Use Of Microfiltration Research Articles

The concept of microfiltration of hydraulic oil in rail vehicles

The article presents the issue of microfiltration of hydraulic oil from metallic impurities and water that deteriorate the properties of the oil. Tests carried out on oils have shown that periodic oil replacement in machines or vehicles in accordance with their maintenance documentation ensures that the system is emptied of 95% of impurities from the old oil before pouring the new one. The remaining part, i.e. 5% of impurities, together with the oil remaining on the walls of the pipes or inside other hydraulic devices, will mix with the new oil, reducing its cleanliness class. Periodic replacement of hydraulic oil will not allow for complete cleaning of the system. In extreme cases, poor oil condition may cause disruptions in the operation of the machine with the hydraulic system or its downtime for oil replacement or repair. Filtering the oil in the system while the machine is running will clean the oil from impurities and water, extend the oil's service life, without disabling the hydraulic system. The article includes, among others: The justification for the use of microfiltration of hydraulic oil with portable filtering devices in order to extend the service life of the oil until the next replacement is presented. The main purpose of the article is to present the methodology for testing hydraulic oil in accordance with the requirements of ISO, NAS and SAE in order to assign the oil to a given cleanliness class. Additionally, the results of testing the oil cleanliness class in various periods of operation of the machine with the hydraulic installation on a portable measuring device were presented.

Investigating the Fouling Models of the Microfiltration Mixed Matrix Membranes-Based Oxide Nanoparticles Applied for Oil-in-Water Emulsion Separation

Membrane fouling is a major problem encountered in the use of microfiltration (MF) processes to separate the emulsified oil from water. This work involves assessing the efficacy of removing oil-in-water emulsion (O/W emulsion), and evaluating fouling resistance by studying the membrane morphology before and after fouling, and after washing with different cleaning solutions via field emission scanning electron microscopy (FESEM) analysis. Also, the fundamental mechanism involved in the flux drop during crossflow MF has been assessed using models such as the Hermia blocking models and the modified model by Field. The standard and intermediate pore blocking models provided the best prediction for experimental behavior when analyzing the decay in the flux with time for the bio silicon oxide/polyvinylchloride (B-SiO2/PVC) membrane and the stannic oxide/polyvinylchloride (SnO2/PVC) membrane. This research established regression equations of the flux for both membranes in which these equations are highly correlated with R2 of 98.33% for B-SiO2/PVC and R2 of 99.52% for SnO2/PVC using the surface response methodology (RSM). The high flux recovery ratio (FRR) is indicative of the improved antifouling feature of the manufactured membranes where it was 96.8% for B-SiO2/PVC and 94.6% for SnO2/PVC. The results obtained by Hermia and Field were in good agreement with RSM analysis supporting the standard pore-blocking mechanism.

The Use of Microfiltration for the Pretreatment of Backwash Water from Sand Filters.

Tests of microfiltration efficiency used for the pretreatment of backwash water from sand filters were conducted at two water treatment plants treating surface water and infiltration water. Microfiltration efficiency was evaluated for three membrane modules: two with polymeric membranes and one with a ceramic membrane. This study showed that the contaminants that limit the reuse of backwash water from both plants by returning them to the water treatment line are mostly microorganisms, including pathogenic species (Clostridium perfringens). Additionally, in the case of backwash water from infiltration water treatment, iron and manganese compounds also had to be removed before its recirculation to the water treatment system. Unexpectedly, organic carbon concentrations in both types of backwash water were similar to those present in intake waters. Microfiltration provided for the removal of organic matter, ranging from 19.9% to 44.5% and from 7.2% to 53.9% for backwash water from the treatments of surface water and infiltration water, respectively. Furthermore, the efficiency of the iron removal from backwash water from infiltration water treatment was sufficient to ensure good intake water quality. On the other hand, manganese concentrations in the backwash water, from infiltration water treatment, pretreated using the microfiltration process exceeded the levels found in the intake water and were, therefore, an additional limiting factor for the reuse of the backwash water. In both types of backwash water, the number of microorganisms, including Clostridium perfringens (a pathogenic one), was a limiting parameter for backwash water reuse without pretreatment. The results of the present study showed the possibility for using microfiltration for the pretreatment of backwash water, regardless of its origin but not as the sole process. More complex technological systems are needed before recirculating backwash water into the water treatment system. The polyvinylidene fluoride (PVDF) membrane proved to be the most effective for DOC and microorganism removal from backwash water.

