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1.
• Ceramic membrane filtration showed high performance for surface water treatment. • PTC pre-coagulation could enhance ceramic membrane filtration performance. • Ceramic membrane fouling was investigated by four varied mathematical models. • PTC pre-coagulation was high-effective for ceramic membrane fouling control. Application of ceramic membrane (CM) with outstanding characteristics, such as high flux and chemical-resistance, is inevitably restricted by membrane fouling. Coagulation was an economical and effective technology for membrane fouling control. This study investigated the filtration performance of ceramic membrane enhanced by the emerging titanium-based coagulant (polytitanium chloride, PTC). Particular attention was paid to the simulation of ceramic membrane fouling using four widely used mathematical models. Results show that filtration of the PTC-coagulated effluent using flat-sheet ceramic membrane achieved the removal of organic matter up to 78.0%. Permeate flux of ceramic membrane filtration reached 600 L/(m 2·h), which was 10-fold higher than that observed with conventional polyaluminum chloride (PAC) case. For PTC, fouling of the ceramic membrane was attributed to the formation of cake layer, whereas for PAC, standard filtration/intermediate filtration (blocking of membrane pores) was also a key fouling mechanism. To sum up, cross-flow filtration with flat-sheet ceramic membranes could be significantly enhanced by titanium-based coagulation to produce both high-quality filtrate and high-permeation flux. 相似文献
2.
• 1,4-Dioxane was degraded via the photo-Fenton reactive membrane filtration. • Degradation efficiency and AQY were both enhanced in photocatalytic membrane. • There is a tradeoff between photocatalytic degradation and membrane permeation flux. • Degradation pathways of 1,4-Dioxane is revealed by DFT analysis. The present study evaluated a photo-Fenton reactive membrane that achieved enhanced 1,4-Dioxane removal performance. As a common organic solvent and stabilizer, 1,4-Dioxane is widely used in a variety of industrial products and poses negative environmental and health impacts. The membrane was prepared by covalently coating photocatalyst of goethite (α-FeOOH) on a ceramic porous membrane as we reported previously. The effects of UV irradiation, H 2O 2 and catalyst on the removal efficiency of 1,4-Dioxane in batch reactors were first evaluated for optimized reaction conditions, followed by a systematical investigation of 1,4-Dioxane removal in the photo-Fenton membrane filtration mode. Under optimized conditions, the 1,4-Dioxane removal rate reached up to 16% with combination of 2 mmol/L H 2O 2 and UV 365 irradiation (2000 µW/cm 2) when the feed water was filtered by the photo-Fenton reactive membrane at a hydraulic retention time of 6 min. The removal efficiency and apparent quantum yield (AQY) were both enhanced in the filtration compared to the batch mode of the same photo-Fenton reaction. Moreover, the proposed degradation pathways were analyzed by density functional theory (DFT) calculations, which provided a new insight into the degradation mechanisms of 1,4-Dioxane in photo-Fenton reactions on the functionalized ceramic membrane. 相似文献
3.
• Effects of metabolic uncoupler TCS on the performances of GDMBR were evaluated. • Sludge EPS reduced and transformed into dissolved SMP when TCS was added. • Appropriate TCS increased the permeability and reduced cake layer fouling. • High dosage aggravated fouling due to compact cake layer with low bio-activity. ![]() The gravity-driven membrane bioreactor (MBR)system is promising for decentralized sewage treatment because of its low energy consumption and maintenance requirements. However, the growing sludge not only increases membrane fouling, but also augments operational complexities (sludge discharge). We added the metabolic uncoupler 3,3′,4′,5-tetrachlorosalicylanilide (TCS) to the system to deal with the mentioned issues. Based on the results, TCS addition effectively decreased sludge ATP and sludge yield (reduced by 50%). Extracellular polymeric substances (EPS; proteins and polysaccharides) decreased with the addition of TCS and were transformed into dissolved soluble microbial products (SMPs) in the bulk solution, leading to the break of sludge flocs into small fragments. Permeability was increased by more than two times, reaching 60–70 L/m 2/h bar when 10–30 mg/L TCS were added, because of the reduced suspended sludge and the formation of a thin cake layer with low EPS levels. Resistance analyses confirmed that appropriate dosages of TCS primarily decreased the cake layer and hydraulically reversible resistances. Permeability decreased at high dosage (50 mg/L) due to the release of excess sludge fragments and SMP into the supernatant, with a thin but more compact fouling layer with low bioactivity developing on the membrane surface, causing higher cake layer and pore blocking resistances. Our study provides a fundamental understanding of how a metabolic uncoupler affects the sludge and bio-fouling layers at different dosages, with practical relevance for in situ sludge reduction and membrane fouling alleviation in MBR systems. 相似文献
4.
