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1
Park, J., S. Takizawa, H. Katayama, and S. Ohgaki. "Biofilter pretreatment for the control of microfiltration membrane fouling." Water Supply 2, no. 2 (April 1, 2002): 193–99. http://dx.doi.org/10.2166/ws.2002.0063.
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A pilot scale biofilter pretreatment - microfiltration system (BF-MF) was operated to investigate the effect of biofilter treatment in fouling reduction of microfiltration. Biofiltration was expected to reduce the membrane fouling by removal of turbidity and metal oxides. The hollow-fiber MF module with a nominal pore size of 0.1 μm and a surface area of 8m2 was submerged in a filtration tank and microfiltration was operated at a constant flux of 0.5 m/d. Biofiltration using polypropylene pellets was performed at a high filtration velocity of 320 m/d. Two experimental setups composed of MF and BF/MF, i.e. without and with biofilter pretreatment, were compared. Throughout the experimental period of 9 months, biofilter pretreatment was effective to reduce the membrane fouling, which was proved by the result of time variations of trans-membrane pressure and backwash conditions. The turbidity removal rate by biofiltration varied between 40% to 80% due to the periodic washing for biofilter contactor and raw water turbidity. In addition to turbidity, metals, especially Mn, Fe and Al were removed effectively with average removal rates of 89.2%, 67.8% and 64.9%, respectively. Further analysis of foulants on the used membranes revealed that turbidity and metal removal by biofiltration was the major effect of biofiltration pretreatment against microfiltration fouling.
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Gesan, Genevieve, Georges Daufin, Uzi Merin, Jean-Pierre Labbe, and Auguste Quemerais. "Microfiltration performance: physicochemical aspects of whey pretreatment." Journal of Dairy Research 62, no. 2 (May 1995): 269–79. http://dx.doi.org/10.1017/s0022029900030971.
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SUMMARYClarification of whey by microfiltration (MF) can be achieved after appropriate pretreatment of the feed. A control pretreatment consists of a physicochemical process comprising increased ionic calcium and pH accompanied by heat (50 °C, 15 min) to cause aggregation of complex lipid–calcium phosphate particles, which are then separated by MF. This pretreatment process was modified by increasing the temperature to 55 °C and by maintaining the pH constant during heat treatment. This modification resulted in larger calcium phosphate particles and a lower content of soluble calcium and phosphate ions. As a consequence, a longer period of MF operation, better whey clarification and lower calcium and phosphate content of the filtrate were achieved. This suggests that a loosely structured deposit was formed on the membrane surface which was less resistant to filtration than that resulting from the control pretreatment. During MF, it was necessary to avoid zones of high shear in the retentate compartment that might cause physical alteration of the aggregates.
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Dittrich, J., R. Gnirss, A. Peter-Fröhlich, and F. Sarfert. "Microfiltration of municipal wastewater for disinfection and advanced phosphorus removal." Water Science and Technology 34, no. 9 (November 1, 1996): 125–31. http://dx.doi.org/10.2166/wst.1996.0192.
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The objective of Research Project 02 WA 9253/4 on “Advanced Treatment of Municipal Wastewater: Microfiltration of municipal wastewater for disinfection and advanced phosphorus removal” which is supported by the BMBF (Federal Ministry for Education, Science, Research and Technology) is to show whether microfiltration (MF) is a technically feasible and economically competitive process for disinfection and phosphorus removal of secondary effluent. For bacteria and phosphorus removal, three different microfiltration systems (systems with flat sheet, tube and hollow-fibre modules) with a pore size of 0.2 μm are tested in small-scale pilot plants to find out whether they are suitable for municipal wastewater treatment. The most suitable system will afterwards be tested in one full-scale unit to obtain operational data. The monitoring program with the small-scale MF plants using the final effluent of the Berlin-Ruhleben wastewater treatment plant started in November 1993 and the results obtained so far can be summarized as follows. Total coliforms, E. coli, faecal streptococci and salmonella are removed to levels below the detection limit, less than 1 cfu/100 ml in the effluent of all three MF plants. Coliphage - as a surrogate organism for enterovirus - are significantly reduced with a 2-3 log removal, which means that the limit value for enterovirus laid down in the EU Bathing Water Directive can be met in the effluent of the MF plants. The average concentrations for total phosphorus (PT) in the effluent are 60 μg/l for the Memcor and the DOW units and 90 μg/l for the Starcosa unit without the use of precipitants. With a low ferric dosage of 0.014 mol/m3 prior to the MF, the average effluent PT concentrations of all three MF units are lower than the target concentration of 50 μg/l (no polymer feed). With a specific energy consumption of about 0.2 kWh/m3 filtrate the dead-end MF (Memcor) requires at least five times less energy than the cross-flow MF. Based on the energy consumption dead-end MF should be preferred if large volumetric flows of wastewater with a low concentration of solids have to be treated. Because of unfavourable energy consumption the tests with the cross-flow MF have been discontinued. When using MF systems in the final effluent of wastewater treatment plants, evidence must be produced in a full-scale MF unit to demonstrate that microfiltration is really suitable for practical application. This as well as a reliable calculation of investment and operating costs are the main objectives of further investigations within the framework of this research project.
