Microfiltration

Grape production and viticulture have great traditions in Hungary. Nowadays wine-making is only profitable if the end-product is quality wine. Good-quality wine can be produced from must which has the proper high sugar content. If there is an unfavorable vintage, it is necessary to enrich the must, to increase its sugar content and to eliminate its other defects. Grape juice is not only a sweetener; it can be used for other purposes too because the juice of the grape is a pleasant, fashionable soft drink as well. However, the must storage can cause some difficulties, as fermentation starts easily. The aim of the investigations was to use osmotic distillation and membrane distillation after the microfiltration and reverse osmosis concentration [1] for water removal from grape juice in order to reach a high sugar content, to the extent that makes it possible to preserve the grape juice without cooling.

In this study the applicability of membrane distillation (MD) was investigated to produce black-currant juice concentrate. For the experiments enzyme treated, pre-filtered by microfiltration and pre-concentrated by reverse osmosis fruit juice was applied. The measurements were carried out in a hollow fibre membrane contactor. Two different temperature differences were investigated as driving force: 15 and 198C. The shape of the curves of the fluxes appeared very similar at both temperature differences, however in case of the higher driving force the observed flux was 80% higher than in case of the lower driving force. By the MD process the pre-treated initial juice with 228Brix total soluble solid (TSS) content was concentrated up to 58.28Brix.

The neural network model is used for obtaining an estimation of permeate flux and rejection over the entire range of process variables. This approach has been extended in this study and applied to the prediction of flux sustainability and membrane efficiency of ceramic tubular membranes. Experimental results involving the use of turbulence promoters and the empty membrane filtration have been obtained and are directly compared to the predicted values from the black box model. Flux sustainability and membrane efficiency are dependent on feed temperature, system pressure, feed concentration and crossflow velocity. Neural networks also offer the added advantage of being quite straightforward in its application. The possibility of using BPNN (back-propagation network) to accurately predict variable effects on flux sustainability is included. Turbulence promoters were used experimentally to significantly enhance membrane efficiency and flux sustainability during microfiltration of dilute bentonite suspensions. Artificial neural networks can predict very accurately real system behaviour with relative errors reaching at most 5%. In order to obtain the data set necessary to train the different networks, three concentrations, three system pressures, three feed temperatures and one feed flowrate were tested in several operating conditions.

The eects of the substrate conditions on the volumetric productivity of Lactobacillus helveticus at dierent cell densities up to 60 g l A1 in a continuous stirred-tank reactor with micro®ltration to retain the biomass were investigated. At low dilution rates, D, the steady-state volumetric productivity, r p , gradually increased to a maximum at D 1.2±1.5 h A1 , because of reduced product inhibition. At higher D values, r p unexpectedly decreased, although the substrate conditions further improved. The maxima of r p at dierent cell densities coincided with a critical speci®c substrate utilization rate beyond which the cell metabolism seems to be controlled through a catabolic modulator factor, and r p decreases.

The reduction of acidity of passion fruit juice was investigated by electrodialysis (ED) with bipolar membranes (BM) at the laboratory and pre-industrial scale. Four states of juice were tested: initial pulpy juice, juice clarified by tangential microfiltration, twice-concentrated clarified juice, centrifuged juice. The ED performances were compared in terms of deacidification rate, current efficiency, and energy consumption. The deacidification was carried out up to pH 4.5 with satisfactory results. ED performances were lower with the pulpy and concentrated juices because of fouling of the anion-exchange membrane, which increased voltage. The differences in acidity between the juices was reduced by the pre-industrial ED stack, which involved better hydrodynamics through high flow rates and low compartment thickness. Whatever the juices, physico-chemical analysis showed that colour changed only slightly.

Palladium-based nanoparticles immobilized in polymeric matrices were applied to the reductive dechlorination of 3,3′,4,4′-tetrachlorobiphenyl (PCB77) at room temperature. Two different dechlorination platforms were evaluated using (1) Pd nanoparticles within conductive polypyrrole films; or (2) immobilized Fe/Pd nanoparticles within polyvinylidene fluoride microfiltration membranes. For the first approach, the polypyrrole film was electrochemically formed in the presence of perchlorate ions that were incorporated into the film to counterbalance the positive charges of the polypyrrole chain. The film was then incubated in a solution containing tetrachloropalladate ions, which were exchanged with the perchlorate ions within the film. During this exchange, reduction of tetrachloropalladate by polypyrrole occurred, which led to the formation of palladium nanoparticles within the film. For the second approach, the membranesupported Fe/Pd nanoparticles were prepared in three steps: polymerization of acrylic acid in polyvinylidene fluoride microfiltration membrane pores was followed by ion exchange of Fe 2+ , and then chemical reduction of the ferrous ions bound to the carboxylate groups. The membranesupported iron nanoparticles were then soaked in a solution of tetrachloropalladate resulting in the deposition of Pd on the Fe surface. The nanoparticles prepared by both approaches were employed in the dechlorination of PCB77. The presence of hydrogen was required when the monometallic Pd nanoparticles were employed. The results indicate the removal of chlorine atoms from PCB77, which led to the formation of lower chlorinated intermediates and ultimately biphenyl. Toxicity associated with vascular dysfunction by PCB77 and biphenyl was compared using cultured endothelial cells. The data strongly suggest that the dechlorination system used in this study markedly reduced the proinflammatory activity of PCB77, a persistent organic pollutant.

