颗粒活性炭干扰膜表面滤饼层形成的研究

向膜生物反应器（MBR）中投加颗粒活性炭（GAC）以干扰膜面滤饼层的形成,减轻膜污染与膜堵塞.结果表明,向MBR中投加粒径为40～60目的GAC（投量为1 g/L）,反应器运行21 d后,膜出水流量为初始时的52.9%,比对照试验的（30.8%）高22.1%;膜组件外层膜丝表面无滤饼层,内层膜丝间有滤饼层形成,部分GAC被吸附到滤饼层中从而增大了其孔隙率,提高了其透水率;GAC使滤饼层结构变得疏松而易于清洗,水力清洗后,在抽吸压力为0.02 MPa下膜清水通量可恢复到新膜的53.5%,比对照试验的高16%.     

优化恒压死端过滤方法筛选抗膜污染药剂

为研究采用恒压死端过滤方法初选MBR中抗膜污染药剂的可靠性,考察了在搅拌或不同曝气时间条件下,投加不同剂量高分子絮凝剂的活性污泥的静态过滤性能,确定了曝气10min为最佳扰动时间;同时表明,投加高分子絮凝剂可使污泥絮体尺寸增加、Zeta电位升高、上清液中的SMP浓度降低。另外,恒压死端过滤得出的絮凝剂最佳投加量为400 mg/L,这对减缓MBR的膜污染有积极的指导作用。在试验条件下,向MBR中投加400 mg/L的高分子絮凝剂,可使膜污染速率降为对照MBR的74.88%。     

PAC-UF组合工艺去除水中腐殖质类有机物效能及膜污染研究

研究了采用PAC-UF组合工艺处理含有腐殖酸的水时,PAC投加量对膜通量、有机物去除率和膜污染阻力的影响。结果表明,有机物去除率随PAC投加量的增加而提高;膜通量在低PAC投加量下得到提高,在高PAC投加量下降低;水中腐殖质类有机物主要造成不可逆膜污染;PAC投加量为20 mg/L时,能有效降低不可逆污染阻力,缓解膜污染。     

大型超滤水厂PVC和PVDF膜运行特性差异与优化

超滤技术已广泛应用于城镇给水处理厂,使得饮用水水质得到显著改善。不同材质超滤膜的运行周期、膜通量、跨膜压差(TMP)等的变化规律会有显著的差异,需要根据各自的特点对超滤系统进行运行参数调控与优化,以保证超滤系统的长期稳定运行。分析了山东某大型超滤水厂超滤系统长期运行的特点,对比了PVC膜和PVDF膜孔结构特征、膜通量、跨膜压差变化趋势及膜过滤阻力特性,调控和优化超滤系统运行参数,并进行了长时间的运行验证。结果表明,膜孔径和膜孔结构不同造成的膜污染是PVC膜与PVDF膜过滤特性差异的主要因素,恒定过滤周期运行模式下PVC膜通量加速衰减时段为82~220 min,造成PVC膜通量衰减了9. 14%,并形成了约5%的永久衰减膜通量,而PVDF膜的通量衰减并不明显,使得水厂超滤系统在恒定过滤周期(180min)运行模式下,出现了PVC膜的污染速率明显高于PVDF膜、系统的运行工况出现显著差异的现象。按照恒定过滤阻力模式运行时,PVC膜和PVDF膜的最佳过滤周期范围分别为82~108 min和96~155 min。水厂超滤系统在恒定过滤阻力运行模式下将PVC膜与PVDF膜在高温期和低温期的过滤周期分别调整为110、90 min和150、120 min,TMP的增长速率和化学维护清洗周期均基本一致,超滤系统实现了长期稳定运行。研究成果为我国超滤水厂中不同材质超滤膜的运行参数优化及协同稳定运行提供了参考。     

投加粉末活性炭对膜阻力的影响研究

小试和中试研究结果表明：粉末活性炭在膜生物反应器系统中具有改善泥水泥合液的性质和膜表面泥饼层结构的作用,从而减小了膜的过滤阻力,减缓了膜通量的下降。向膜生物反应器内投加粉末活性炭是提高和维持膜通量的有效途径,并且可以降低运行费用。     

