Dissertations / Theses: 'Microfiltration'

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Till, Steven W. "Crossflow microfiltration of sewage effluents." Thesis, Cranfield University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267216.

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Silva, Claudio Mudado. "Flux prediction in high-shear microfiltration." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0010/NQ59095.pdf.

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Bromley, Alan J. "Slotted and circular pore surface microfiltration." Thesis, Loughborough University, 2002. https://dspace.lboro.ac.uk/2134/13634.

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The work described by this thesis is a comparison of pore opening geometry for true surface microfilters. True surface microfilters can be thought of as very fine sieves, with pore sizes less than 10 microns. All other types of so-called microfiltration membranes do not rely on sieving, but obtain their pore retention rating by particle collection mechanisms similar to depth filters. Particle deposition within such microfilters results in permeate flow rate dechne, for a fixed pressure filtration, or pressure drop rise, for a fixed rate filtration. The true surface microfilter pore geometnes considered were circular and slotted, and microfilters with filtering dimension of less than 10 microns were used. The slotted pore microfilters are not commercially available and had to be made in the laboratory as part of this study. The technique used was to plate nickel onto an existing substrate, thereby reducing the pore dimension until It was within the microfiltration range. The plating was by electroless nickel solution and not by galvanic means. Significant development of the electroless platmg technique led ultimately to the successful manufacture of process scale slotted surface microfilters.

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Tarleton, E. S. "A study of electrically assisted microfiltration." Thesis, University of Exeter, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374950.

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Rjimati, El Arbi. "Microfiltration tangentielle de suspensions particulaires : modélisation." Montpellier 2, 1990. http://www.theses.fr/1990MON20029.

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La caracterisation physique, par microscopie electronique, des membranes minerales microporeuses permet de calculer une permeabilite theorique du milieu filtrant et de mettre en evidence, le cas echeant, une structure composite. La comparaison des valeurs theoriques aux valeurs experimentales, mesurees par permeametrie a l'eau, permet de quantifier cet effet composite ainsi que les interactions possibles entre le permeat et la surface membranaire. La filtration d'une suspension de microparticules de bentonite provoque la mise en place quasi-instantanee d'un depot particulaire tres fin mais homogene sur la surface membranaire. Ce depot joue le role de membrane dynamique, sa resistance a l'ecoulement est preponderante devant celle de la membrane originale. Si la valeur de cette resistance depend peu de la permeabilite de la membrane choisie ou des conditions de circulation du retentat, elle est une fonction croissante de la pression operatoire choisie et de la concentration particulaire de la suspension a filtrer. Une representation parametrique de la variation de la resistance du depot en fonction des parametres operatoires testes est proposee. Enfin, si dans les conditions testees, l'application d'un champ electrique a peu d'effet sur les flux de permeat obtenus, une circulation de grosses particules (promoteurs de turbulence) dans le retentat permet une intensification importante du processus, le flux de filtrat obtenu est multiplie par un facteur 6

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Xu-Jiang, Yazhen. "Contribution a l'étude de la microfiltration." Vandoeuvre-les-Nancy, INPL, 1994. http://www.theses.fr/1994INPL050N.

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Ce mémoire est une contribution à l'étude de la microfiltration et de son application à la clarification de la bière. Il porte sur les deux techniques de microfiltration sur la membrane, frontale et tangentielle. Une première partie bibliographique fait un bilan des connaissances sur ces techniques dans le cas général et pour l'application bière. La deuxième partie, expérimentale, précise les paramètres importants (vitesse tangentielle, pression transmembranaire, mode de démarrage, nature de la membrane et de la bière) et leur incidence sur deux caractéristiques fondamentales de la filtration (flux et turbidité). Elle met aussi l'accent sur la réduction protéique en filtration tangentielle. La troisième partie concerne l'étude des phénomènes à l'interface suspension-membrane. La méthode expérimentale met en œuvre une technique originale de double filtration frontale appliquée d'abord au colmatage de membranes par la solution d'albumine de sérum bovin (BSA), puis transposée à la bière. Elle se termine par l'étude en filtration frontale et tangentielle du dépôt, dont on évalue la résistance spécifique, la compressibilité et la granulométrie. La quatrième partie propose trois axes de développement théorique. Le premier concerne l'évolution des modèles de filtration frontale au cours du temps. Le deuxième est une évaluation théorique des performances d'un lavage périodique à contre-courant applicable en filtration frontale et transposable dans ses conclusions à la filtration tangentielle. Le troisième est une analyse théorique de la microfiltration tangentielle prenant en compte la non-uniformité de l'écoulement et la formation d'un dépôt dans le canal amont

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Rabergeau, Gilles. "Concentration de suspensions bactériennes par microfiltration." Grenoble INPG, 1988. http://www.theses.fr/1988INPG0100.