Gravity-Driven Membrane as seawater desalination pretreatment: Understanding the role of membrane biofilm on water production and AOC removal

Gravity-Driven Membrane (GDM) is considered an emerging seawater reverse osmosis desalination pretreatment. The objective of this study was to assess the GDM process performance under different operating conditions and to evaluate the impact of membrane biofilm on the produced water quantity and quality. Three lab-scale submerged GDM systems (UF12h, UF24h and MF24h) were tested under different conditions of Hydraulic Retention Time (HRT) (12 h/24 h) and membrane pore size (Microfiltration/Ultrafiltration). The best water quality in terms of Assimilable Organic Carbon (AOC) was achieved with the longer HRT (24 h), where significant AOC was removed by the biofilm developed on the membrane. The next generation sequencing indicated that a longer HRT increased the abundance of Proteobacteria and Planctomycetes in the biofilm, which due to their biodegradation capability yielded to the highest AOC removal (~50–55 %). Furthermore, the use of microfiltration led to the highest water production (9.1 L/m2/h) due to larger membrane pore size, and a less dense biofilm. These findings indicate that employing a microfiltration membrane and 24 h HRT provides the best performance in terms of water quantity and AOC-removal. This study demonstrates that controlling GDM design and operation enabled manipulation of the biofilm proprieties yielding to high water production and high AOC-removal.

Slower proteolysis in Cheddar cheese made from high-protein cheese milk is due to an elevated whey protein content.

A growing number of companies within the cheese-making industry are now using high-protein (e.g., 4-5%) milks to increase cheese yield. Previous studies have suggested that cheeses made from high-protein (both casein and whey protein; WP) milks may ripen more slowly; one suggested explanation is inhibition of residual rennet activity due to elevated WP levels. We explored the use of microfiltration (MF) to concentrate milk for cheese-making, as that would allow us to concentrate the casein while varying the WP content. Our objective was to determine if reducing the level of WP in concentrated cheese milk had any impact on cheese characteristics, including ripening, texture, and nutritional profile. Three types of 5% casein standardized and pasteurized cheese milks were prepared that had various casein:true protein (CN:TP) ratios: (a) control with CN:TP 83:100, (b) 35% WP reduced, 89:100 CN:TP, and (c) 70% WP reduced, 95:100 CN:TP. Standardized milks were preacidified to pH 6.2 with dilute lactic acid during cheese-making. Composition, proteolysis, textural, rheological, and sensory properties of cheeses were monitored over a 9-mo ripening period. The lactose, total solids, total protein, and WP contents in the 5% casein concentrated milks were reduced with increasing levels of WP removal. All milks had similar casein and total calcium levels. Cheeses had similar compositions, but, as expected, lower WP levels were observed in the cheeses where WP depletion by MF was performed on the cheese milks. Cheese yield and nitrogen recoveries were highest in cheese made with the 95:100 CN:TP milk. These enhanced recoveries were due to the higher fraction of nitrogen being casein-based solids. Microfiltration depletion of WP did not affect pH, sensory attributes, or insoluble calcium content of cheese. Proteolysis (the amount of pH 4.6 soluble nitrogen) was lower in control cheeses compared with WP-reduced cheeses. During ripening, the hardness values and the temperature of the crossover point, an indicator of the melting point of the cheese, were higher in the control cheese. It was thus likely that the higher residual WP content in the control cheese inhibited proteolysis during ripening, and the lower breakdown rate resulted in its higher hardness and melting point. There were no major differences in the concentrations of key nutrients with this WP depletion method. Cheese milk concentration by MF provides the benefit of more typical ripening rates.

Pilot-scale experiments on a hybrid membrane-electrocoagulation system to produced water treatment in a domestic oil reservoir

Abstract The goal of this paper is to design and set up a new hybrid treatment system for purification of Iranian offshore oil company wastewater. The treatment system consists of electrocoagulation, microfiltration and reverse osmosis (RO) sections. Treatment performance is evaluated by measuring electrical conductivity (EC), chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total suspended solids (TSS), total dispersed solids (TDS) oil and grease (O&G), total hardness (TH) and turbidity. Results showed that the maximum removal efficiency of BOD5, COD, TSS, O&G, EC, TH and turbidity were obtained as 94.49%, 92.17%, 88.18%, 80.8%, 89.84%, 86.66% and 71.72%, respectively. DO was increased significantly due to the reduction of BOD, COD and microorganisms. Results showed that the combination of iron and aluminium electrodes can be very effective in removing pollutants. In addition, the use of microfiltration before RO led to a significant reduction in salinity and TDS. Response Surface Methodology (RSM) was used to determine the optimal experimental conditions for COD, BOD5 and turbidity using Design Expert11. RSM results showed that the optimal electric current and time for BOD5 and COD removal is 20A and 300 min, respectively. The optimal electric current and time for turbidity were obtained as 20A and 210 min.