The main problem in treating oil in water emulsions by membrane technologies is fouling caused by oil adsorption on the membrane surface. Among these technologies, microfiltration has been used in many fields of oil-water emulsions. The effect of operating conditions on a microfilter (home made) with a maximum pore size of 10 µm was investigated. The results show that by increasing temperature and pressure, the flux factor increases. Also, by increasing oil content, the membrane is fouled rapidly but not significantly and the flux factor decreases. Increasing volumetric flow rate causes an increasing flux factor. While most polymeric membranes are susceptible to fouling, this membrane is not.

This paper describes the manufacture of tubular UF and MF porous and supported ceramic membranes to oil/water emulsions demulsification. For such a purpose, a rigorous control was realized over the distribution and size of pores. Suspensions at 30 vol.% of solids (zirconia or alumina powder and sucrose) and 70 vol.% of liquids (isopropyl alcohol and PVB) were prepared in a jar mill varying the milling time of the sucrose particles, according to the pores size expected. The membranes were prepared by isostatic pressing method and structurally characterized by SEM, porosimetry by mercury intrusion and measurements of weight by immersion. The morphological characterization of the membranes identified the formation of porous zirconia and alumina membranes and supported membranes. The results of porosimetry analysis by mercury intrusion presented an average pore size of 1.8 mm for the microfiltration porous membranes and for the ultrafiltration supported membranes, pores with average size of 0.01-0.03 mm in the top-layer and 1.8 mm in the support. By means of the manufacture method applied, it was possible to produce ultra and microfiltration membranes with high potential to be applied to the separation of oil/water emulsions. #

There is a need for a low cost, sensitive, on-line sensor to assess the integrity of membrane modules used in the water industry for water treatment, membrane bioreactors and for pre-treatment prior to using nanofiltration or reverse osmosis. A sensor addressing this need is described whose operating principle is based on measuring the differential pressure across a membrane that intercepts a portion of the permeate from the pre-treatment module(s) relative to the differential pressure across a valve. The latter can be adjusted to maximize the sensitivity of the instrument. A dimensionless metric based on the differential pressures is defined and corroborated with the Silt Density Index. The sensitivity of this Integrity Sensor is demonstrated by its response to cutting one fiber in a UF pre-treatment module that contains 1500 hollow fibers.

Two a-alumina ceramic membranes (0.2 and 0.8 jam pore sizes) and a surface-modified polyacrylonitrile membrane (0.1 jam pore size) were tested with an oily water, containing various concentrations (250-1000 ppm) of heavy crude oil droplets of 1-10 ~tm diameter. Significant fouling and flux decline were observed. Typical final flux values (at the end of experiments with 2h of filtration) for membranes at 250ppm oil in the feed are ~30-40kg m-2 h-1. Increased oil concentrations in the feed decreased the final flux, whereas the crossflow rate, transmembrane pressure, and temperature appeared to have relatively little effect on the final flux. In all cases, the permeate was of very high quality, containing <6 ppm total hydrocarbons. The addition of suspended solids increased the final membrane flux by one order of magnitude. It is thought that the suspended solids adsorb the oil, break up the oil layer, and act as a dynamic or secondary membrane which reduces fouling of the underlying primary membrane. Resistance models were used to characterize the type of fouling that occurs. Both the 0.2 jam and the 0.8 jam ceramic membranes appeared to exhibit internal fouling followed by external fouling, whereas external fouling characterized the behavior of the 0.1 jam polymer membrane from the beginning of filtration. Examination of the external fouling layer showed a very thin hydrophobic oil layer adsorbed to the membrane surface. This oil layer made the membrane surface hydrophobic, as demonstrated by increased water-contact angles. The oil layer proved resistant to removal by hydrodynamic (shear) methods. By extracting the oil layer with tetrachloroethylene, followed by IR analysis, its average thickness at the end of a 2 h experiment under typical conditions was determined to be 60 ~tm for the 0.2 jam ceramic membrane and 30 jam for the 0.1 jam polymer membrane. These measured amounts of oil associated with the membrane at the end of the experiments are in good agreement with those determined from a simple mass balance, in which it is assumed that all of the oil associated with the permeate collected is retained on or in the membrane, indicating that the tangential flow did not sweep the rejected oil layer to the filter exit.