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Rabergeau, Gilles. "Concentration de suspensions bactériennes par microfiltration." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37617785d.

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9

Marchant, Justin Quinton. "The crossflow microfiltration of concentrated titania dispersions." Thesis, Loughborough University, 1999. https://dspace.lboro.ac.uk/2134/27411.

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This work is the subject of an EPSRC-Tioxide Industrial CASE Award, the principal area of study being factors affecting the achievable steady state permeate flux during the crossflow microfiltration of concentrated titania dispersions. The performance of this continuous thickening process is of particular interest to Tioxide as a potential alternative to current batch filtration processes, which delay the manufacturing process.

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Henderson, J. S. "Combined microfiltration and membrane-based affinity separation." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325959.

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Ismail, Baharum. "Crossflow microfiltration of concentrated non-Newtonian slurries." Thesis, Loughborough University, 1996. https://dspace.lboro.ac.uk/2134/11787.

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Crossflow filtration of non-Newtonian slurries of magnesia and talc suspensions on micron-size membranes has been investigated. Three major membranes PTFE capillary, metal and ceramic tubes were employed and challenged by concentrated slurries more than 25 % by weight. Crossflow velocity, system pressure and slurry concentration are considered in relation to the possible deposit thickness and permeate flux behaviour. A thorough investigation of pressure drop in tubes of similar dimensions to the membranes has also been carried out in order to identify and develop an appropriate model. The experimental results, especially the deposit depth and flux rate are compared with the model prediction which is based on a permeate flux rate with shear stress correlation. Furthermore, diafiltration experiments were carried out and washing efficiency is compared with a stirred tank model of the process. Measurement of pressure drop in tubes confirmed the mathematical model used to determine the diameter open to flow during filtration, i.e. the deposit thickness. Overall crossflow experimental results show reasonable agreement with the predictions of the proposed models. The pseudo steady state flux is shown to correlate with the wall shear stress and the correlation is much improved when the deposit depth on the membrane was taken into account. In most cases the deposit depth and permeate flux rate are correctly predicted once the basic parameters correlation data and slurry rheology were determined. Since the rheology properties can be determined independently, the mathematical model developed is very practical and could be extended to some other systems, for example tube diameter. Hopefully, the translation of these parameters could be used to design and then develop the appropriate equipment when crossflow filtration of concentrated slurries is concerned, and in the design of systems to prevent tube blockage.

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Xiao, Yuan, Yi Lu, Michael Hsieh, Joseph Liao, and Pak Kin Wong. "A Microfiltration Device for Urogenital Schistosomiasis Diagnostics." Public Library of Science, 2016. http://hdl.handle.net/10150/614655.

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Schistosomiasis is a parasitic disease affecting over 200 million people worldwide. This study reports the design and development of a microfiltration device for isolating schistosome eggs in urine for rapid diagnostics of urogenital schistosomiasis. The design of the device comprises a linear array of microfluidic traps to immobilize and separate schistosome eggs. Sequential loading of individual eggs is achieved autonomously by flow resistance, which facilitates observation and enumeration of samples with low-abundance targets. Computational fluid dynamics modeling and experimental characterization are performed to optimize the trapping performance. By optimizing the capture strategy, the trapping efficiency could be achieved at 100% with 300 mu l/min and 83% with 3000 mu l/min, and the filtration procedure could be finished within 10 min. The trapped eggs can be either recovered for downstream analysis or preserved in situ for whole-mount staining. On-chip phenotyping using confocal laser fluorescence microscopy identifies the microstructure of the trapped schistosome eggs. The device provides a novel microfluidic approach for trapping, counting and on-chip fluorescence characterization of urinal Schistosoma haematobium eggs for clinical and investigative application.

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Valentine, Mark Edward. "Fundamental flux enhancement modelling of membrane microfiltration." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:f1b0388e-25b9-4038-be04-360b1414d172.

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Membrane filtration is used in a variety of industries, including water treatment and the food industry. Membrane systems include microfiltration and reverse osmosis processes. Membranes used in reverse osmosis are nonporous or pores at 0.2-2 A. This work will focus on mechanical microfiltration. These filtration systems suffer from an accumulation of the rejected material near the membrane surface. This causes additional resistance to the flow through the membrane (flux), resulting in a decline in the performance of the system. Sparging gas bubbles into the mixture has been shown to improve performance. The flow field promotes the transport of material away from the membrane surface and into the bulk. The goal is to predict the sparging that will achieve the maximum flux. Existing flux prediction models often assume steady shear at the membrane surface but in bubbling regimes the shear stresses are unsteady. In this thesis a model is developed to calculate the flux based not solely on shear but on the behaviour and resistance of suspended particles in a gas-liquid flow field. The bubble shape and flow field is calculated using computation fluid dynamics (CFD). The flow around a bubble in gap between two parallel flat sheet membranes is investigated. The calculated bubble shape correlates well with the results seen in experiments. The bubble rise velocity with respect to gap width is shown to transition between that expected in the literature for extended flow for large gap widths and that for a two dimensional case for smaller gap widths. The transitional region however, does not behave as may be expected. The rise velocity does not monotonically decrease as the gap width is reduced. The particle concentration is found by the solution of the convection-diffusion equation, where the convection velocity terms are given by the results of the CFD calculation. The permeate flux is then calculated using a resistance model giving the enhancement due to the bubble. The model is also applied to single phase crossflow. As the shear stresses are steady in this single-phase flow regime, established membrane shear linked mass-transfer coefficient methods can be employed. Good agreement is found between the model and theory. The flux results obtained when the model is applied to the flow around the bubble show a peak in performance with respect to the gap between the membranes for a given bubble volume. The optimal flux enhancement is found to correlate well with the bubble size compared to the flow area. The results show a bubble width of around 60% of the flow width provides the best flux performance.