• Cu2O NPs/H2O2 Fenton process was intensified by membrane dispersion. • DMAc removal was enhanced to 98% for initial DMAc of 14000 mg/L. • Analyzed time-resolved degradation pathway of DMAc under ·OH attack. ![]() High-concentration industrial wastewater containing N, N-dimethylacetamide (DMAc) from polymeric membrane manufacturer was degraded in Cu 2O NPs/H 2O 2 Fenton process. In the membrane-assisted Fenton process DMAc removal rate was up to 98% with 120 min which was increased by 23% over the batch reactor. It was found that ·OH quench time was extended by 20 min and the maximum ·OH productivity was notably 88.7% higher at 40 min. The degradation reaction rate constant was enhanced by 2.2 times with membrane dispersion ( k = 0.0349 min −1). DMAc initial concentration ( C0) and H 2O 2 flux ( Jp) had major influence on mass transfer and kinetics, meanwhile, membrane pore size ( rp) and length ( Lm) also affected the reaction rate. The intensified radical yield, fast mass transfer and nanoparticles high activity all contributed to improve pollutant degradation efficiency. Time-resolved DMAc degradation pathway was analyzed as hydroxylation, demethylation and oxidation leading to the final products of CO 2, H 2O and NO 3− (rather than NH 3 from biodegradation). Continuous process was operated in the dual-membrane configuration with in situ reaction and separation. After five cycling tests, DMAc removal was all above 95% for the initial [DMAc] 0 = 14,000 mg/L in wastewater and stability of the catalyst and the membrane maintained well. 相似文献
5.
随着我国污泥产量连年递增,污泥处理处置市场热度骤升.与传统的污泥厌氧消化相比,厌氧膜生物反应器(AnMBRs)体现出很大的优势.本文着重于AnMBRs处理污泥时的主要操作参数固体停留时间(SRT)、水力停留时间(HRT)、有机负荷(OLR)和温度对其消化性能影响的相关研究,并对AnMBRs的主要膜污染控制方法进行了综述... 相似文献
6.
利用管式或卷式纳滤膜处理废弃母液，在固定工艺条件下，透过液通量与浓缩时间呈一定数学关系；当浓缩进行到最后，透过液中的COD浓度会突然提高，该突然下降时间应长连续浓缩时间，抗生素截留率的变化规律基本与COD的去除率相同，但数值不同。利用COD的变化规律基本可以确定抗生素的变化趋势。 相似文献
7.
• A fine fibre (40–60 nm diameter) interlayer (~1 µm thickness) was electrospun. • Fine fibre interlayer promoted formation of defect-free dense polyamide layer. • FO membrane with dual-layer substrate had less organic fouling potential. • High reverse salt flux accelerated organic fouling on FO membrane. Nanofibre-supported forward osmosis (FO) membranes have gained popularity owing to their low structural parameters and high water flux. However, the nanofibrous membranes are less stable in long-term use, and their fouling behaviours with foulants in both feed solution (FS) and draw solution (DS) is less studied. This study developed a nanofibrous thin-film composite (TFC) FO membrane by designing a tiered dual-layer nanofibrous substrate to enhance membrane stability during long-term usage and cleaning. Various characterisation methods were used to study the effect of the electrospun nanofibre interlayer and drying time, which is the interval after removing the M-phenylenediamine (MPD) solution and before reacting with trimesoyl chloride (TMC) solution, on the intrinsic separation FO performance. The separation performance of the dual-layer nanofibrous FO membranes was examined using model foulants (sodium alginate and bovine serum albumin) in both the FS and DS. The dual-layer nanofibrous substrate was superior to the single-layer nanofibrous substrate and showed a flux of 30.2 L/m 2/h (LMH) when using 1.5 mol/L NaCl against deionised (DI) water in the active layer facing draw solution (AL-DS) mode. In the fouling test, the water flux was effectively improved without sacrificing the water/solute selectivity under the condition that foulants existed in both the FS and DS. In addition, the dual-layer nanofibrous TFC FO membrane was more robust during the fouling test and cleaning. 相似文献
8.