This work aims to develop a new mineral porous tubular membrane based on mineral coal fly ash. Finely ground mineral coal powder was calcinated at 700°C for about 3 h. The elaboration of the mesoporous layer was performed by the slip casting method using a suspension made of the mixture of fly ash powder, water and PVA. The obtained membrane was submitted to a thermal treatment which consists in drying at room temperature for 24 h then a sintering at 800°C. SEM photographs indicated that the membrane surface was homogeneous and did not present any macro defects (cracks, etc.). The average pore diameter of the active layer was 0.25 lm and the thickness was around 20 lm. The membrane permeability was 475 l/h m 2 bar.

Dimensional analysis of the mass, length and time shows that the steady state flux observed for microfiltration or ultrafiltration through inorganic composite membrane can be expressed using two dimensionless numbers. The shear stress number Ns compares the shear stress against the membrane wall to the driving pressure, while the resistance number Nf compares the convective cross-flow transport to the drived transport through a layer, whose resistance is the sum of all the resistances induced by the different processes which limit the mass transport. Experimental data obtained in ultrafiltration of hydrocarbon emulsions and microfiltration of methanogenic bacteria suspensions and secondary treated wastewater were recalculated in terms of these dimensionless groups. Straight lines were plotted whose slope depends solely on the suspension and the membrane and not on the solute concentration. A negative slope and a positive intersection with the Ns axis means that a cake layer or a polarization layer can be completely eliminated at a critical cross-flow velocity; this was the case for an inorganic particles suspension and for the methanogenic suspension. A straight line of negative slope followed by a plateau means that an irreversible fouling is superimposed to the reversible phenomenon; this was observed for a secondary treated wastewater. A positive slope means that fouling predominates; this was observed with hydrocarbon emulsions. ~ 1998 Elsevier Science B.V.

A theoretical model of dead-end microfiltration (MF) of dilute suspensions is proposed. The model is based on a sieve mechanism of MF and takes into account the probability of membrane pore blocking during MF of dilute colloidal suspensions. An integro-differential equation (IDE) that includes both the membrane pore size and the particle size distributions is deduced. According to the suggested model a similarity property is applicable, which allows one to predict the flux through the membrane as a function of time for any pressure, and dilute concentration, based on one experiment at a single pressure and concentration. The suggested model includes only one fitting parameter, β > 1, which takes into account the range of the hydrodynamic influence of a single pore. For a narrow pore size distribution in which one pore diameter predominates (track-etched membranes), the IDE is solved analytically and the derived equation is in good agreement with the measurements on different track-etched membranes. A simple approximate solution of the IDE is derived and that approximate solution, as well as the similarity principal of MF processes, is in good agreement with measurements using a commercial Teflon microfiltration membrane. The theory was further developed to take into account the presence of multiple pores (double, triple and so on pores) on a track-etched membrane surface.

Günümüzde Türkiye`de bölgesel içme ve kullanma suyu sıkıntısı yaşanmaktadır. Türkiye’de yağış miktarı bölgeden bölgeye farklılık göstermektedir.  Baraj, göl, akarsular gibi yüzeysel su kaynakları bulunmayan veya yetersiz olan bu bölgelerde, alternatif çözümlere yönelmek gerekmektedir.  Söz konusu alternatifler arasında en kalıcı ve ekonomik çözüm, mevcut kaynaklara yönelip, yüzey suyunu arıtarak içme ve kullanma suyu temin etmektir.

Her geçen gün üretimi ve kullanımı artan ters osmoz sistemlerin kapsamlı olarak yapılacak bir maliyet analizi, sistemlerin tasarım ve seçiminde ekonomik açıdan faydalı bilgiler sağlayacaktır. Dolayısıyla bu çalışmanın amacı, yüzey sularından ultrafiltrasyon ve ters osmoz membranları ile su temin edilmesi durumunda, membran sistemlerinin maliyet analizinin ve tasarımının yapılmasıdır.

Two polyvinylidene¯uoride micro®ltration membranes (GVHP and GVWP: Millipore, Bedford, MA) with a nominal pore size of 0.22 mm were challenged with mixed microbial cultures present in Milli-Q TM water and in secondary ef¯uent, and with a Gram-negative model bacterium, SW8, to investigate bacterial passage. Total bacterial counts measured microscopically using the DNA¯uorochrome DAPI revealed that the small bacteria in Milli-Q TM water passed MF membranes totally. The model bacterium, SW8 and bacteria from secondary ef¯uent were mostly retained with log reduction values (LRV) of 4 and 3.5, respectively. Transmembrane pressure did not in¯uence the levels of bacterial passage signi®cantly. Pore size effects were investigated with track-etched membranes (Poretics TM : Osmonics, Minnetonka MN) with nominal pore sizes of 0.2, 0.1 and 0.05 mm. The LRV of 0.2 mm membranes for SW8 and secondary ef¯uent cells was 3 and 1.5, respectively (total counts). Both membranes with pore sizes smaller than 0.2 mm acted similarly, they still transmitted secondary ef¯uent cells with LRV 2 log higher than 0.2 mm membranes, but for SW8 only 50% higher. In contrast to total count results, removal of bacteria was 100% with all membranes when assessed by cultureable counts, i.e. numbers of bacterial colonies recovered on R2A agar plates. Transmitted bacteria failed to grow on standard basal microbiology media most probably because they were injured during passage through the membranes to the extent that recovery in laboratory media did not occur. However, tests with CTC, an indicator of cell viability, indicated that approximately half of the cells of SW8 which passed the membranes had what appeared to be functional electron transfer chains in their membranes. All membranes had a pore size distribution which included pores larger than the nominal value. Field emission scanning electron microscopy (FESEM) provided evidence for entrapment of bacteria within the membrane matrix. # 0376-7388/99/$ ± see front matter # 1999 Elsevier Science B.V. All rights reserved. P I I : S 0 3 7 6 -7 3 8 8 ( 9 8 ) 0 0 2 5 1 -8

