三种一体式MBR的膜污染趋势比较

对活性污泥—膜生物反应器、生物膜—膜生物反应器、复合式膜生物反应器的除污效果和膜污染趋势进行了研究。结果表明:活性污泥—膜生物反应器的膜污染程度最轻,膜通量下降速度最慢,膜污染也最容易消除;生物膜—膜生物反应器的膜污染程度最重,膜通量的下降速度最快;较大的曝气量可减轻膜的污染程度并减缓膜通量的下降速度。     

活性炭海绵动态膜生物反应器用于污水处理提标改造中试研究

自行设计研发了以活性炭海绵作为膜基材的动态膜生物反应器,为污水处理的提标排放及资源化利用提供了科学依据及实际参考价值。详细考察了该反应器对污染物的去除效果和运行特性,通过和现有污水处理厂处理效果比较,探索活性炭海绵基材动态膜生物反应器用于城市污水提标改造的可行性。结果表明,在水力停留时间8h、污泥浓度8 000mg/L的条件下,活性炭海绵动态膜生物反应器出水COD、NH3-N、TN和TP浓度分别≤35.0mg/L、≤1.4mg/L、≤10.2mg/L和≤0.3mg/L,出水达到《城镇污水处理厂污染物排放标准》GB18918 2002一级A标准。活性炭的吸附性能和海绵的空间结构特征协同作用强化了系统对污染物的去除效果,活性炭海绵动态膜生物反应器可完全取代现有污水厂深度处理工艺应用于提标改造。曝气反冲洗可有效减缓出水通量下降,使系统出水通量稳定在30L/(m2·h)左右。     

一体式膜生物反应器的在线反冲洗研究

介绍了采用在线空气反冲洗和在线清水反冲洗来解决膜生物反应器膜污染问题的试验研究。结果表明,采用在线空气反冲洗,当时间达80min后,膜生物反应器中的膜通量基本恢复至19L/m2·h以上,且反冲洗周期为6日;采用在线清水反冲洗,当时间达50min后,膜生物反应器中的膜通量基本恢复至19L/m2·h以上,反冲洗周期在11日以上。这种清洗程序和方法可指导膜生物反应器中膜污染的清洗,从而有效地控制膜污染。     

PAC-自生动态膜生物反应器处理生活污水的研究

向由孔径为56μm的普通工业滤布组成的膜生物反应器中投加不同量的粉末活性炭，对恒通量下的单周期运行情况进行了考察，并对被污染的动态膜表面和截面进行了扫描电镜观察。结果表明，较佳的PAC投量约为2g／L。在PAC投量为2g／L时，其运行周期（15d）为不投加PAC时（6d）的2．5倍，反应器中占优势的污泥平均粒径（100μm）也较不投加PAC时的（80μm）大。经扫描电镜分析可知，未投加PAC时膜孔隙间的凝胶层是造成膜污染的主要因素；投加2异／L的PAC时膜表面的滤饼层是造成膜污染的主要因素，其膜污染物易于清洗去除，经水力清洗和刷子刷洗后膜通量可基本恢复，再用0．5％的NaClO溶液浸泡12h后膜通量可完全恢复。     

SMSBR中PAC对膜污染的防治作用

在SMSBR处理焦化废水的过程中，通过向反应器中投加粉末活性炭（PAC）进而形成生物活性炭（BAC）来实现对膜污染的防治，并通过对BAC污泥的终端过滤来反映其对膜污染的改善作用。试验结果表明，BAC污泥在终端过滤过程中，其相对通量的变化规律与普通活性污泥相同，但投加PAC后的膜通量明显提高。另外，在相同压力下普通活性污泥的通量衰减指数要远高于BAC污泥，而在相同PAC浓度下BAC污泥的通量衰减指数随压力的变化与普通活性污泥一样，未表现出一定的规律性。BAC污泥的阻力分布表明，沉积层阻力仍占有绝对优势（大于80％），并随压力的升高而增大，但与普通活性污泥相比该比例有明显下降，膜的固有阻力所占比例明显提高，体现了PAC对膜污染的防治作用。     

膜生物反应器在污水处理中的研究进展

介绍了2004年6月在韩国汉城召开的“水环境一膜技术国际会议”(1wA Specialty Conferenee on Water Environment-Membrane Technology)情况及膜生物反应器在污水处理中的大规模应用，详述了膜污染防治和膜通量维持的措施以及膜污染的原因等，总结了近年来膜生物反应器在污水处理中的研究进展。     

