共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
膜污染是膜生物反应器(MBR)运行的必然结果,是MBR大面积推广的严重阻碍,因此研究膜污染控制技术具有重要意义。从膜污染发生前的预防和膜污染发生后的清洗2个方面,论述了常见的各种膜污染控制手段,综述了膜污染控制技术的研究现状与进展。其中膜污染的预防手段主要有膜(膜组件)固有性质的改进、操作条件的优化以及混合液性状的调控3类,而膜污染的清洗手段按是否使用药剂可分为物理清洗和化学清洗2类。综合考察MBR运行中的膜污染状况,采用合理的方法对膜污染进行控制,能够有效延长膜的使用寿命,提高MBR的实用性能。 相似文献
3.
BQ Liao LJJ Catalan IG Droppo SN Liss 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2004,79(12):1342-1348
The effects of sodium hypochlorite (NaOCl) on sludge properties and membrane permeate flux were studied using a pressurized stirred ultrafiltration cell. Oxidation with NaOCl resulted in sludge solubilization and decreased sludge floc sizes. The sludge dissolution constant was estimated at 0.3 ± 0.1 mg sludge mg?1 free chlorine under testing conditions. The increases in soluble chemical oxygen demand and total carbohydrate concentration in centrifuged supernatant were less than proportional to chemical dosage. Membrane permeate fluxes were much lower as a result of oxidation. Soluble biopolymers accounted for more than 76% of the total hydraulic resistance during ultrafiltration of oxidized sludge. By contrast, both the settleable sludge flocs and the soluble biopolymers were important contributors to the hydraulic resistance of sludge before oxidation. Given the benefits of NaOCl solution for membrane cleaning and its negative impact on sludge properties, the quantity of NaOCl solution used for maintenance cleaning of membranes should be optimized. Copyright © 2004 Society of Chemical Industry 相似文献
4.
5.
MBR膜的污染及其清洗技术研究进展 总被引:8,自引:0,他引:8
针对环境污染控制中广泛应用的膜生物反应器(MBR),阐述了其污染的主要来源和影响因素,重点介绍了膜清洗的几种方法及发展状况,并提出了膜清洗技术的发展方向。 相似文献
6.
7.
Microporous polyethylene (PE) hollow fiber membrane with a porosity of 43% and N2 permeation of 4.96 cm3 (STP)/cm2 s cmHg was prepared by melt‐spinning and cold‐stretching method. It was found that PE with a density higher than 0.96 g/cm3 should be used for the preparation of microporous PE hollow fiber membranes. By increasing the spin–draw ratio, both the porosity and the N2 permeation of the hollow fiber membranes increased. Annealing the nascent hollow fiber at 115°C for 2 h was suitable for attaining membranes with good performance. By straining the hollow fiber to higher extensions, the amount and size of the micropores in the hollow fiber wall increased, and the N2 permeation of the membranes increased accordingly. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 203–210, 2002; DOI 10.1002/app.10305 相似文献
8.
Performance evaluation and antifouling analyses of cellulose acetate/nanodiamond nanocomposite membranes in water treatment 下载免费PDF全文
In this study, nanocomposite membranes based on cellulose acetate (CA) and nanodiamond (ND) were prepared by applying phase inversion methods. In order to achieve efficient dispersion and more hydrophilic NDs, they were functionalized via heat treatment (ND‐COOH). The prepared nanocomposite membranes were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), contact angle, porosity measurement, tensile strength, and abrasion resistance techniques. Furthermore, the governing fouling mechanisms were determined by using classic models as well as combined fouling models. Moreover, the effect of precoagulation with polyaluminum chloride (PAC) on the humic acid (HA) filtration was investigated. The obtained results showed that in the presence of ND‐COOH, the abrasion resistance of nanocomposite CA membrane was three times higher than that of pristine CA membrane. Besides, the nanocomposite membranes with 0.5 wt % of raw and functionalized ND exhibited excellent hydrophilicity and PWF. The analysis of fouling mechanism based on Hermia's model revealed that the cake formation is prevailing mechanism for CA and CA/ND (0.5 wt %) membranes while for CA/ND‐COOH (0.5 wt %) membrane, experimental results are fitted by combined cake filtration‐complete blocking (CFCB) model. It confirms that pretreatment with PAC can significantly mitigate fouling and improve HA removal. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44873. 相似文献
9.