Wastewater Treatment and Biogas Recovery Using Anaerobic Membrane Bioreactors (AnMBRs): Strategies and Achievements

Anaerobic digestion is one of the most essential treatment technologies applied to industrial and municipal wastewater treatment. Membrane-coupled anaerobic bioreactors have been used as one alternative to the conventional anaerobic digestion process. They are presumed to offer the advantage of completely reducing or minimizing the volume of sludge and increasing biogas production. However, researchers have consistently reported different kinds of fouling that resulted in the reduction of membrane life span. Depending on the strength of the effluent, factors such as high suspended and dissolved solids, fats, oil and grease, transmembrane pressure (TMP) and flux were reported as major contributors to the membrane fouling. Moreover, extracellular polymeric substances (EPSs) are an important biological substance that defines the properties of sludge flocs, including adhesion, hydrophobicity and settling and have been found to accelerate membrane fouling as well. Extensive studies of AnMBR have been done at laboratory while little is reported at the pilot scale. The significance of factors such as organic loading rates (OLRs), hydraulic retention time (HRT), pH and temperature on the operations of AnMBRs have been discussed. Microbial environmental conditions also played the most important role in the production of biogas and the chemical oxygen demand (COD) removal, but adverse effects of volatile fatty acids formation were reported as the main inhibitory effect. Generally, evaluating the potential parameters and most cost effective technology involved in the production of biogas and its inhibitory effects as well as the effluent quality after treatment is technically challenging, thus future research perspectives relating to food to microorganism F/M ratio interaction, sufficient biofilm within the reactor for microbial attachment was recommended. For the purpose of energy savings and meeting water quality discharge limit, the use of micro filtration was also proposed.

Dairy wastewater treatment using integrated membrane systems

This work evaluated the performance of double-stage integrated filtration systems using membranes. The integrated systems comprise the sequential use of microfiltration (MF) plus nanofiltration (NF) and MF plus reverse osmosis (RO) under different pressures for treating dairy wastewater. The MF+NF system reduced 100% turbidity, 96% color, 58% total Kjeldahl nitrogen (TKN) and 51% chemical oxygen demand. The MF+RO system reduced 100% turbidity, 100% color, 94% TKN and 84% total organic carbon. Therefore, the MF+RO system was more efficient to retain total solids and organic matter. The performance of the systems was also evaluated in terms of permeate flux under 1 and 2bar (MF membrane) and under 20 and 30bar (NF or RO membranes). Overall, a flux decline was observed in the first 30min. Thereafter, the flux remained relatively constant until 60min. The retention was higher in lower pressures, enabling a more purified permeate wastewater that could be disposed of in receiving water according to the Brazilian environmental regulations or reused in Cleaning In Place systems.

Performance of commercial composite hydrophobic membranes applied for pervaporative reclamation of acetone, butanol, and ethanol from aqueous solutions: Binary mixtures

Abstract In this study the efficiency of three various commercial membranes based on poly(octylmethyl siloxane), poly(ether-block-amide), and poly(dimethylsiloxane) polymers were investigated in pervaporative separation of acetone, butanol, and ethanol from aqueous binary solutions (0–5 wt% of organics) at 60 °C. The influence of fermentation broth microfiltration on membrane performances in pervaporative removal of ethanol was also investigated. The use of microfiltration improved the effectiveness of the removal of ethanol from the broth comparing with the unfiltered one. Molar ratios of organics to water fluxes and Pervaporative Separation Index (PSI) values were employed to discuss membranes' performance in removal of organic solvents from binary aqueous mixture. It was found that PDMS based (Pervap4060) membrane shows the best separation efficiency in all tested binary aqueous mixtures. Modelling of the process proved the feasibility of pervaporation process for the removal of acetone, butanol and ethanol from binary and quaternary aqueous mixtures.

