated by both continuous stirred-ta reactor(CSTR) and membrane bioreactor(MBR) during 50 and 100 days, respectively. Th biological processes involved salt-tolerant bacteria from natural hypersaline environme at different organic loading rates(OLRs). The phylogenetic analysis of the correspond excised DGGE bands has demonstrated that the taxonomic affiliation of the most domin species includes Halomonadaceae and Flavobacteriaceae families of the Proteobacteria(Gamm proteobacteria class) and the Bacteroidetes phyla, respectively. The results of MBR w better than those of CSTR in the removal of total organic carbon with efficiencies from 97 to 98.6%. Nevertheless, salinity with increasing OLR aggravates fouling that requires m cleaning for a membrane in MBR while leads to deterioration of sludge settleability a effluent quality in CSTR.     

Biological treatment of fish processing wastewater: A case study from Sfax City (Southeastern Tunisia)

The present work presents a study of the biological treatment of fish processing wastewater at salt concentration of 55 g/L. Wastewater was treated by both continuous stirred-tank reactor (CSTR) and membrane bioreactor (MBR) during 50 and 100 days, respectively. These biological processes involved salt-tolerant bacteria from natural hypersaline environments at different organic loading rates (OLRs). The phylogenetic analysis of the corresponding excised DGGE bands has demonstrated that the taxonomic affiliation of the most dominant species includes Halomonadaceae and Flavobacteriaceae families of the Proteobacteria (Gamma-proteobacteria class) and the Bacteroidetes phyla, respectively. The results of MBR were better than those of CSTR in the removal of total organic carbon with efficiencies from 97.9% to 98.6%. Nevertheless, salinity with increasing OLR aggravates fouling that requires more cleaning for a membrane in MBR while leads to deterioration of sludge settleability and effluent quality in CSTR.     

Effects of protein properties on ultrafiltration membrane fouling performance in water treatment

Protein-like substances always induce severe ultrafiltration (UF) membrane fouling. To systematically understand the effect of proteins, regenerated cellulose UF membrane (commonly used for protein separation) performance was investigated in the presence of bovine serum albumin (BSA) under various water conditions. Results showed that although trypsin enhanced the membrane flux via proteolysis, catalysis took a long time. Membrane fouling was alleviated at high solution pH and low water temperature owing to the strong electrostatic repulsion force among BSA molecules. Both Na⁺ and Ca²⁺ could increase membrane flux. However, Ca²⁺ played a bridging role between adjacent BSA molecules, whereas membrane fouling was alleviated via a hydration repulsion force with Na⁺. The order of influence on membrane fouling was as follows: Ca²⁺ concentration > Na⁺ concentration > pH > temperature > trypsin concentration. Furthermore, a polyvinylidene fluoride UF membrane experiment showed that Ca²⁺ could reduce the fouling induced by BSA. Thus, the differences in UF membrane performance will have application potential for alleviating UF membrane fouling induced by proteins during water treatment.     

甲基异噻唑琳酮对MBR出水微生物生长分泌特性及群落结构的影响

污水再生处理反渗透(RO)工艺已在国内外获得广泛应用,但膜污堵问题阻碍RO工艺的进一步推广.投加非氧化性抑菌剂是控制RO膜生物污堵的常用手段,能够抑制细菌生长,但对细菌代谢产物分泌特性的影响尚不清楚.本课题的前期研究表明,细菌的胞外多聚物(EPS)是导致反渗透膜生物污堵的重要因素,细菌数量并非导致RO膜污堵的主要原因.针对上述问题,本文系统考察了典型非氧化性抑菌剂——甲基异噻唑啉酮(MIT)对RO系统进水(MBR出水)微生物的生长特性、群落结构及分泌特性的影响.研究发现,随MIT浓度增加,微生物生长迟滞期明显增长,但稳定期生物量增加;放线菌门、放线菌纲、类节杆菌属相对丰度明显增加;微生物分泌产物胞外多聚物(EPS)浓度增加,可能加重RO膜污堵潜势.上述结果表明,在污水再生处理反渗透系统中,MIT高浓度、长时间间隔的冲击式投加可能不利于膜污堵控制.