混凝/PAC/超滤工艺去除水中天然有机物的研究

在饮用水处理过程中如何去除天然有机物是一个亟待解决的问题。混凝能降低水中污染物的浓度,避免这些物质进入膜孔内部,改善沉积在膜表面滤饼层的过滤性能和水中颗粒、胶体的迁移性能,提高膜通量。投加粉末活性炭(PAC)吸附溶解性有机物,利用超滤(UF)膜截留粉末炭,可达到提高出水水质的目的,还能防止膜污染。试验结果表明,混凝/PAC/UF组合工艺对水中UV254、UV410、TOC有较好的去除效果,平均去除率分别为92%、95%、84%,同时能改善膜透水通量、降低膜的吸附阻力、延长过滤周期、有效减少膜污染。     

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。     

不同MBR工艺处理生活污水效能的对比

污泥是富含有机物的碳质材料,可以制备成吸附性能比拟活性炭的吸附剂。利用污泥制备成廉价吸附材料并应用于膜生物反应器(MBR),对比研究了污泥基吸附剂-MBR(SAMBR)、MBR、PAC-MBR工艺处理生活污水的效能与膜污染情况。结果表明,SA-MBR工艺对UV254、DOC的去除率分别为58.5%与88.8%,与PAC-MBR工艺的去除效能(UV254:62.3%;DOC:90.1%)相近,优于MBR工艺的47.8%和85.9%。在控制膜污染方面,由于混合液中EPS与SMP的含量较低,而且投加的污泥基吸附剂富含铁、铝化合物,有效降低了污染物对膜的污染,使SA-MBR工艺的膜阻力较低,膜比通量下降速度较缓慢。     

臭氧预氧化/MBR工艺处理微污染原水的研究

采用臭氧预氧化/膜生物反应器(O3/MBR)工艺处理微污染地表水,通过30 d的稳定运行考察了系统的除污效能,并通过观察膜表面的微观形态对膜污染的机理进行了初步探讨。初始阶段向MBR中一次性投加2 g/L的粉末活性炭(PAC)作为生物载体,并控制水力停留时间(HRT)为0.5 h、臭氧投量为1.5 mg/L。结果表明,O3/MBR系统由于超滤膜的截留作用对颗粒物的去除非常有效,对浊度的平均去除率达到99.3%;对CODMn、DOC、UV254也有一定的去除效果,平均去除率分别为32.6%、18.7%和30.1%。尽管臭氧氧化使水中的AOC浓度有所增加,但经MBR工艺处理后,整个系统对AOC的去除率为13.4%,生物稳定性得到了提高。运行结束后的扫描电镜观察显示,超滤膜的膜孔被污泥层覆盖;通过原子力显微镜观察发现污泥层的表面粗糙不平,这两者均表明污泥层造成了膜污染。尽管该污泥层导致了跨膜压差的增加,但同时也起到了预过滤作用。     

臭氧对陶瓷膜去除地表水中有机物的影响研究

采用臭氧氧化技术改善陶瓷膜对钱塘江原水的处理效果,基于臭氧对膜出水中有机物的氧化作用,探讨不同的臭氧投加方式对陶瓷膜过滤特性的影响。结果表明,臭氧可较好地去除有机物,提高膜过滤通量。当臭氧投加量为5 mg/L时,对DOC和UV254的去除率可由未投加臭氧时的34%和22. 5%提高到44. 6%和40%;臭氧可有效提高陶瓷膜的膜通量,且随臭氧投加量的增加而逐步提高,臭氧投加量为5 mg/L时,膜比通量较未投加臭氧时提高了18. 3%;膜的化学清洗液的分析结果表明,臭氧氧化了污染陶瓷膜的一些有机物质,从而减少了膜污染,提高了膜通量。     

Enhancement of filterability in MBR achieved by improvement of supernatant and floc characteristics via filter aids addition