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Koh, Chen Ning. "Microfiltration and ultrafiltration with high frequency backpulsing /." Aachen : Shaker, 2009. http://d-nb.info/995622019/04.

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Heinemann, Petra Regina. "The problem of fouling in crossflow microfiltration." Thesis, University of Bath, 1987. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.377962.

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Chove, Bernard. "Emulsifying properties of soy protein isolates obtained by isoelectric and membrane fractionation." Thesis, University of Reading, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367716.

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Li, Hong-yu Graduate School of Biomedical Engineering Faculty of Engineering UNSW. "Mechanism studies for crossflow microfiltration with pulsatile flow." Awarded by:University of New South Wales. Graduate School of Biomedical Engineering, 1995. http://handle.unsw.edu.au/1959.4/17858.

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The mechanism of how pulsatile flow affects flux behaviour in crossflow micro-filtration was investigated. The effects of pulsatile flow were sub-divided into shear effects and backflushing effects. A servo-valve hydraulic piston pump was applied to generate pulsatile flows in the membrane module with particular waveforms. Four types of fluid pulsation with specific flow-rate and pressure waveforms were produced for experimental tests. Two parameters, /dVcf\dt/ maxand Pmin, were examined independently for their effect during pulsatile flow, which was estimated by comparing the cake resistance during steady flow and pulsatile flow at the same mean crossflow velocity, trans-membrane pressure and membrane resistance. Filtration tests for all the pulsatile flows with clean water confirmed that pulsatility only affects cake depositions. Without particles, no flux improvement was obtained. The results for the microfiltration of 0.5g/1 silica suspension showed that for pulsatile flows without backflushing (i.e. no negative transmembrane pressure peak), the fluid pulsation decreased cake resistance when the shear related parameter /dVcf\dt/max exceeded a critical value for each given waveform. When the instantaneous transmembrane pressure reached negative values, i.e. back-flushing occurred, the cake resistance was reduced for all pressure waves tested. Cake resistance was reduced more for more negative P min. With two of the waveforms tested, the cake resistance was almost completely eliminated. In contrast, the shear affected cake resistance reduction differently for each waveform. Comparing cake reduction results for different pulsatile waveforms, it was found that, for the square wave, the cake resistance reduction was higher for both shear and backflushing effect tests, while for the short spike waveform, the cake resistance reduction was lower. The flux waveforms were seen to follow the variations in transmembrane pressure. The flux response time was longer than the time required for the pressure changes, but was not dependent on the direction of the pressure change.

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Porcelli, Nicandro. "Chemical cleaning of potable microfiltration and ultrafiltration membranes." Thesis, Cranfield University, 2009. http://dspace.lib.cranfield.ac.uk/handle/1826/4659.

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Concerns over possible waterborne disease forced drinking water supply companies in England and Wales to adopt microfiltration and ultrafiltration technologies rapidly. MF and UF membrane plants are designed to produce water of a consistent quality regardless of throughput and fluctuations in the feedwater quality. To operate well they need to maintain flux and balance the rate of fouling, and chemical cleaning performance is critical to this. Giant steps have been taken into characterizing the foulants scientifically in the last few years while cleaning is reactive and ad hoc. This thesis explores the basis for a corresponding cleaning science for the technology to develop quantitively. Cleaning performance was defined in terms of a response to combinations of explanatory variables in a materials limited cleaning envelope. The study focused on applying variations of cleanant concentration, applied temperature and soak times to a variety of membranes fouled with different waters and regimes. An experimental design was developed and applied consistently to a number of different sampled sites; allowing an optimised recovery from the polynomial expressions for each treatment, through factorial analysis of the data. The size and variety of the data set analysed allowed comparison and quantification of the different deviations from optimal cleaning response. This effect was seen to vary temporally and with operating regime and the methods usefulness as a practical tool in the membrane plant lifecycle was considered. Cost evaluation of the variation in cleaning response showed that sub-optimal cleaning costs and energy use may be significant and the thesis also illustrated how module geometry affects initial cake deposition and thus cleanability. By demonstrating the potential for cleaning factor analysis, the potential for a combined heuristic and predictive cleaning control science is possible, but will need new strategies to manage technology change.