Yan Zhao Yangbo Qiu Natalie Mamrol Longfei Ren Xin Li Jiahui Shao Xing Yang Bart van der Bruggen 《Frontiers of Chemical Science and Engineering》2022,16(5):634
Discharged hospital wastewater contains various pathogenic microorganisms, antibiotic groups, toxic organic compounds, radioactive elements, and ionic pollutants. These contaminants harm the environment and human health causing the spread of disease. Thus, effective treatment of hospital wastewater is an urgent task for sustainable development. Membranes, with controllable porous and nonporous structures, have been rapidly developed for molecular separations. In particular, membrane bioreactor (MBR) technology demonstrated high removal efficiency toward organic compounds and low waste sludge production. To further enhance the separation efficiency and achieve material recovery from hospital waste streams, novel concepts of MBRs and their applications are rapidly evolved through hybridizing novel membranes (non hydrophilic ultrafiltration/microfiltration) into the MBR units (hybrid MBRs) or the MBR as a pretreatment step and integrating other membrane processes as subsequent secondary purification step (integrated MBR-membrane systems). However, there is a lack of reviews on the latest advancement in MBR technologies for hospital wastewater treatment, and analysis on its major challenges and future trends. This review started with an overview of main pollutants in common hospital wastewater, followed by an understanding on the key performance indicators/criteria in MBR membranes (i.e., solute selectivity) and processes (e.g., fouling). Then, an in-depth analysis was provided into the recent development of hybrid MBR and integrated MBR-membrane system concepts, and applications correlated with wastewater sources, with a particular focus on hospital wastewaters. It is anticipated that this review will shed light on the knowledge gaps in the field, highlighting the potential contribution of hybrid MBRs and integrated MBR-membrane systems toward global epidemic prevention. 相似文献
10.
以碳酸钙悬浮液、活性污泥混合液及蛋白溶液作为过滤介质,采用标准堵塞过滤和沉积过滤数学模型预测3 h内膜污染类型,结合膜孔径分布、过滤介质粒径分布和污染阻力分布,研究同质增强型聚间苯二甲酰间苯二胺(PMIA)中空纤维超滤膜污染机理。将同质增强型PMIA中空纤维膜应用于MBR系统处理城市生活污水,监测其长期运行的出水水质;借助场发射扫描电镜和特征X射线能谱仪对比分析水洗和化学清洗效果。研究结果表明,当过滤介质为蛋白时,t-t/V线性相关系数为0.9940,膜污染符合标准堵塞模型;当过滤介质为碳酸钙悬浮液和污泥混合液时,V-t/V线性相关系数分别为0.9733、0.9994,二者较为符合沉积模型。应用于MBR中的同质增强型PMIA中空纤维膜对COD、NH4+-N、TP的平均去除率分别为97.78%、96.71%、49.81%,出水水质较好。经化学清洗后膜表面元素接近于原膜,清洗效果较佳。 相似文献
11.
膜生物反应器中膜污染影响因素的研究进展 总被引:1,自引:1,他引:1
文章综述了膜生物反应器(MBR)运行过程中膜污染影响因素的研究现状和进展。膜污染会导致膜通量下降、系统运行成本增加等问题,是限制MBR进一步发展的瓶颈。从膜元件固有性质、膜分离操作条件以及活性污泥混合液性状等3个方面,分析了影响膜污染发展的主要因素,论述了各因素与膜污染的具体关系。各因素之间互相作用,直接或间接影响膜污染,其中膜材质、膜孔径、膜通量、曝气量、污泥组分、粒径分布(PSD)、胞外聚合物(EPS)、溶解性微生物产物(SMP)等为重要影响因素。 相似文献
12.
膜生物反应器(MBR)在污水处理领域的应用日益广泛,填料的投加对MBR污水处理效率和膜污染进程有一定的影响。本文分别向MBR中投加不同量的软性和硬性悬浮填料,研究了悬浮填料对MBR运行效率及膜污染的影响。结果表明,投加填料后MBR对COD、氨氮和总磷等污染物的处理效率有所提高,明显减缓了膜污染的进程。软性填料对MBR的改善效果优于硬性填料,投加20%的软性填料时,系统对COD、氨氮和总磷的去除率分别可达96.53%、98.21%和52.75%,系统运行30天时的膜污染情况比未投加填料的系统减缓了41.43%。通过对比发现软性填料能够为微生物提供更大的生存空间,提高反应器内的微生物量,从而提高MBR对污水的处理效率同时改善膜污染,是一种加强MBR系统的适宜填料,最佳投加量为反应器有效体积的20%。 相似文献
13.