Reduction of membrane fouling in membrane bioreactors (MBR) by addition of three typical filter aids (aluminum sulfate (Al(2)(SO(4))(3)), polymeric ferric sulfate (PFS) and Chitosan) was investigated. The effects of filter aids on membrane pore blocking, gel layer and cake layer resistance were analyzed respectively. Significant improvement of the sustainable filtration was demonstrated in the filter aids added MBRs. The membrane fouling rate of the MBRs operated under 20L/m(2)h flux was in the order of Control MBR (no filter aid added)>Al(2)(SO(4))(3) added MBR>Chitosan added MBR>PFS added MBR. Membrane inner fouling due to pore blocking was analyzed by means of Fourier-transform infrared microscope (FTIR). Compared to the control MBR, significantly low protein and carbohydrate concentrations were measured in the membranes of the filter aids added MBRs, indicating that filter aids could effectively alleviate membrane pore blocking. Gel Permeation Chromatography (GPC) analysis suggested that both the concentration and molecular weight distribution of the macromolecules in supernatant play an important role in gel layer formation and loss of membrane porosity. The reduction of fouling rate in the filter aids added MBRs could be attributed to lower concentration and reduction in molecular weight of macromolecules in supernatant. The specific cake resistance (alpha(c)), mean floc size (d(p)) and fractal dimension of the flocs (df) in the filter aids added MBRs were also investigated. It was demonstrated that alpha(c) decreased with the increase of d(p) and with the decrease of df, which is in consistent with the model prediction.     

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。     

Novel magnetically induced membrane vibration (MMV) for fouling control in membrane bioreactors

Conventional submerged membrane bioreactors (MBRs) rely on the coarse bubbles aeration to generate shear at the liquid-membrane interface to limit membrane fouling. Unfortunately, it is a very energy consuming method, still often resulting in a rapid decrease of membrane permeability and consequently in higher expenses. In this paper, the feasibility of a novel magnetically induced membrane vibration (MMV) system was studied in a lab-scale MBR treating synthetic wastewater. The effects on membrane fouling of applied electrical power of different operation strategies, of membrane flux and of the presence of multiple membranes on one vibrating engine on membrane fouling were investigated. The filtration performance was evaluated by determining the filtration resistance profiles and critical flux. The results showed clear advantages of the vibrating system over conventional MBR processes by ensuring higher fluxes at lower fouling rates. Intermittent vibration was found a promising strategy for both efficient fouling control and significant energy saving. The optimised MMV system is presumed to lead to significant energy and cost reduction in up-scaled MBR operations.     

SMSBR处理焦化废水的膜污染机理研究

在采用SMSBR处理焦化废水的过程中，通过对污泥进行终端过滤来反映膜污染机理，着重考察了过滤过程中的阻力分布，并通过标准堵塞过滤定律和沉积过滤定律来拟合膜过滤过程，从而确定了膜污染的控制因素。污泥的阻力分布试验表明，沉积阻力占总阻力的90％以上，并随压力的升高而增大，而内部污染阻力所占比例最小；污泥的终端过滤过程严格符合沉积过滤定律，即使在过滤初期也不受堵塞过滤的控制，这与阻力分布的结果相对应；污泥在严格符合沉积过滤定律，即使在过滤初期也不受堵塞过滤的控制，这与阻力布的结果相对应；污泥在终端过滤过程中膜的相对通量随过滤时间呈指数衰减趋势，并在几分钟内就达到相对稳定值，且低压对应较高的相对通量，但通量衰减指数和压力之间没有相关性；污泥的压密指数为0．7015。     

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。     

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.     

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。     

膜法水处理技术的最新进展

详细介绍了2007年5月在英国Harrogate召开的“第4届IWA国际膜会议：膜法水与废水处理”的情况。对会议发表的宣读论文。从膜生物反应器、微污染水的低压膜过滤和NF／RO等方面进行了讨论，介绍了最近两年来国际上相关领域的最新研究进展。从此次膜会议来看，膜生物反应器尤其是好氧膜生物反应器仍是目前研究的热点，其中针对膜污染的机理、应对措施以及MBR节能降耗的研究最多，并取得了很多新的认识和切实有效的措施。