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Alanezi, Yousef H. "Crossflow microfiltration of oil from synthetic produced water." Thesis, Loughborough University, 2009. https://dspace.lboro.ac.uk/2134/8815.

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Produced water is formed in underground formations and brought up to the surface along with crude oil during production. It is by far the largest volume byproduct or waste stream. The most popular preference to deal with produced water is to re-inject it back into the formation. Produced water re-injection (PWRI) needs a treatment before injection to prevent formation blockage. Due to the increase of produced water during oil production in the west of Kuwait, an effluent treatment and water injection plants were established and commissioned in 2004 so that produced water could be used for re-injection purposes. It is estimated that oil wells in the west of Kuwait produce 15 to 40 % of produced water. The main aim of this treatment train is to reduce not only the oil-in-water amount to less than 10 ppm, but also total suspended solids to 5 ppm which is the maximum allowable concentration for re-injection and disposal. Furthermore, with respect to the upper limit for injection, the maximum number of particles between 5 and 8 microns is 200 in 0.1 ml. In practice the number is found to exceed this limit by 10 times...

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Morin, Pierre. "On the fractionation of buttermilk by microfiltration membranes." Thesis, Université Laval, 2006. http://www.theses.ulaval.ca/2006/23852/23852.pdf.

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Hu, Binjie. "Cross flow microfiltration of water in oil emulsion." Thesis, University of Newcastle Upon Tyne, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366591.

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Li, Weiyi. "Fouling Models for Optimizing Asymmetry of Microfiltration Membranes." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1258479637.

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Awang, Abdul Rahman bin. "Seeded microfiltration of copper with modified activated carbon." Thesis, Loughborough University, 2001. https://dspace.lboro.ac.uk/2134/35238.

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In this study the use of seeded microfiltration (MF) with modified powdered carbon focussed on the removal of copper ions from an aqueous solution. The aim of the study was to look into the possibility of utilisation of suitable modified activated carbons combined with membrane filtration (microfiltration) as an alternative technique for the treatment and recovery of copper ions from liquid wastes, to give high removal efficiency with low energy consumption. To enhance the filtration process, the particle size of modified activated carbon used was small because it provides a larger surface area and a shorter diffusional distance for base metals to be adsorbed. Furthermore, in order to minimise the fouling effect, a surface filter (nickel membrane) which had pores, or slots, that passed directly from one side of the filter to the other with no tortuosity was used.

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Boahen, Anthony Kwaku. "Purification of oily water with cross flow microfiltration." Thesis, University of Bath, 1999. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311233.

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Hughes, David James. "Novel tools for the analysis of fouling in microfiltration." Thesis, University of Oxford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.442839.

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Smail, Bentaïba. "Microfiltration tangentielle et lavage de suspensions de latex industriels." Vandoeuvre-les-Nancy, INPL, 1990. http://www.theses.fr/1990INPL078N.

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Le travail présenté dans ce mémoire concerne une étude expérimentale de la microfiltration tangentielle de suspensions de Latex industriels de polyacétate de vinyle, et son application à la diafiltration qui est une technique de lavage des suspensions. La première partie présente une étude de l'influence de l'eau de préparation de suspension (eau pure + dodécylsulfate de sodium + azide de sodium) sur l'état de la membrane. On montre que le SLS, présente dans l'eau, provoque une nette diminution du flux de perméat. En conséquence les expériences ultérieures ont été réalisées avec des suspensions préparées uniquement avec de l'eau pure, auxquelles on additionne de petites quantités d'antibactérien (l'acide de sodium). Ensuite on détermine les perméabilités initiale et finale de la membrane pour voir s'il est possible de garder la même performance initiale de la membrane en pratiquant des lavages de longue durée. Par ailleurs on étudie la performance de la microfiltration tangentielle avec et sans rinçage pour montrer l'efficacité des rinçages périodiques et de courtes durées et l'intérêt de cette procédure lorsqu'il s'agit de traiter des suspensions très peu chargées. Finalement, on détermine l'influence des paramètres de fonctionnement et de la nature de la membrane sur le flux stationnaire de perméat. La deuxième partie de ce travail est consacrée au lavage des suspensions, en particulier la diafiltration continue et discontinue. Une étude théorique de ce dernier mode, sous forme de suite de cycles dilution-concentration, est confrontée aux résultats expérimentaux. Dans une étude théorique de la diafiltration en continu on montre l'influence de deux paramètres ; nombre d'étages et nombre de diavolumes sur l'efficacité de l'opération

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N'Guiambo, Roger. "Microfiltration transversale des suspensions colloïdales avec adjuvants de filtration." Vandoeuvre-les-Nancy, INPL, 1988. http://www.theses.fr/1988NAN10197.