● Fundamentals of membrane fouling are comprehensively reviewed. ● Contribution of thermodynamics on revealing membrane fouling mechanism is summarized. ● Quantitative approaches toward thermodynamic fouling mechanisms are deeply analyzed. ● Inspirations of thermodynamics for membrane fouling mitigation are briefly discussed. ● Research prospects on thermodynamics and membrane fouling are forecasted. Membrane technology is widely regarded as one of the most promising technologies for wastewater treatment and reclamation in the 21st century. However, membrane fouling significantly limits its applicability and productivity. In recent decades, research on the membrane fouling has been one of the hottest spots in the field of membrane technology. In particular, recent advances in thermodynamics have substantially widened people’s perspectives on the intrinsic mechanisms of membrane fouling. Formulation of fouling mitigation strategies and fabrication of anti-fouling membranes have both benefited substantially from those studies. In the present review, a summary of the recent results on the thermodynamic mechanisms associated with the critical adhesion and filtration processes during membrane fouling is provided. Firstly, the importance of thermodynamics in membrane fouling is comprehensively assessed. Secondly, the quantitative methods and general factors involved in thermodynamic fouling mechanisms are critically reviewed. Based on the aforementioned information, a brief discussion is presented on the potential applications of thermodynamic fouling mechanisms for membrane fouling control. Finally, prospects for further research on thermodynamic mechanisms underlying membrane fouling are presented. Overall, the present review offers comprehensive and in-depth information on the thermodynamic mechanisms associated with complex fouling behaviors, which will further facilitate research and development in membrane technology. 相似文献
9.
本文就微絮凝过滤用于污水深度处理进行了研究.该工艺选用了陶粒一砂双层滤料滤池,絮凝剂选用了无机高分子絮凝剂PFC(投量20mg/L)和有机高分子絮凝剂(投量0.2mg/L);滤池的反冲洗用气一水·气一水三阶段反洗,效果良好.过滤实验的研究进行了直接过滤,单投PFC及PFC与PDM复配投加的微絮凝过滤三种方式.PFC与PDM复配对色度、COD、T—P有显著的去除效果. 相似文献
10.
在厌氧膜生物反应器处理高浓度食品废水的试验中,借助原子力显微镜分析了四种表面形貌不同的聚醚砜超滤膜的通量衰减规律.结果表明,超滤膜表面形貌愈粗糙,膜通量的衰减速率愈快,且化学清洗后恢复愈困难. 相似文献
11.
近年来,计算毒理学的方法被广泛应用于潜在的环境内分泌干扰物（EDCs）的筛选．膜雌激素受体（GPER）,作为一种可以快速响应内源性配体雌激素的关键靶蛋白,调控其介导的多项生理学功能．但是针对GPER的化合物毒性预测模型仍未见报道．因此,本研究收集了130个化合物对GPER的结合活性数据,主要包括双酚类、多溴联苯类以及农药杀虫剂类环境污染物．利用随机森林（RF）、支持向量机（SVM）、人工神经网络（ANN）、K最近邻（KNN）、朴素贝叶斯（NB）以及逻辑回归（LG）等6种机器学习算法构建二分类模型．结果显示,所有被测试算法的测试集准确率均达到85%以上,其中SVM、RF、ANN、KNN等4种算法的训练集准确率高于93%,10折交叉验证准确率高于80%,说明得到的模型具有优秀的分类预测性能．因此,本研究基于机器学习算法构建的分类模型,可以用来快速、准确地预测环境污染物是否通过结合GPER产生内分泌干扰效应．为评估环境污染物的潜在健康风险提供了理论依据． 相似文献
12.
膜生物反应器是一种新兴的水处理技术,但目前膜造价较高,导致运行费用较高,因此,提高膜通量的各种技术措施具有重要的意义。文中引入静态泥水混合液过滤试验,通过对取自运转中ＭＢＲ的活性污泥混合液的过滤实验结果分析,着重阐述了影响活性污泥可过滤性的影响因素,并指出在维持ＭＢＲ的运行中,改善活性污泥性状是一个不可忽略的方面。 相似文献
13.
在大量试验研究的基础上提出了一种改进型膜生物反应器 (MBR) ,并对其处理洗浴污水的效果进行了试验 ,结果表明 :利用改进型MBR处理洗浴污水出水水质良好 ,COD <40mg/L ,LAS <0 .2mg/L ,符合国家建设部颁布的生活杂用水回用水质标准。 相似文献
14.
集合了高斯烟流模式和烟团模式的优点,提出一个新的模型———轨迹烟流模式,既保留了烟流模式计算简单,计算结果连续的特点,又可以根据当时风场,确定不同的烟流轨迹,模拟烟团的弯曲、折回和重叠运动,分段进行计算,提高了计算的准确性扩大了模式应用范围。 相似文献
15.