MBR处理印染废水的膜污染及清洗研究

膜生物反应器（MBR）是一种新型反应器，处理印染废水时除污效果很显著，但长时间的运行会造成膜的严重污染，为此对A／OMBR（厌氧—膜生物反应器）处理印染废水时的膜污染情况和清洗效果做了研究。结果表明，膜污染主要是由膜表面凝胶层造成的；化学清洗的效果优于物理清洗（化学清洗能恢复膜通量约90％以上，而物理清洗仅能恢复膜通量约70％）；NaOH的清洗效果优于NaOCl。     

投粉末炭MBR处理微污染原水研究

采用投加粉末活性炭的膜生物反应器处理微污染原水，结果表明，对CODMn、氨氮和浊度的平均去除率分别为59．4％、93．5％和99．6％，出水水质与常规处理——臭氧活性炭工艺的大体相当，并且不需投加混凝剂，同时还减少了投氯量。     

投加粉末炭对SMBR过滤性能的影响

在相同的进水和运行务件下，考察和比较了生物活性炭一膜生物反应体系(BPAc—SMBR)与常规的活性污泥一膜生物反应体系(AS—SMBR)的膜过滤特性，并就粉末活性炭(PAC)对通量改善的相关机理进行了探讨。结果表明，添加1．2g／L的PAC可明显改善SMBR的过滤性能。与AS—SMBR相比。BPAC—SMBR的临界通量可提高32％；相同恒通量下的长期运行结果也表明BPAC-SMBR透膜压力的升高更为缓慢，其稳定运行周期可达到AS—SMBR的1．8倍；BPAC-SMBR的膜过滤总阻力比AS—SMBR的低约44％，其差别主要来自于滤饼阻力的减少。此外。还分析了混合液粘度、粒径分布等影响因素。     

MBR、MCR处理微污染水的膜污染比较

膜污染是影响膜反应器稳定运行的重要原因之一，为此考察了膜生物反应器(MBR)和膜混凝反应器(MCR)处理微污染地表水时的运行状况，并对膜比通量的变化进行了比较，发现MBR的膜污染情况比MCR的严重。MCR和MBR的膜组件经物理、化学清洗后膜比通量分别恢复至新膜比通量的99．7％和76．9％，物理清洗对此的贡献较大。经分析发现，MCR中无机污染占优势，主要污染元素是Fe；MBR中微生物和有机物是膜污染的主要组成，而无机污染物则主要是铁盐和磷酸盐。     

两种膜的前端处理技术减缓膜污染的试验研究

通过超滤膜过滤粉末活性炭预处理长江水和混凝沉淀预处理太湖水的上清液试验,比较各工艺中有机物极性含量的变化,结合膜的扫描电镜照片,探讨粉末活性炭和混凝沉淀预处理技术对膜污染的减缓作用。结果表明,疏水性有机物是造成膜污染的主要因素,亲水性有机物对膜污染的影响较小。超滤膜分别过滤经20 mg/L投量的粉末活性炭预处理的长江水样和25 mg/L投量的聚合氯化铝预处理的太湖水样时,相比直接过滤2种原水,超滤膜反洗后膜通量可有效恢复。粉末活性炭和混凝沉淀预处理后,膜表面形成的滤饼层较松散,易被周期性反洗排出膜组件,滤饼层可阻止疏水性有机物直接沉积在膜表面,减缓超滤膜污染,同时也可提高超滤膜出水的化学安全性。     

投加颗粒活性炭对膜生物反应器过滤特性的影响

膜污染是制约膜技术应用的重要因素。向膜生物反应器(MBR)中投加颗粒活性炭(GAC),通过分析MBR系统中膜通量、过滤阻力等的变化,考察投加GAC对MBR系统过滤特性的影响。结果表明,运行30d后,未投加和投加GAC的MBR系统的膜通量分别降至初始的31.3%和91.7%;未投加GAC系统的总过滤阻力和极化阻力分别为投加GAC系统的5.8和19.4倍,其污泥的多糖和蛋白质含量为投加GAC系统的近2倍,而其胶体物质和溶解性物质浓度分别为投加GAC系统的3.2和2.2倍。由此表明,投加GAC可大大减缓膜污染,延长膜的过滤周期。     