Treatment of Bisphenol A-Containing Effluents from Aerobic Granular Sludge Reactors with the Use of Microfiltration and Ultrafiltration Ceramic Membranes

This study investigated the use of ceramic membranes to remove total suspended solids (TSS), organics (expressed by chemical oxygen demand, COD), and bisphenol A (BPA) via microfiltration (MF, pore size 0.45 μm) and ultrafiltration (UF, cutoff 150 kDa) in post-treatment of effluents from aerobic granular sludge reactors (GSBRs). The efficiency of removal of COD, BPA, and TSS in MF was similar to that in UF; however, it was achieved at a lower pressure, which reduces energy consumption during the filtration process. Despite the similar quality of the permeates in MF and UF, the permeate flux averaged almost 20% higher in UF than in MF. The rejection coefficients were 77–82% for COD and 48–100% for BPA. In both MF and UF, TSS were totally removed. In the integrated system of aerobic granular sludge reactor and membrane installation, total removal of COD was 92–95% and that of BPA was above 98%, independently of the membrane technique. The high efficiency of BPA removal in MF and UF, despite pore sizes in the MF and UF membranes larger than the BPA molecules, suggests that some part of the BPA was first bound by particulate organic matter in the biologically treated wastewater before this sorbed form was removed by the membranes. Furthermore, the high removal of COD and BPA, even in MF, was attributed to adsorption on the membranes, in addition to sieve retention.

Discussion between alternative processing and preservation technologies and their application in beverages: A review

The alternative technologies discussed in this review are able to eliminate pathogenic bacteria while retaining bioactive compounds such as anthocyanins, phenols, pigments, and vitamins, improve the extraction processes of fruit or vegetable juices. The use of nonthermal processing technologies in beverages might provide a higher quality value to the final product and consumers tended to prefer more natural products with minimum preservative substances. This review is analyze and discuss the advantages and disadvantages of alternative technologies applied in beverages, evaluating the parameters that can optimize beverage processing such as time, temperature, pressure, frequency, tension, among others. Additionally, finding solutions to beverage processing issues will be considered analyzing the results obtained with other applied methods, and an overview of new strategies such as microfiltration or the combination of two alternative technologies to improve the quality of the final product will also be evaluated. Practical applications The applications of alternative technologies mentioned in this article, are a feasible option for the preservation of beverages in the area of industry. The capacity of each of them has been demonstrated, in addition to the use of microfiltration and ultrafiltration, but the combination between them sounds very encouraging to achieve the quality and safety of beverages, with an extended shelf life and greater protection of its main components. This provides a wide range of research opportunities for any type of beverage.

Successive membrane separation processes simplify concentration of lipases produced by Aspergillus niger by solid-state fermentation.

In this study, we developed a simplified method for producing, separating, and concentrating lipases derived from solid-state fermentation of agro-industrial residues by filamentous fungi. First, we used Aspergillus niger to produce lipases with hydrolytic activity. We analyzed the separation and concentration of enzymes using membrane separation processes. The sequential use of microfiltration and ultrafiltration processes made it possible to obtain concentrates with enzymatic activities much higher than those in the initial extract. The permeate flux was higher than 60L/m2 h during microfiltration using 20- and 0.45-µm membranes and during ultrafiltration using 100- and 50-kDa membranes, where fouling was reversible during the filtration steps, thereby indicating that the fouling may be removed by cleaning processes. These results demonstrate the feasibility of lipase production using A. niger by solid-state fermentation of agro-industrial residues, followed by successive tangential filtration with membranes, which simplify the separation and concentration steps that are typically required in downstream processes.

Tratamento Avançado de Efluente de Reator UASB por Membrana de Microfiltração Associado à Desinfecção por Radiação Ultravioleta

A baixa eficiência dos reatores UASB, no que se refere às remoções de nutrientes, patogênicos e matéria orgânica, faz com que seja necessário o pós-tratamento, a fim de melhorar a qualidade do efluente gerado. Assim sendo, investigou-se nesse estudo a utilização da microfiltração associada à desinfecção por radiação ultravioleta como alternativa ao tratamento avançado de esgotos. Para isso, foram coletadas amostras de efluente de reator UASB a fim de realizar ensaios em sistema piloto de microfiltração, utilizando-se em uma das amostras a pré-coagulação com tanino vegetal. Posteriormente todas as amostras microfiltradas foram introduzidas em reator UV, aplicando-se doses de radiação variando de 43,8 a 194,9 mWs.cm<sup>-2</sup> para simular a desinfecção. O sistema empregado mostrou bons resultados em termos de remoção de turbidez, cor aparente, cor verdadeira, fósforo, NTK, ST, SST e DQO, atingindo na melhor condição operacional, os seguintes valores respectivamente: 1,90 uT, 15 uC, 10 uC, 0,94 mg/L, 17,64 mg/L, 123 mg/L, 0 mg/L e 10 mg/L, que representaram os seguintes percentuais de remoção 91,3%, 93,6%, 82,0%, 60,0%, 26,3%, 87,9%, 100% e 86,1% respectivamente. A inativação de <em>E. coli,</em> coliformes totais, colifagos e <em>Clostridium perfrigens</em> obtida foi satisfatória, atingindo inativação maior que o limite de detecção do método utilizado quando submetida às maiores doses de radiação testadas. Os valores médios de fluxo de permeado variaram de 55,2 até 133,6 L.m<sup>-2</sup>.h<sup>-1</sup>