Membrane filtration has become firmly established as a primary technology for ensuring the purity, safety and efficiency of treatment of water or effluents. Water desalination is one of the major applications of this technology around the world. Several researches have been performed to develop and design membrane systems in order to increase the process accuracy and performance. In this research, the laminar fluid flow in porous tubes, a mode of crossflow filtration tubular membrane, is simulated numerically using the computational fluid dynamics (CFD) techniques. A two-dimensional numerical solution of the coupled Navier-Stokes, Darcy's law and mass transfer equation has been developed using control volume based finite difference method. Case study was performed for a microfiltration process. Prediction of the growth rate of the concentration polarization boundary layer along the length of tubular membranes has been performed. Effects of various operating conditions (e.g. geometrical dimension, required membrane surface area, Reynolds number and fouling) on the performance of membrane are studied and some comments on designing of such membranes are suggested.

Low-cost ceramic microfiltration membranes were prepared using clay of IIT Guwahati. Two membranes were prepared by paste casting followed by sintering at different temperatures, the first one from clay only (membrane A) and the second one from clay with small amounts of sodium carbonate, sodium metasilicate and boric acid (membrane B). Both the membranes were characterized by TGA, SEM, XRD, water permeability test and acid-base treatment. With the increase of sintering temperature, pore size as well as permeability and flexural strength were increasing while porosity and pore density were decreasing. The overall performance of membrane B was better than membrane A. The average pore size, porosity, pore density and flexural strength of membrane B sintered at 1000°C were 4.58 μm, 0.42, 2.06 × 10 10 m − 2 and 11.55 MPa respectively. This membrane was used for the removal of chromate from aqueous solutions by micellar enhanced microfiltration (MEMF) using cetylpyridinium chloride (CPC). 100% rejection of chromate ions were obtained at a feed ratio (CPC/chromate) of 10. Based on raw material prices, the membrane cost was estimated to be $19/m 2. The prepared low-cost membrane showed good promise for the treatment of wastewater containing such heavy metals.

Microfiltration (MF) of a fermentation broth containing Escherichia coli is reported in this article. We used a ceramic membrane filter (zirconia on sintered carbon) having a nominal pore size of 0.2 /zm. Our results indicate that the filtration resistance was mainly caused by the cake formed on the membrane surface. Both transmembrane pressure (TMP) and fluid sweeping velocity influenced this cake resistance. Resistances due to membrane itself and due to internal pore blockage by E. coli were less important and insensitive to both TMP and fluid sweeping velocity. Preliminary results also showed that the cell density could be significantly increased when we connected such a ceramic filter on-line with our fermentation system. In particular it was found that the gas bubbles entrained in the broth side of the filter could increase the filtration flux by as much as 80%.

Microfiltrations of Saccharomyces cerevisiae yeast particles of various deformabilities were conducted to examine the blocking mechanism due to particle deposition during the initial stage of the microfiltration process. The S. cerevisiae particles were treated with glutaraldehyde to form particles of various deformabilities. To compare differences in the blocking mechanisms among the different particles during microfiltration, a blocking model was adopted to estimate the filtrate flux, which accounts for initial blocking due to pore obstruction and subsequent blocking due to the growth of a cake over these initially blocked regions. The surface morphology of the cake layer on the membrane surface and the blockage by particles in membrane pores was examined by scanning electron microscopy (SEM). Analysis of the blocking mechanism of particles of varying deformability during microfiltration based on the blocking model indicated that softer particles resulted in more severe pore blocking problems and greater flux decline. A comparison of the theoretical results with experimental observations by SEM showed good qualitative agreement.