14.
Joonghwan Mo Seung‐Hee Son Jonggeon Jegal Jaephil Kim Yong Hwan Lee 《应用聚合物科学杂志》2007,105(3):1267-1274
A polyamide (PA) nanofiltration (NF) composite membrane with TiO2 layers was designed and prepared, in which the TiO2 layers were chemically linked to the crosslinked polyamide layers of the membrane. In this study, TiO2, one of the well known photo‐catalysts effectively degrading organics with UV light, was introduced to the PA NF membrane by using 3‐aminopropyltrimethoxysilane (APTMOS), titanium (IV) isopropoxide (TIP) to improve its antifouling property. In particular, for this membrane, SiO2 layers were formed between the TiO2 layer and the crosslinked polyamide layer of the membrane to protect the organic parts of the membrane from the TiO2 catalyzed UV degradation. The prepared membrane with TiO2 layers was then characterized using several analytical methods: scanning electron microscopy (SEM), X‐ray photoelectron spectroscopy (XPS), x‐ray diffraction (XRD) and permeation tests. It was found that the prepared membrane was stable; especially the TiO2 layer of the membrane was found to be stable after several times of use for permeation test. The membrane showed a typical NF property, despite of the presence of the TiO2 layer. From long time tests with or without UV light, it was found that there was good antifouling effect on the membrane by the TiO2 layer. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 相似文献
15.
研究了膜生物反应器的运行效果、膜污染特征。结果表明:膜生物反应器具有良好的污染物去除效果,在处理生活污水时COD的去除草达到90%以上,出水COD控制在80mg·L^-1以下,NH4-N的去除效果能达到95%,出水NH4-N浓度10mg·L^-1以下,膜污染的过程呈现明显的“两段式”特点,即过膜压力缓慢上升阶段和快速上升阶段。采用NaOH+NaClO联合清洗后,膜的过膜压力迅速下降,表明膜污染以有机污染为主。 相似文献
16.
采用阻力系列模型分析了膜污染主要来自凹土在膜表面的沉积,通过Darcy定律过滤模型计算,确定过滤过程的阻力主要来自滤饼层阻力Rg,约占总阻力的85%。实验结果表明,单一的物理、化学清洗方法不能达到理想的清洗效果,采用化学方法和反冲技术相结合的清洗方法,可使膜的纯水通量恢复至新膜的89 %以上,且多次的清洗效果稳定。考察了反冲压力、反冲时间和反冲周期等因素对陶瓷膜微滤凹土浆液强化过程的影响,确定合适的反冲操作条件:反冲压力0. 5 MPa、时间10 s、周期20 min。反冲技术在陶瓷膜微滤过程的膜污染控制和再生环节上起了重要作用,并具有广阔的应用前景。 相似文献
17.
18.
19.
20.
Srgio F Aquino Alan Y Hu Aurangzeb Akram David C Stuckey 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2006,81(12):1894-1904
Two submerged anaerobic membrane bioreactors (SAMBRs) with essentially 100% cell recycle (150 days retention time, SRT), one with powdered activated carbon addition (PAC 1.7 g L?1) and one without, were continuously fed a low‐strength feed (450 mg COD L?1) in order to investigate membrane fouling and to characterize the foulants. The SAMBR which did not receive PAC experienced more fouling, and the molecular weight (MW) distribution showed that there was a greater amount of high‐MW compounds in this reactor when compared with the reactor with PAC. Size exclusion chromatography showed that although extracellular polymeric substances (EPS) seemed to contribute to the soluble chemical oxygen demand (COD) inside the reactor, it was mainly rejected by the membrane. High‐MW protein and carbohydrate material originating mainly from cell lysis and EPS seemed to be the main organics that contributed to the internal fouling of the membrane. Copyright © 2006 Society of Chemical Industry 相似文献