用一体浸没式膜生物反应器(SMBR)不同特性膜处理上海市城市内河道水,结果表明,SMBR对氨氮含量较高的富营养化河水,氨氮的去除率在90%以上,但对COD的平均去除率仅为50%.比较两种膜的运行性能,亲水性膜在运行通量和通量恢复能力上,均比疏水性膜优越.两种膜的出水水质几乎没有差异. 相似文献
16.
试验采用在线空气反冲洗和在线清水反冲洗控制膜生物反应器(MBR)膜污染。试验结果表明,通过在线空气反冲洗,膜通量最大可恢复至20.5L/(m2·h),恢复率为95.3%,反冲洗周期为5d,且30d后膜通量仍大于12L/(m2·h);采用在线清水反冲洗后,膜通量最大可恢复至20.9L/(m2·h),恢复率为97.7%,第34天进行第3次在线清水反冲洗后膜通量仍可恢复至19.8L/(m2·h)。 相似文献
17.
本文对ＮＰ型复合纳滤膜的分离性能进行了初步实验并在此基础上采用纳滤膜平板过滤装置对豆腐加工过程中产生的废水进行处理,以降低废水中的ＣＯＤ含量,实验结果表明,ＮＰ型复合纳滤膜对０．２％ＭｇＳＯ４溶液的截留率（Ｒ）高于９０％,相应秀量约为２０Ｌｍ＾－２．ｈ＾－１（０．４ＭＰａ）,豆腐废水ＣＯＤ的去除率大于９０％ 相似文献
18.
提出非点源污染较全面、准确的概念，总结归纳出非点源污染9个方面的来源，综述了国内非点源污染模型及其控制管理的研究情况，并针对目前国内非点源污染模型研究及其控制管理研究存在的问题，指出未来该领域研究的重点和方向。文章认为，在模型方面，应把微观机理模型推广到宏观尺度，与大型流域管理模型相结合，而污染物风险分析功能模型、地理信息系统支持下的专家系统软件等是研究重点；在控制管理方面，污染物排放总量控制规划、人工模拟与野外实验相结合、应用经济手段等是研究的发展方向。 相似文献
19.
在一体式MBR系统中投加少量的粉末活性炭,运行效果良好,并且可以很好地降低膜污染。粉末活性炭在形成生物活性炭后,对难降解有机物具有很好的降解能力;NH4^ -N的去除率得到进一步提高,NO3^-的含量升高;但反硝化作用不明显,致使总氮去除率不高;生物活性炭很好地吸附并降解了易引起膜污染的有机物,改变了污泥的性质,对膜组件起到了很好的保护作用。 相似文献
20.
A novel nanocomposite OMWCNT-A-GO was synthesized by conjugating OMWCNT and GO. The P-OMWCNT-A-GO membrane was fabricated by non-solvent induced phase inversion. The P-OMWCNT-A-GO exhibits the best water flux, BSA rejection and flux recovery. It should be due to the enhanced membrane pore size, porosity and hydrophilicity. ![]() Although carbon nanomaterials have been widely used as effective nanofillers for fabrication of mixed matrix membranes (MMMs) with outstanding performances, the reproducibility of the fabricated MMMs is still hindered by the non-homogenous dispersion of these carbon nanofillers in membrane substrate. Herein, we report an effective way to improve the compatibility of carbon-based nanomaterials with membrane matrixes. By chemically conjugating the oxidized CNTs (o-CNTs) and GO using hexanediamine as cross-linker, a novel carbon nanohybrid material (G-CNTs) was synthesized, which inherited both the advanced properties of multi-walled carbon nanotubes (CNTs) and graphene oxide (GO). The G-CNTs incorporated polyvinylidene fluoride (PVDF) MMMs (G-CNTs/PVDF) were fabricated via a non-solvent induced phase separation (NIPS) method. The filtration and antifouling performances of G-CNTs/PVDF were evaluated using distillate water and a 1 g/L bovine serum albumin (BSA) aqueous solution under 0.10 MPa. Compared to the MMMs prepared with o-CNTs, GO, the physical mixture of o-CNTs and GO and pure PVDF membrane, the G-CNTs/PVDF membrane exhibited the highest water flux up to 220 L/m 2/h and a flux recovery ratio as high as 90%, as well as the best BSA rejection rate. The excellent performances should be attributed to the increased membrane pore size, porosity and hydrophilicity of the resulted membrane. The successful synthesis of the novel nanohybrid G-CNTs provides a new type of nanofillers for MMMs fabrication. 相似文献
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