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La caractérisation de la texture des recouches d'adjuvant est faite par la méthode des pressions capillaires qui permet la détermination de la distribution de taille de pore ainsi qu'une estimation de la porosité des précouches. Les mesures de perméabilité sous champ gravitaire laissent apparaitre des différences notoires avec les perméabilités des modèles théoriques. Un dispositif expérimental est mis en place pour l'étude des mécanismes de dépôts, de l'efficacité de capture et de relargage des particules ainsi que l'évolution des pertes de charge en fonction du temps. Un modèle de filtration avec adjuvants est proposé

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MENARD, GEORGES. "Contribution a l'etude de la microfiltration tangentielle des gaz." Chambéry, 1990. http://www.theses.fr/1990CHAMS001.

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Dans cette etude, nous experimentons la possibilite d'appliquer la microfiltration tangentielle aux gaz. L'interet de ce procede reside dans son aptitude a faciliter l'agglomeration de l'aerosol initial et a limiter l'epaisseur du depot. De ce fait la pression differentielle de filtration reste pratiquement constante au cours du temps. L'element filtrant de notre installation experimentale presente une geometrie tubulaire. Le gaz charge en aerosols circule a l'interieur du tube. Seule une fraction du debit principal est filtree par passage a travers la paroi poteuse. Le coefficient de partage est defini, comme le rapport du debit massique filtre sur celui a l'entree du module de filtration. Pour un debit de filtration donne, lorsque le coefficient de partage est faible, nous montrons qu'au-dela d'une periode de fonctionnement, la pression differentielle ainsi que la masse du depot atteignent une limite. Grace a une analyse granulometrique des depots, nous montrons que plus le coefficient de partage diminue, plus le diametre median massique des particules le constituant, est faible. Enfin, pour un depot construit dans des conditions definies, nous recherchons la vitesse limite de decolmatage en fonction de la vitesse de filtration. Pour une vitesse de filtration nulle, le decrochement du depot n'apparait que si la vitesse tangentielle atteint une valeur importante. La vitesse de decolmatage croit ensuite proportionnellement a la vitesse di filtration

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Knopp, Thomas Karl. "Lipoprotein removal from cheese whey by cross-flow microfiltration." Connect to resource, 1992. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1202145220.

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N'Guiambo, Roger. "Microfiltration transversale des suspensions colloïdales avec adjuvants de filtration." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37617010k.

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31

Martin, Eric Todd. "Performance of a Wastewater Treatment Pond System with Microfiltration." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/906.

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ABSTRACT PERFORMANCE OF A WASTEWATER TREATMENT POND SYSTEM WITH MICROFILTRATION Eric Martin The Woodlands Wastewater Treatment Plant (WWWTP) treats wastewater from the Woodlands housing community near Nipomo, California. The treated effluent is recycled for irrigation of a golf course within the community. The treatment facility consists of three facultative ponds in series followed by a microfiltration system and chlorine disinfection. Microfiltration of wastewater pond effluent is a fairly new, and potentially challenging, application of microfiltration. This thesis describes the operating conditions and behavior of the WWWTP pond system followed by a microfiltration system for the purpose of producing recyclable water fit for reuse under the regulations of Title 22. Water quality data were compiled in two ways. Weekly influent and effluent water quality and flow measurements conducted by the WWWTP operators over the course of three years were studied to show the treatment trends of the treatment plant as a whole. In addition, weekly water quality tests were performed on samples of wastewater influent, effluent, and intermediate stages of treatment for 20 weeks and studied to show treatment performance of each individual pond and the microfiltration system. Pond treatment performance was analyzed based on removal of biochemical oxygen demand (BOD) and total suspended solids (TSS) and accumulation of sludge within the pond system. Microfiltration performance was analyzed in terms of meeting the TSS discharge requirement and the membrane fouling rate. The power consumption of the pond system components and the microfiltration system were estimated. The data show that the WWWTP is producing very high quality discharge. Without microfiltration, five-day carbonaceous soluble BOD (csBOD5) averaged 3.0 mg/L and TSS averaged 42.5 mg/L. BOD5 and TSS removal efficiencies were greater than 90%. Microfilter effluent BOD5 and TSS concentrations averaged 3.0 mg/L and 1.6 mg/L, respectively. Total ammonia nitrogen was reduced to 1.61 mg/L. pH remained between 6.5 and 8.5 with few temporary exceptions. The sludge accumulation was at the high end of the range of typical accumulation rates. However, the measured rate is for the first three years of operation and so likely over-estimates the long-term accumulation rate. Although the treatment performance of the WWWTP is excellent, the power consumed was high.