The use of a helical-shape baffle in a mineral (Carbosep) membrane provided an increase of more than 50% in permeate flux compared with that obtained without a baffle at the same hydraulic dissipated power. Two types of solutions were used: bakers yeast (5% dry weight) and dodecane-water emulsion (0.1%, w/w). The effect of the number of helices with respect to baffle length shows that the permeate volume increases with increasing number of helices but to a lesser degree when the number of helices is more than 4 per 25-mm baffle length. Also, when the baffle's maximum diameter was reduced by about 40% a small variation in permeate flux values was observed. More interesting results were obtained with experiments at very low transmembrane pressures (0.1-0.2 bar) when the permeate flux remained almost constant even from the begining of the experiment, indicating that progressive fouling was practically absent. Flow visualization was made with a video camera (VHS) and showed that the flow was rotational around the baffle axis and that the rotational velocity increased the mixing and migration of the rejected particles from the membrane surface. The manufacturing and installation of this type of baffle was found to be easy, and the cleaning time required for membrane regeneration was found to be shorter than after unbaffled steady flow experiments; so it was possible to recover the initial membrane permeability.

En este trabajo se describe el método de preparación y la caracterización de diversas membranas cerámicas tubulares con utilidad en el campo de la microfiltración. Se trata de membranas compuestas formadas por un soporte macroporoso que le confiere resistencia mecánica y una capa delgada microporosa o superficie activa depositada sobre el soporte que es la que determina las características retentivas de la membrana. Se prepararon diversas versiones de estas membranas a partir de materias primas cerámicas controlando, entre otras, variables como: el tamaño de partículas, la formulación química de la pasta y su tratamiento térmico. El material del soporte y de la capa activa se obtiene a partir de barbotinas a base de caolín, arcilla, feldespato, alúmina, etc. La morfología estructural del soporte, capa activa y membrana compuesta se ha estudiado mediante técnicas de AFM (Microscopía de Fuerza Atómica) y permeabilidades hidráulicas. Las propiedades estructurales y permeoselectivas de estas membranas cerámicas, hacen que sean apropiadas para procesos de microfiltración.

The exotic tropical fruits are adequate for the increasing market of fruit juices and based fruit drinks by their diversity of aromas and flavours and by their nutritional value. In such group, acerola appears as potentially attractive due to its high ascorbic acid content. The objective of this work was to develop a process for obtaining clarified and concentrated acerola juice, maintaining its nutritional and sensory characteristics. The experimental procedure consisted of fruits pulping followed by an enzymatic hydrolysis, a clarification by microfiltration and the concentration by reverse osmosis. The obtained products presented the required microbiological counts and nutritional quality due to the ascorbic acid preservation. Vitamin C content of the integral juice was 1234 mg/ 100 g and in concentrated juice it reached 5229 mg/100 g. In an acceptability test most of the consumers (84%) liked the drink prepared with the clarified juice.

NDMA LC-MS/MS Reverse osmosis Advanced treatment a b s t r a c t N-nitrosodimethylamine (NDMA) is a probable human carcinogen found in ng/l concentrations in chlorinated and chloraminated water. A method was developed for the determination of ng/l levels of NDMA using liquid chromatography-tandem mass spectrometry (LC-MS/MS) preceded by sample concentration via solid-phase extraction with activated charcoal. Recoveries were greater than 90% and allowed a method reporting limit as low as 2 ng/l. Using this method, the removal of NDMA was determined for the Interim Water Purification Facility (IWPF), an advanced wastewater treatment facility operated by the Orange County Water District (OCWD) in Southern California. The facility treats effluent from an activated sludge treatment plant with microfiltration (MF), reverse osmosis (RO), and an ultraviolet-hydrogen peroxide advanced oxidation process (UV-AOP). Six nitrosamines were surveyed: NDMA, N-nitrosomethylethylamine (NMEA), N-nitrosodiethylamine (NDEA), N-nitrosodi-n-propylamine (NDPA), N-nitrosopiperidine (NPip), and

The literature on chemical cleaning of polymeric hollow fibre ultrafiltration and microfiltration membranes used in the filtration of water for municipal water supply is reviewed. The review considers the chemical cleaning mechanism, and the perceived link between this and membrane fouling by natural organic matter (NOM)the principal foulant in municipal potable water applications. Existing chemical cleaning agents used for this duty are considered individually and their cleaning action described, along with the most commonly applied cleaning protocols (i.e. the cleaning conditions, cleaning sequence and method of cleaning agent application).

The ing and integration water ultrafiltration treatment construction of low-pressure (UF) facilities membranes has been and microfiltration new into water both treatexist(MF) and ultrafiltration (UF) membranes into both existing water treatment facilities and new water treatment plant construction has been rapidly gaining favor worldwide (AWWA, 2005). Contributing factors include the efficacy of these membranes in removing cysts and their consistent ability to produce low-turbidity product water despite variations in source water quality. One example of a decision to incorporate MF/UF technology into existing water treatment facilities is in Minnesota, where the Minneapolis Water Works has replaced aging granular media filters with UF at its 70mgd (265-ML/d) Columbia Heights Filtration Plant. Another example is in California, where the Modesto Irrigation District is doubling capacity from 36 to 72 mgd (136 to 273 ML/d) by adding membranes in parallel with existing granular media fil...