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Tomczak, Wirginia, and Marek Gryta. "Cross-Flow Microfiltration of Glycerol Fermentation Broths with Citrobacter freundii." Membranes 10, no. 4 (April 8, 2020): 67. http://dx.doi.org/10.3390/membranes10040067.
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This paper reports the study of the cross-flow microfiltration (MF) of glycerol fermentation broths with Citrobacter freundii bacteria. A single channel tubular ceramic membrane with a nominal pore size of 0.14 µm was used. It has been demonstrated that the MF ceramic membrane has been successfully applied to bacteria cell removal and to effectively eliminate colloidal particles from glycerol fermentation broths. However, due to fouling, the significant reduction of the MF performance has been demonstrated. In order to investigate the impact of transmembrane pressure (TMP) and feed flow rate (Q) on MF performance, 24 experiments have been performed. The highest steady state permeate flux (138.97 dm3/m2h) was achieved for 0.12 MPa and 1000 dm3/h. Fouling analysis has been studied based on the resistance-in series model. It has been found that the percentage of irreversible fouling resistance during the MF increases with increasing TMP and Q. The permeate flux regeneration has been achieved by membrane cleaning with 3 wt % NaOH and 3 wt % H3PO4 at 45 °C. The results of this study are expected to be useful in industrially employing the MF process as the first step of glycerol fermentation broth purification.
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Qin, Wu, Yi Zhang, and Jianqing Wu. "Preparation of high-permeance ceramic microfiltration membranes using a pore-sealing method." RSC Advances 10, no. 10 (2020): 5560–65. http://dx.doi.org/10.1039/c9ra09805d.
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Furulyás, Diána, Fanni Savanya, Szilvia Bánvölgyi, Nóra Papp, Éva Stefanivots-Bányai, and Mónika Stéger-Máté. "Effects of Enzyme Treatment on the Microfiltration of Elderberry." Analecta Technica Szegedinensia 10, no. 1 (January 15, 2016): 40–46. http://dx.doi.org/10.14232/analecta.2016.1.40-46.
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The aim of this study was to evaluate the effect of microfiltration (MF) on the antioxidant capacity of elderberry juice using ceramic membrane. Previous to MF measurements preliminary examination was achieved with different enzymes. Four different samples were prepared: one without any enzyme and three with different pectolytic enzymes. The resistances were determined using the resistance-in-series model and difference between four enzyme-treated samples are evaluated. The effect of this technology on the antioxidant component of the clarified elderberry juice has been evaluated in permeate and retentate samples. For ferric reducing antioxidant power was measured with FRAP and total phenolic content (TPC) was determined with Folin Ciocalteau reagent. The total anthocyanin content (TAC) was estimated using spectrophotometric method. Higher juice yield was obtained using enzyme compared with enzyme-free elderberry pulp. The analytical results show that the MF membrane retained the valuable components in different rate. Significant losses are believed to have occurred after the MF clarification process due to fouling layer resistance, what can be decreased with pectolytic enzymes treatment.
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Yuasa, Akira. "Drinking water production by coagulation-microfiltration and adsorption-ultrafiltration." Water Science and Technology 37, no. 10 (May 1, 1998): 135–46. http://dx.doi.org/10.2166/wst.1998.0394.
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Microfiltration (MF) and ultrafiltration (UF) pilot plants were operated to produce drinking water from surface water from 1992 to 1996. Microfiltration was combined with pre-coagulation by polyaluminium chloride and was operated in a dead-end mode using hollow fiber polypropylene and monolith type ceramic membranes. Ultrafiltration pilot was operated in both cross-flow and dead-end modes using hollow fiber cellulose acetate membrane and was combined occasionally with powdered activated carbon (PAC) and granular activated carbon (GAC) adsorption. Turbidity in the raw water varied in the range between 1 and 100 mg/L (as standard Kaolin) and was removed almost completely in all MF and UF pilot plants to less than 0.1 mg/L. MF and UF removed metals such as iron, manganese and aluminium well. The background organics in the river water measured as KMnO4 demand varied in the range between 3 and 16 mg/L. KMnO4 demand decreased to less than 2 mg/L and to less than 3 mg/L on the average by the coagulation-MF process and the sole UF process, respectively. Combination of PAC or GAC adsorption with UF resulted in an increased removal of the background organics and the trihalomethanes formation potential as well as the micropollutants such as pesticides. Filtration flux was controlled in the range between 1.5 and 2.5 m/day with the trans-membrane pressure less than 100 kPa in most cases for MF and UF. The average water recovery varied from 99 to 85%.
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Komaladewi, Anak Agung Istri Agung Sri, Putu Teta Prihartini Aryanti, Graecia Lugito, I. Wayan Surata, and I. Gede Wenten. "Recent progress in microfiltration polypropylene membrane fabrication by stretching method." E3S Web of Conferences 67 (2018): 03018. http://dx.doi.org/10.1051/e3sconf/20186703018.