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Wang, Li. "Internal surface coating and photochemical modification of polypropylene microfiltration membrane." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ30119.pdf.

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Connell, Heather Anne. "Effect of particle shape on the flux in crossflow microfiltration." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0007/MQ32476.pdf.

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Koh, Chen Ning [Verfasser]. "Microfiltration and Ultrafiltration with High Frequency Backpulsing / Chen Ning Koh." Aachen : Shaker, 2009. http://d-nb.info/1156518660/34.

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35

Al-Malack, Muhammad Hassan. "Applications of dynamic membranes to crossflow microfiltration of secondary effluent." Thesis, University of Newcastle Upon Tyne, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335944.

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Pongpairoj, Pharima. "Effect of shear patterns and EPS on fouling in microfiltration." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:f75311a0-7885-4df2-ba45-82f034aeea98.

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Concentration polarisation and fouling reduce performance as well as increase costs. In order to mitigate these effects, understanding the cause and effects of these phenomena is crucial. It has been hypothesized, and to a certain extent shown, that amelioration of fouling can be achieved through the use of time varying shear for example use of air-sparging or sharp changes in crossflow velocity. Nevertheless the effect of shear on membrane fouling, in particular its effect on the foulant deposition and the transmission of small molecules in microfiltration, is not well understood. The goal of this project was to achieve an understanding of various foulant be- haviour. The work was divided into two parts. Firstly, the observations of fouling by freshwater algae, Chlorella Sorokiniana, were carried out at Nanyang Technolo- gical University, Singapore. Observations using macroscopic parameters were ex- amined with an optical non-invasive observation technique called Direct Observa- tion Through Membrane (DOTM). The result yielded a novel relationship between operating flux, crossflow velocity and transmission of extracellular polysaccharide. Interestingly shear was shown to have positive as well as negative effects on fouling of microfiltration membrane. The analysis of permeate has clearly shown that a maximisation of shear rate was not ideal. The second part was concerned with observations of the effect of shear patterns on membrane fouling using newly fabricated special membrane filtration cell, Direct Shear Stress Test Cell (DSSTC), designed to fit an Anton Paar rheometer and op- erate at constant flux. Unlike the-constant-shear-filtration cells, one could impose a very wide variety of shear regimes including intermittent sharp changes of direction and sinusoidal oscillations in the DSSTC. The effect of shear patterns on transmis- sion and fouling of a model polysaccharide (Dextran Blue) through microfiltration membranes was carried out at various conditions. Again, the results showed that the maximisation of shear rate was not ideal. The effect of shear patterns and EPS on fouling by yeast suspension was also studied using the DSSTC. The benefit of oscillatory shear is foulant dependent. For example, square wave oscillatory shear led to lower relative fouling for yeast EPS, but it resulted in higher relative fouling for unwashed yeast.

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Gesan-Guiziou, Geneviève. "Microfiltration tangentielle de lactoserum doux pretraite : mecanismes et conduite operatoire." Rennes 1, 1993. http://www.theses.fr/1993REN10112.

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La microfiltration tangentielle, qui permet de retirer la matiere grasse residuelle du lactoserum doux pretraite, est une etape necessaire a la production de concentres de proteines de haute purete. Cependant, les performances de ce procede (permeabilite et selectivite) sont limitees par des phenomenes de colmatage. De maniere a preciser les phenomenes qui regissent cette microfiltration, une analyse statistique des performances d'une installation industrielle a ete effectuee. Cette etude a montre le role joue par le pretraitement du lactoserum, l'etat initial de la membrane et le chemin operatoire pour atteindre les conditions stationnaires. Chacun de ces points ainsi que les parametres operatoires definissant la conduite de la microfiltration ont ete approfondis au laboratoire avec une plate-forme equipee d'un nouveau concept hydraulique: la recirculation du permeat a co-courant du retentat. Ce systeme permet une plus grande homogeneite des conditions de filtration le long de la membrane et peut ainsi ameliorer les performances de la microfiltration. Avec ce systeme, nous avons montre que la resistance initiale de la membrane et le pretraitement du produit doivent etre correctement maitrises afin d'eviter les variations des performances. La pression du compartiment retentat doit etre ajustee a une valeur minimale compatible avec les autres contraintes du procede. Enfin, une attention particuliere doit etre apportee au mecanisme competitif convection/erosion qui regit, a tout instant de la microfiltration (conditions transitoires et stationnaires) les caracteristiques qualitatives et quantitatives des couches colmatantes, definissant la permeabilite au solvant (flux) et aux solutes (transmission des proteines). Les resultats obtenus ont permis de suggerer des modes de conduites plus efficaces

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BHAYANI, RACHIT B. "COLOR REMOVAL OF DYES WASTEWATER BY COAGULATION AND MICROFILTRATION PROCESSES." Cleveland State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=csu1419353682.