The trans membrane pressure (TMP) increase at a constant flux of 150 L m -2 h -1 due to membrane fouling by direct filtration with lake water is investigated for four ceramic (Al 2 O 3 , ZrO 2 , TiO 2 , SiC) and a PES/PVP polymeric microfiltration membrane(s). The membrane structures and compositions are characterized with permporometry (pore size, porosity) and XPS. The TiO 2 and SiC membrane have a 5 and 24 times larger average pore size than expected based on supplier information. The TMP increase rate due to fouling inversely follows the measured pore size. Reversible fouling decreases in the order of polymeric≈Al 2 O 3 ≈ZrO 2 >TiO 2 >SiC, and for irreversible fouling polymeric>ZrO 2 >Al 2 O 3 >TiO 2 >SiC. Removal of non purgeable organic carbon (NPOC) is around 30% for the ceramic membranes, and 13-25% for the polymeric membrane. The reversible NPOC load decreases in the following order (Al 2 O 3 >(ZrO 2 ≈TiO 2 ))≈SiC>polymeric. The higher degree of fouling on the polymeric membrane is partly due to its lower volume/area ratio, compared to ceramic membranes. Mass balance analysis shows that 858% of the NPOC is accounted for. Thus, the used soaking method (pH 12 NaOH, >1 hr) does not fully remove the NPOC, suggesting that a more aggressive cleaning solution should be used.

The oil extracted from olive paste is a turbid and opalescent must and contains impurities that can compromise its quality since they facilitate hydrolysis, fermentation and rancidity. Although filtration of this oil removes these otherwise damaging substances, it can also cause small changes in the oil. In this paper membrane cross-flow filtration is proposed as a different and innovative filtration process for extra virgin olive oil. The preliminary results reported here show that the removal of damaging substances through membrane filtration can be achieved in a single step, without the addition of filter aids (therefore reducing oil loss). Membrane filtration also does not alter the chemical composition of the oil.

Heat treatments are the established food technology for commercial processing of milk. However, degradation of valuable nutrients in milk (as proteins) and its sensory characteristics occur during these processes due to substantial heat exposure. The most important reactions that occur during milk heat treatment are the whey proteins denaturation, its interactions with the casein micelles and aggregation/dissociation of the casein micelles. Microfiltration represents an emerging food processing technology allowing gentle milk preservation at lower temperatures for similar, or better, nutritive value, microbial removal, and shelf stability. Thus, the aim of this work is to review the existing studies on the effects of microfiltration on milk proteins by comparing with the effects of heating treatments.

In the present study, the possibility to reuse the indigo dyeing rinsing wastewater originating from a denim textile mill was investigated. Coagulation and filtration processes were selected as the pretreatment alternatives and applied to dyeing wastewater samples. Both physicochemical pretreatment alternatives and nanofiltration technique were optimized to produce an effluent satisfying the reuse criteria for the textile industry. The results showed that coagulation is not an effective and efficient pretreatment due to high dose of coagulant requirement. Microfiltration (MF) through 0.45 mm pore-sized membrane provided 64% removal in color and 29% removal in COD leading to a color value of 2493 Pt-Co and COD of 892 mg/L in the permeate. Furthermore, ultrafiltration (UF) applied after MF revealed additional 62% color and 4% COD removals leading to a color value of 960 Pt-Co and COD of 856 mg/L. Hence, the sequential application of MF and UF and only MF as pretreatment alternatives were found to be promising prior to the application of nanofiltration (NF). NF experiments conducted using pretreated wastewater via only MF provided 99% color and 97% COD removals leading to a color of 15 Pt-Co and a COD of 20 mg/L and hence sequential application of MF and NF was found to be the optimum treatment scheme for the reuse of the dyeing wastewater of the studied textile mill and reuse criteria was satisfied.

The flow decline is studied in typical experiments with dead-end microfiltration of BSA solutions ( 1 and 0.1 kg/m 3) through Cyclopore ~ track-etched polycarbonate membranes (pore sizes 0.1, 0.2, 0,4 and 1.0 p.m) at pH 5 and with a saline content of NaC1 0.01 M. Results are examined, within the frame of the common blocking mechanisms, interpreted here as successive or simultaneous steps of flow decline rather than as alternative possibilities of theoretical modelling for experimental data.

This review reports all the analytical tools used for the membrane autopsies in seawater feed. Furthermore, we detail the possibilities of all the different types of new possibilities of pretreatments before reverse osmosis (RO) such as microfiltration, ultrafiltration, nanofiltration or membrane bioreactors. The last part gives an account of brine disposal and the possibilities of reusing RO modules for wastewater treatment. For this review a discussion about fresh water prices took place.