A scale-down cross-flow filtration technology for biopharmaceuticals and the associated theory

Use of microfiltration (MF) and ultrafiltration (UF) in cross-flow mode has been intensifying in downstream processing for expensive biopharmaceuticals. A scale-down cross-flow module with ring channel was constructed for reducing costs and increasing throughput. Commensurate with its validation, a new scale down (or scale up) theoretical framework has been further developed to 3 operational parities: (1) ratio of initial sample volume to membrane area, (2) shear force adjacent to membrane surface, and (3) initial permeate flux. By keeping identical initial physicochemical properties, we show that these 3 operational parities are equivalent to 2 further time-dependent theoretical parities for flux and transmission respectively. Importantly, transmission sensitively reflects membrane conditions for partially transmissible molecules or particles. Computational fluid dynamics simulation was conducted to confirm nearly identical shear forces for the mini and its reference filters. Permeate fluxes in suspension containing Escherichia coli phage T7, a monoclonal antibody (MAb) or other proteins, and transmission (with phage T7) were measured. For application demonstration, diafiltration and concentration modes were applied to the MAb, and separation mode to a mixture of bovine serum albumin and lysozyme. In conclusion, the developed scale-down filter has been shown to behave identically or similarly to its reference filter.

Removal of radionuclides and corrosion products from neutral and weakly alkaline solutions by microfiltration

The use of microfiltration for removing from solutions Cs, Sr, Co, Zr, Ce, and Pu radionuclides and corrosion products, Fe(III) compounds, was studied. The microfiltration method is efficient for removing radionuclides of readily hydrolyzable elements (Co, Zr, Ce, Pu, etc.) from neutral or weakly alkaline solutions. In the presence of freshly precipitated iron(III) hydroxide, the decontamination efficiency is still higher, reaching 97–99%. High (99.5%) efficiency of the retention of the apparatus corrosion product, finely dispersed precipitate of iron(III) hydroxide, by a microfiltration membrane in treatment of lithium salt solutions was demonstrated. The microfiltration is inefficient in removal of ionic species of Cs and Sr radionuclides. For the removal of these radionuclides by microfiltration, the use of collectors capable of specific adsorption of these radionuclides was suggested, namely, the use of potassium nickel ferrocyanide precipitate for Cs radionuclides and of manganese dioxide and barium sulfate precipitates for Sr radionuclides. The efficiency of the removal of 137Cs and 85Sr radionuclides using specific collectors reaches 97–99%.

Use of Microfiltration to Improve Quality and Shelf Life of Ultra-High Temperature Milk

The main objectives of this research were to evaluate the efficacy of microfiltration in extending the shelf life and improving the quality of ultra-high temperature (UHT) milk. Results showed that in high somatic cell counts (SCC) and low SCC raw milk, microfiltration resulted in an average 3.56 and 3.57 log reduction of total bacterial counts, and 1.52 × 106 and 2.10 × 105 to <1.00 × 103 of SCC, respectively. Microfiltered UHT milk had higher pH values and lower titratable acidity compared to nonmicrofiltered UHT control milk during storage. After 112 days and 63 days of storage, there were significant differences of noncasein nitrogen/total nitrogen between the microfiltered UHT milk and nonmicrofiltered UHT control milk in high SCC and low SCC milk (P < 0.05). Particle size distribution in microfiltered UHT milk followed monodisperse distribution during storage. The shelf life of microfiltered UHT milk made by low SCC and high SCC raw milk were effectively extended by 21 and 63 days. Practical Applications Microfiltration process was to reduce bacteria and to remove somatic cell counts (SCC) of raw milk. Compared with nonmicrofiltered ultra-high temperature (UHT) control milk, the quality of microfiltered UHT milk was greatly enhanced. Microfiltration in combination with UHT process resulted in longer shelf life of UHT milk, especially for high SCC milk.