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39

Pamula, Abhiram Siva Prasad. "Adsorption and microfiltration processes to treat dye and coffee wastewater." Cleveland State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=csu1529685125294975.

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Largueze, Christophe. "Raffinage des huiles végétales par microfiltration : interaction milieu hydrophobe/membrane." Montpellier 2, 1997. http://www.theses.fr/1997MON20062.

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Pouet, Marie-Florence. "Traitements physico-chimiques associés à une microfiltration d'eau usée urbaine." Montpellier 2, 1994. http://www.theses.fr/1994MON20040.

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L'utilisation de la microfiltration tangentielle en traitement des eaux usees devrait permettre de garantir la qualite des effluents indispensable dans certaines zones. L'emploi direct d'une microfiltration ne peut toutefois etre envisagee sans l'apparition rapide d'un colmatage du milieu filtrant. L'identification des particules colmatantes doit donc etre etablie pour mieux optimiser le procede. La premiere partie de ce travail est consacree a une caracterisation des eaux usees urbaines basee sur une classification granulometrique de la pollution. Trois classes de particules colmatantes organiques ont ete ainsi definies: la fraction decantable, la fraction supracolloidale et la fraction soluble. Dans la seconde partie, dans le but de reduire le pouvoir colmatant des eaux usees brutes, sont etudies et compares deux pretraitements: l'electrocoagulation - flottation et la coagulation - floculation - decantation lamellaire. Les resultats montrent une transformation des fractions soluble, colloidale et supracolloidale en particules decantables. Dans les conditions optimales de pretraitement, plus de 80% de la fraction supracolloidale et jusqu'a 40% de la fraction soluble sont eliminees. La derniere partie du travail concerne la microfiltration des eaux usees urbaines pretraitees. Le role de chacune des fractions est etudiee. Il apparait que le phenomene limitant les performances de la microfiltration d'eaux pretraitees est essentiellement lie aux fractions supracolloidale et soluble. Les flux de permeation obtenus sur membranes minerales de diametre de pores de 0,2 m peuvent alors atteindre des valeurs depassant 0,3 m#3m##2h##1. Des essais effectues sur des eaux secondaires d'origine differente montrent et confirment la complexite du colmatage: la nature meme des matieres organiques, plus que leur quantite aurait, en fait, un role determinant dans le colmatage des membranes

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Erdem, İlker Çiftçioğlu Muhsin. "Preparation of ultrafiltration/ microfiltration ceramic composite membranes for biotechnology applications/." [s.l.]: [s.n.], 2002. http://library.iyte.edu.tr/tezler/master/biyoteknoloji/T000299.pdf.

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43

Zhang, Guan Mei. "Crossflow microfiltration modelling and mechanical means to prevent membrane fouling." Thesis, Loughborough University, 1992. https://dspace.lboro.ac.uk/2134/25663.

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The definition, history and applications of Microfiltration (MP) are briefly reviewed in Chapter 1. The physical mechanisms and mathematical models of the filtration process including concentration polarization (CP), gel polarization (GP) and pore blocking are given in Chapter 2. Crossflow microfiltration membrane fouling and the deposition of solids onto the filter surface have been investigated using a process fluid (seawater), latex and a ground mineral. The performance of various membrane materials has also been studied, including: acrylonitrile, polypropylene, PTFE, ceramic and stainless steel. The seawater filtration work showed in Chapter 3 that good filtrate flux rates can be maintained if material fouling or depositing on the membrane can be prevented from entering the membrane structure. A surface deposit may be removed by mechanical means such as backflushing with permeate or compressed air. This aspect of the work indicated that a more comprehensive study of fouling was required. Existing crossflow filtration membrane models did not adequately represent even the simplest filtration when penetration of the membrane structure applied. Such conditions occurred during latex filtration in Chapter 4. Latex of varying sizes and density were manufactured and filtrations using acrylonitrile membranes were performed. Considerable deposition of latex inside the membrane pores occurred despite the nominal rating of the membrane being less than the latex particle diameter. Thus the membranes relied on a depth filtration mechanism rather than a surface straining mechanism for filtration effectiveness. A standard filtration blocking model was modified for use in crossflow microfiltration, coupled with a mass balance on the amount of material filtered. This mathematical model was then used to predict and correlate the rate of filtration flux decay with respect to filtration time during crossflow filtration. The model provided acceptable accuracy and is an improvement on existing empirical models for the flux decay period. Under the circumstances of membrane penetration it is advisable to minimise the amount of material entering the membrane structure. Mechanical means to achieve this were investigated and a novel anti-fouling method using a centrifugal field force and enhanced shear stress at the membrane surface was developed. The filtration of limestone slurries with three different tubular filters are presented in Chapter 5, in which one filter was conventional, the other two novel ones were specially designed for the separation of particles with a density different from that of the liquid, one used a helical channel around the filter, and the other had tangential inlet and outlet endcaps. The centrifugal force produced by the spinning flow around these two filters retarded the approach of particles towards the membrane surface so that the particle deposition was reduced. The results showed such a system was energy efficient, saving 20 % of the energy required to effect a separation of mineral material compared with using the membrane in a more conventional way.