Membrane processes are increasingly reported for various applications in both upstream and downstream technology, such as microfiltration, ultrafiltration, emerging processes as membrane chromatography, high performance tangential flow filtration and electrophoretic membrane contactor. Membrane-based processes are playing critical role in the field of separation/purification of biotechnological products. Membranes became an integral part of biotechnology and improvements in membrane technology are now focused on high resolution of bioproduct. In bioseparation, applications of membrane technologies include protein production/ purification, protein-virus separation. This manuscript provides an overview of recent developments and published literature in membrane technology, focusing on special characteristics of the membranes and membrane-based processes that are now used for the production and purification of proteins.

Whey is a by-product of cheese production which is used mainly as animal feed or released into the wastewater treatment process, although it is rich in valuable components. Recent developments in membrane filtration have provided exciting new opportunities for large-scale protein and lactose fractionation. The aim of this research was to develop a complex membrane filtration technology for whey processing. The microfiltration and ultrafiltration processes were carried out with pilot-scale equipment. For these filtration procedures three modules -hollow-fibre, ceramic and spiral wound -were used. The permeates from micro-and ultrafiltration (MF and UF), and the original whey sample were filtered on nanofiltration (NF) and reverse osmosis (RO) equipment. After the measurements new methods for using whey were proposed. With this complex method cheese production can be redesigned to a more environmentally friendly and efficient process. All membrane filtration methods were used to find the potential applications of membrane systems for whey recycling and utilization.

This review focuses on the recent developments in the area of FOS research-its microbial production, functional properties and applications and an overview of the different analytical methods for the determination of the FTase. Different microbial sources of FTase reported in literature to produce FOS with different linkages to form 1-kestose, 6-kestose and neokestose in varying yields based on initial sucrose concentration is discussed. Different fermentative methods have been used for production of FOS. SSF has been used for the production of a value added product FOS utilizing various agroindustrial byproducts. The nutritional and culture parameters when optimized, the FOS yields and productivity could be improved. The use of immobilized enzymes and cells has led to the development of effective and economic methods for large-scale production of FOS. Forced flow Membrane reactor systems, biocatalyst system with a bioreactor equipped with a microfiltration systems, have been used for production of high content FOS by removing the released glucose and unreacted sucrose from the reaction mixture resulting in up to 98% FOS. The use of mixed enzyme system of Fructosyl Transferase and glucose oxidase or glucose dehydrogenase, could produce highly concentrated FOS up to 90-98%. Nano-filtration for removing glucose resulted in FOS of 90% concentration. The purified enzyme was found to produce kestose and nystose unlike the crude enzyme which produced GF 5 and GF 6 oligosaccharides Kinetic parameters (V m , K m , and K i ) of the enzyme were determined from experimental data on the transfructosylation rate at various substrate concentrations with and without addition of glucose Techniques like HPLC, using polar-bonded phase and resin-based HPLC columns are commonly used for separation of oligosaccharides with refractive Index Detector or pulsed amperometric detector and annular size exclusion chromatography for large scale and continuous fractionation. Other techniques like gas liquid chromatography, thin layer chromatography, NMR and Mass Spectrometry have been used for structure analyses. The functional properties like use as prebiotics, dietary fiber, role in absorption and defense/Immunity, lipid metabolism control of diabetics have been discussed. A variety of applications in food formulations are also discussed.

Membrane separation technology offers a potential application in the processing of crude palm oil. Ceramic membranes with different pore diameters (0.45 and 0.2 micron) were used to conduct the study on micromembrane process. Quality parameters of membrane-processed oils examined included free fatty acid (FFA), carotene, fatty acid composition (FAC), phosphorus and iron contents. The effect of operating parameters such as transmembrane pressure, feed flow and time on permeate flux were evaluated. It was found that ‘Ceraflo’ceramic membrane with a pore size of 0.45 micron was only able to reject 14% of phosphorus from the crude oil. Ceramic membrane with pore size of 0.2 micron showed a better phosphorus rejection of 56.8%. The permeate was found to contain 7.13 ppm of phosphorus. The 0.2 micron membrane was also able to remove more than 80% of the iron from crude palm oil. Pore sizes for both membranes were not small enough to remove other components such as FFA, and carotene. Both membranes showed a similar trend in which the permeate flux increased with transmembrane pressure and feed flow until a certain limit where the flux declined with increasing pressure and feed flow. The limits in transmembrane pressures for membrane with pore sizes of 0.45 and 0.2 micron were 1.65 and 1.25 bar, respectively. Whereas the limits in feed flow for 0.45 micron and 0.2 micron membranes were 9.2 and 9.8 L/min