Membrane bioreactor process for removing biodegradable organic matter from water

This research investigated a membrane bioreactor (MBR) process for removing biodegradable organic matter (BOM) and trihalomethane (THM) precursors from pre-ozonated water. Bench-scale and mini-pilot-scale MBR experiments were conducted using powdered activated carbon (PAC) and acclimated biomass. Dissolved organic carbon (DOC) was removed through a combination of adsorption and biodegradation mechanisms, and the initial DOC removals depended on carbon dose, while steady-state removals were in the 20-60 percent range under various operating conditions. Both assimilable organic carbon (AOC) and total aldehydes were mostly removed to near detection limits and were not affected by PAC dosage. The AOC(NOX) removals were significantly higher than AOC(P17) or total AOC removals probably because the MBR microbial consortium was closer in characteristics to Aquaspirillum NOX than to Pseudomonas fluorescens (P17). The DOC was used instead of biodegradable organic carbon (BDOC) as a parameter for evaluating disinfection byproduct formation and bacterial regrowth potentials because BDOC assays did not yield consistent and conclusive results due to analytical difficulties. The removals of THM precursors were high when PAC was added; however, steady-state removals were a function of operating conditions and PAC dosage. Addition of PAC enhanced DOC removals and membrane permeate fluxes. Furthermore, pre-ozonation reduced membrane fouling and enhanced membrane permeate flux.     

纳米TiO_2改性膜生物反应器处理污水的研究

采用啧涂纳米TiO2的方法对聚偏氟乙烯（PVDF）微滤膜进行改性,用改性膜生物反应器（MBR）和非改性MBR处理污水,对比了两者的出水水质、膜通量和膜过滤阻力。结果表明,两套MBR的出水水质均可达到《生活杂用水水质标准》（CJ25．1—89）的要求;纳米TiO2改善了膜表面的亲水性和粗糙度,从而使改性MBR的清水膜过滤阻力和不同抽吸压力下的膜过滤阻力均低于非改性MBR的,而其在不同抽吸压力下的稳定膜通量则高于非改性MBR的。     

Membrane performance enhancer evaluations on pilot- and full-scale membrane bioreactors

Recently developed polymeric membrane performance enhancer product, MPE50, was tested in various pilot‐ and full‐scale membrane bioreactors (MBRs). The Initial MPE50 dosage was determined by visual jar tests and by using various bench‐top filtration tests. Different amounts of MPE50 were dosed, and the particle size and supernatant clarity of the mixed liquor were monitored visually. Bench‐top filtration tests were also conducted. A 50% higher MPE50 dosage is recommended to be added to the pilot/full‐scale bioreactors because, based on experience, some of the soluble microbial products in the mixed liquor do not completely react with polymer during the relatively short bench‐test mixing time interval. With the addition of 400 mg/L MPE50 to a pilot MBR, the design flow was increased twofold without any significant transmembrane pressure (TMP) increase for 1 day. The control TMP surged within a few hours without MPE50. Long‐term field trials in a full‐scale plant also showed a substantial flux increase. In addition to flux enhancement, MPE50 helped to remove foam from the bioreactors and improved plant aesthetics, safety and general operating performance.     

Novel electrokinetic approach reduces membrane fouling

An innovative submerged membrane electro-bioreactor (SMEBR) was built to reduce membrane fouling through a combination of various electrokinetic processes. The objective of this research was to assess the capability of SMEBR to reduce fouling under different process conditions. At the bench scale level, using synthetic wastewater, membrane fouling of the SMEBR was compared to the fouling of a membrane bioreactor (MBR) in five runs. Different protein concentrations in the influent synthetic wastewater were selected to develop different membrane fouling potentials: high (240 mg/l), low (80 mg/l) and zero protein addition. The MBR and SMEBR were operated at a flux equal to the membrane critical flux in order to create high fouling rate conditions. Membrane fouling rate, expressed as the change in the trans-membrane pressure per day (kPa/d), decreased in the SMEBR 5.8 times (standard deviation (SD) = 2.4) for high protein wastewater, 5.1 times (SD = 2.4) for low protein content, and 1.3 times (SD = 0.7) for zero protein, when compared to the MBR. The supernatant concentrations of the soluble microbial products (SMP) were 195–210, 65–135 and less than 65 mg/l in respective experimental series. Following the bench scale study, membrane fouling was assessed in a pilot scale SMEBR, fed with raw un-clarified municipal wastewater, and operated under real-sewage variable quality conditions. The pilot SMEBR exhibited three times smaller membrane fouling rate than the MBR. It was concluded that electrokinetic processes generated by SMEBR led to a reduction of membrane fouling through: i) removal of soluble microbial products (mainly protein and polysaccharides) and colloidal organic materials; ii) change of the structure and morphology of the suspended solids due their conditioning by DC field.     

MBR膜丝表面生物膜对出水水质的稳定作用

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.