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Fitzgerald, Laura Emma. "The application of microfiltration as a partial sterilisation technique for the reduction of psychrotrophic spore forming bacteria from viscous dairy feeds." Thesis, University of Bath, 2012. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.582874.

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The use of microfiltration as an alternative to pasteurisation to reduce the microbial load of raw skimmed milk is a well established technology. However, its application in reducing bacteria from highly viscous dairy based solutions has not due to issues of low flux and high fouling tendency. This study involves the application of microfiltration to remove spores from high solids content Milk Protein Isolate (MPI) solutions. MPI feeds were inoculated with Bacillus mycoides spores a safer alternative to Bacillus cereus, a psychrotrophic spore forming bacteria found in dairy feeds. Suitable protocols for MPI resolubilisation, Bacillus mycoides cell and spore preparations were established and the membranes, MPI and spores were fully characterised by scanning electron microscopy (SEM), particle size distribution, rheology and pure water flux (PWF) measurements. Feed and permeate samples collected during experiments were analysed for solids content by oven drying, protein content using the Bradford assay and spore content using PetrifilmTM Aerobic count plates. To try and determine an optimum protocol for MPI filtration, a variety of filtration rig set-ups, modules and membranes were tested. Experiments were carried out at different MPI concentrations (4 – 16 wt%), cross flow velocities (CFV’s) (0.7 – 2.0 m s-1) and transmembrane pressures (TMP’s ) (1 and 2 bar). The filtration of 15 wt% MPI proved challenging. The best set of results were obtained using the 12.0 μm membrane at 1.4 m s-1, producing a 27 LMH flux, 96.5% protein transmission and a 2.1 log spore reduction. These results indicate that large pore ceramic microfiltration may be a suitable technology to replace or augment pasteurisation for high solids content dairy feeds. The effect of backwashing using different durations and frequencies was investigated. Backwashing parameters of 10 seconds every 5 minutes at 1 bar were found to be the most effective. The optimum cleaning regime found for MPI fouled ceramic membranes involved a long rinsing backflush at 1 bar, acid and alkali steps without backwashing, which produced a 99.6% flux recovery.

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Harb, Ramzi. "Asymmetric metakaolin-based geopolymer membranes for microfiltration: synthesis and first characterizations." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.

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In this preliminary study, metakaolin-based geopolymer samples were synthesized. For the synthesis of support samples, casting and pressing shaping methods were considered. Moreover, the deposition of a layer by dipping was carried out. Support and selective layer samples produced by casting were made of an aqueous sodium silicate solution, sodium hydroxide, foaming and stabilizing agents, as well as metakaolin precursor, and supports obtained by pressing involved the addition of solid-state anhydrous sodium metasilicate and water to the metakaolin precursor. Both pressed and cast samples were cured at 70°C for 24h and then left at room temperature for 6 days. Initial characterization experiments were conducted on the support samples. Concerning pressed samples, increases in both pressure loads and water concentrations led to increases in their mechanical performance, and decreases in their hydraulic permeabilities and total open porosities. It was therefore concluded that increases in both pressure load and water content leads to a higher compaction of the sample prepared, resulting in lower open porosity and higher mechanical properties. The study of porosity and pore size distribution has revealed that the pressed support pressed sample with 12% of water content at 2 MPa has an open porosity of 40% and a modal pore size value of 23.45 µm and meets the typical porosity of a ceramic membrane support. Results concerning cast samples were less satisfying with respect to pressed samples.The addition of foaming agents resulted in a heterogeneous distribution of pores. The addition of stabilizing agent improved the formation of a more homogeneous pore size distribution. An increase in liquid/precursor ratio led to an increase of the total open porosity. Finally, the slurry prepared with a high liquid/precursor ratio (L/P > 100) proved to produce a selective layer with a thickness of about 100 μm and a relatively good adhesion.

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46

Taylor, Mark. "Investigations into the fouling by beer solids on crossflow microfiltration membranes." Thesis, University of Surrey, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273220.

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Beamguard, Miles B. "Mathematical model of arsenic adsorption in a modified zeolite / Microfiltration System." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001804.

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Fradin, Benoit. "Fouling of microfiltration membranes for the dewatering of waste inorganic slurries." Thesis, University of Bath, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311249.

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Postlethwaite, Johnathan. "Vibrating membrane filtration : microfiltration performance during the processing of biological feedstreems." Thesis, University College London (University of London), 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.407601.

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Asaadi, Manouchehr. "Fouling behaviour and radioactive retention properties of inorganic crossflow microfiltration membranes." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/47755.

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