Hollow fiber membrane modules have had many applications, such as filtration, extraction, and oxy- genation, in numerous industrial processes for many years. As bioreactors, they are extensively used for enzyme reactions and cell/bacteria/yeast culture. The concept of a hollow fiber membrane bioreactor (HFMB) used in cell culture is shown in Figure 1.
The hollow fiber membranes are contained in an external shell (normally in the shape of a cylinder). The cells can be attached to the outer surface of the membranes, or more commonly maintained in the extracapillary space (ECS). Nutrients flow in the lumen of the fibers and can diffuse out through the pores of the fiber wall to feed the cells. Also, the metabolic waste produced by cells can permeate back into the fibers and be carried away.
HFMBs have been used to culture a variety of mammalian cell lines since their inception by Knazek [1]. HFMBs for mammalian cell cultures are mainly used to produce expensive biochemicals such as vac- cines [2], interferons [3], hormones [4], growth factors [5], viruses [6], and monoclonal antibodies [7] and to act as artificial organs [8, 9].
There are many advantages which HFMBs offer over other culture methods. HFMBs have high sur- face-to-volume ratios of around 30 cm2/cm􏰀3 [10], thus giving the potential to grow cells to high densities.
The continuous supply of uniform liquid and gaseous nutrients and removal of metabolic wastes provide a stable microenvironment for cells. The selective perme- ability property can protect cell culture from the immune system in artificial organ applications and to facilitate the recovery in biological product manufacture [11]. Cells are subject to low shear forces due to their separation from the nutrient flow in the fiber lumen.
More recently, HFMB found its application in the area of regenerative medicine. Generally speaking, regenerative medicine includes either engineered functional tissues or therapeutic quantities of cells. Tissue engineering applications aim at developing functional tissues from cells in combination with a suitable matrix to support and accelerate regenera- tive healing, while cell therapy only transplants required type and amount of cells into the defect site. This chapter presents a summary on the appli- cation of HFMBs in regenerative medicine, as an enabling technology to support three-dimensional (3D) tissue culture and to expand stem cells.

Conventional processes are widely used as pretreatment for reverse osmosis (RO) desalination technology since its development. However, these processes require a large footprint and have some limitation issues such as difficulty to maintain a consistent silt density index, coagulation control at low total suspended solids, and management of higher waste sludge. Recently, there has been a rapid growth in the use of low-pressure membranes as pretreatment for RO systems replacing the conventional processes. However, despite the numerous advantages of using this integrated membrane system mainly providing good and stable water quality to RO membranes, many issues have to be addressed. The primary limitation is membrane fouling which reduces the permeate flux; therefore, higher pumping intensity is required to maintain a consistent volume of product. This paper aims to optimize the permeation flux and cleaning frequency by providing high permeate quality. Different low-pressure polyethersulfone membranes with different pore sizes ranging from 0.1 lm to 50 kDa were tested. Eight different filtration configurations have been applied including the variation of coagulant doses aiming to control membrane fouling. Results showed that all the configurations with/without coagulation, provided permeate with excellent water quality which improves the stability of RO performance. However, more stable fluxes with less-energy consumption were achieved by using the 0.1 lm and 100 kDa membranes with 1 mg/L FeCl 3 coagulation. The use of UF membranes, having tight pores, without coagulation also proved to be an excellent option for Red Sea water RO pretreatment.

The use of an automated multiwell method for assessing the normal flow filtration of purified DNA solutions containing plasmids and bacterial artificial chromosomes is presented. The custom multiwell filter design (filtration area of 0.28 cm 2 per well) allowed the use of low DNA volumes and that experimental replicates be performed simultaneously with parallel analysis of multiple parameters. Using the multiwell system, the behaviour of purified DNA solutions was studied when operating pressure, vectors size and membrane type was varied. Operating pressures of 30-65 kPa were applied and showed little effect on membrane capacity. Flux and membrane capacity decreased significantly with increasing vector size (6-72 kb). Filtration using different 0.2-or 0.22-m rated polyvinylidene difluoride and polyethersulfone membranes were evaluated and the results showed difference in flux and transmission rates. Results were verified against conventional membrane filter capsules with larger filtration areas of 0.65 and 3.9 cm 2 . Information on filter capacity was comparable between the multiwell and conventional systems. This is particularly useful at the early stages of product development where only limited amounts of material are available. By conducting the experiments on a robotic platform, automated liquid sensing, continuous feeding and integration of analysis techniques were enabled.

This study investigated the contribution of microfiltration to phosphorus removal in the sequencing anoxic/anaerobic membrane bioreactor. The phosphorus content in activated sludge was fractionated by the Schmidt-Thannhauser-Schneider method. The size distribution of phosphorus in the influent was analyzed to estimate the portion of particulate phosphorus rejected physically by the 0.2 lm microfiltration. The result was that along with the high removal of phosphorus (83%) the phosphorus content of activated sludge was measured as 58.66 mgP/gVSS corresponding to 5.87% on dry weight basis. About 9% of total phosphorus was chemically precipitated phosphates while 56% was stored inside the microbial cell by activity of PAOs, and 35% was the sum of minor intracellular compositions and the particulate residuals, which could be rejected completely by the microfiltration. The biological activity is the dominant way of phosphorus removal in the process. However, the microfiltration also contributed significantly to phosphorus removal by retaining the particulate phosphorus inside the system.