Avaliação do emprego de microfiltração para remoção de fibras do efluente de branqueamento de polpa celulósica

O processo de branqueamento é o estágio em que ocorre a maior perda de fibras durante a fabricação de polpa celulósica. Além de ser uma perda de produto, estas fibras aumentam a concentração de matéria orgânica do efluente dificultando seu tratamento. O objetivo deste trabalho foi avaliar o emprego de microfiltração (MF) na remoção de fibras de efluente de branqueamento alcalino de polpa celulósica. Foi empregada membrana de poli(éter imida) com tamanho médio de poros de 0,5 µm e área de filtração de 0,05 m². O efeito das condições operacionais no fluxo permeado foi avaliado através do monitoramento do perfil de fluxo durante a operação em diferentes condições de velocidade de escoamento (Reynolds de 1.226, 1.653 e 2.043), pH da alimentação (7, 10 e 10,6), temperatura (28, 43 e 48°C) e pressão de operação através da avaliação da pressão crítica. Os resultados mostraram que a MF é um processo eficiente para remoção de fibras, apresentado 99% eficiência de remoção de sólidos suspensos. O melhor desempenho da operação de MF foi obtido empregando pH 7, pressão de 1 bar e Re de 1.653. Os resultados mostram que a redução do fluxo se deve principalmente à formação de torta.

Feasibility of using an innovative PVDF MF membrane prior to RO for reuse of a secondary municipal effluent

The use of microfiltration (MF) or ultrafiltration (UF) prior to reverse osmosis (RO) process for reuse of reclaimed water is becoming increasingly attractive. In this work, a secondary municipal effluent was treated by a pilot-scale continuous filtration system with an innovative polyvinylidene fluoride (PVDF) MF membrane prepared via thermally induced phase separation (TIPS) method. The study showed that the MF system was operated under low normalized trans-membrane pressure (substantially below 40kPa) and high permeate flux (52–60L/m2/h). The MF system was able to treat the secondary effluent of unstable quality with good system stability. The membrane's permeability was easily recovered by chemical enhanced backwash (CEB) at a low effective chorine concentration (300 or 500mg/L). The membrane exhibited excellent mechanical strength and strong chemical resistance throughout the investigation. The treated water from the MF system exhibited stable quality with turbidity less than 0.05NTU, 15-minute silt density index (SDI15) less than 3 and chemical oxygen demand (CODCr) less than 15mg/L. The treated water quality completely met the quality requirement of RO feed water. This work demonstrated the feasibility of using the innovative MF membrane prior to RO for reuse of the secondary municipal effluent.

Treatment of Bleach Pulp Mill Effluent by MF‐MBR

The types of treatment most commonly used by pulp mills are biological treatments in combination with sedimentation or coagulation/flocculation as pretreatment. The main issues faced by these types of treatment are low efficiency in the removal of organic matter and the loss of aggregate value for the recovered fiber. Therefore, this study aims to evaluate the use of microfiltration (MF) combined with a membrane bioreactor (MBR) for the treatment of bleach pulp mill effluents. The results showed that the use of the MF-MBR system was an excellent alternative for the treatment of bleach pulp mill effluents with an average COD removal of 95%. The microfiltration allowed the recovery of fibers, which can be returned to the production process without losing economic value, and produced a better quality effluent for further treatment in the MBR. The MBR presented high efficiency removal of organic matter.

Enhancement of textile wastewater treatment process using Nanofiltration

In the present work, the performances of the use of Nanofiltration (NF) as a post treatment after Coagulation–flocculation (CF) which was used to treat a mixture of effluents coming from different textile industry operations (dying, bleaching…), are studied. At first, the fluctuation of the characteristics of the different effluents coming from the different treatment steps of cotton clothes is determined. Then, the effects of operating conditions, like pressure and temperature on the permeate flux and retention of chemical oxygen demand (COD), color and salinity are investigated. Critical flux concept is used to study the effect of salt on the performance of Nanofiltration. It is concluded that it is more difficult to eliminate the salts when the concentration is higher than 9 g/L. The Nanofiltration experiments showed that the permeate flux was about 24 L/h.m 2 obtained at a Volume Reduction Factor (VRF) of 3 under optimal pressure and temperature of 10 bar and 40 °C. The best pollutant retention was: 57% for COD, 100% for color and 30% for salinity. Finally, it is demonstrated that the use of Microfiltration (MF) instead of Coagulation–flocculation as pretreatment prior to Nanofiltration leads to the enhancement of the effluent treatment performances mostly regarding to salinity and COD retention.