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Microfiltration polypropylene (MF-PP) membrane has been widely used in many industries due to their excellent combination of good separation performances and low production cost. In addition to membrane configuration, the structure of MF-PP membrane also plays an important role in separation performance. MF-PP membrane is commonly produced by thermal induced phase separation (TIPS) and stretching. TIPS is the simplest one where the polymer is dissolved in a solvent at a decent temperature and then cooled to induce phase separation which leads to the formation of microporous structure. However, this method is limited by the nature of PP that is difficult to dissolve in organic solvents and the solvent-contaminated effluent produced during the fabrication process. Therefore, the stretching method is more favorably used. The Stretching method involves four processing stages in sequence (i.e. melt-extrusion, annealing, stretching, and heat setting). Polymer composition, extrusion draw ratio, as well as stretching rate and temperature, are important parameters that significantly affect the pore structures evolved and thus the properties as well as the performances of MF-PP membrane. In this paper, the recent development of MF-PP fabrication by stretching methods as well as the parameters involved in each method will be reviewed and discussed comprehensively.
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Basu, Subhankar, Sangeeta Mukherjee, Ankita Kaushik, Vidya S. Batra, and Malini Balakrishnan. "Integrated treatment of molasses distillery wastewater using microfiltration (MF)." Journal of Environmental Management 158 (August 2015): 55–60. http://dx.doi.org/10.1016/j.jenvman.2015.04.037.
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Noor, M. J. M. M., S. A. Muyibi, T. Ahmed, A. H. Ghazali, A. Jusoh, A. Idris, F. R. Ahmadun, H. Nagaoka, and H. Aya. "Performance of an extended aeration - microfiltration (EAM) reactor in treating high strength industrial wastewater." Water Science and Technology 46, no. 9 (November 1, 2002): 331–38. http://dx.doi.org/10.2166/wst.2002.0272.
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A laboratory study was conducted on an Extended Aeration - Microfiltration (EAM) reactor in treating a food industry wastewater. The reactor contained horizontally laid hollow fibre microfiltration (MF) units that were fully submerged. The MF units were connected to a peristaltic pump that was used to extract permeate continuously under suction pressure. Continuous aeration from beneath the modules provided the crossflow effect to the MF units. Active activated sludge was used in the start-up where the sludge was mixed together with the feed water at a Food/Microorganisms (F/M) value of about 0.1. Primary effluent with Chemical Oxygen Demand (COD) values ranged between 1,500 and 3,000 mg/l was used as feed water. The EAM reactor was operated for nearly three months without initiating cleaning of the MF units. A suction pressure of 0.9 bar and Mixed Liquor Suspended Solids (MLSS) of over 5,500 mg/l were reached when nearing the end of the three month operation period. Permeate COD and turbidity reduction of over 97% and 99% respectively, were achieved. Prior to this, the MF module arrangements were studied; where vertically arranged modules were found to perform poorly as compared to the horizontally laid modules, in terms of clean water permeate flux.
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Kacprzyńska-Gołacka, Joanna, Anna Kowalik-Klimczak, Ewa Woskowicz, Piotr Wieciński, Monika Łożyńska, Sylwia Sowa, Wioletta Barszcz, and Bernadetta Kaźmierczak. "Microfiltration Membranes Modified with Silver Oxide by Plasma Treatment." Membranes 10, no. 6 (June 26, 2020): 133. http://dx.doi.org/10.3390/membranes10060133.
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Microfiltration (MF) membranes have been widely used for the separation and concentration of various components in food processing, biotechnology and wastewater treatment. The deposition of components from the feed solution and accumulation of bacteria on the surface and in the membrane matrix greatly reduce the effectiveness of MF. This is due to a decrease in the separation efficiency of the membrane, which contributes to a significant increase in operating costs and the cost of exploitative parts. In recent years, significant interest has arisen in the field of membrane modifications to make their surfaces resistant to the deposition of components from the feed solution and the accumulation of bacteria. The aim of this work was to develop appropriate process parameters for the plasma surface deposition of silver oxide (AgO) on MF polyamide membranes, which enables the fabrication of filtration materials with high permeability and antibacterial properties.
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Yeh, H. H., and W. H. Wang. "A study on the fouling phenomena of a microfiltration membrane." Water Supply 4, no. 5-6 (December 1, 2004): 223–31. http://dx.doi.org/10.2166/ws.2004.0112.
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The utilization of membrane processes for drinking water treatment has become more popular. However, fouling by source water probably is the major factor prohibits its widespread application. In this research, the fouling phenomena of a microfiltration (MF) membrane were studied. The interactions among colloidal particles, calcium ion, and dissolved organics, such as salicylic acid, humic acid, and alginic acid, on MF fouling were focused. A lab-scale single hollow fiber MF membrane, made of polyvinylidenefluoride (PVDF), module was used. The results show that, for single organic compound, the extent of fouling caused by humic acid was higher that of alginic acid. For the latter, the permeate flux decrease at lower pH was more significant than those at higher pH. For low MW salicylic acid, both rejection and flux decrease were minor. It seems that solubility have strong correlation with fouling rate. The higher the solubility is, the lower the fouling rate. For sole colloidal particle system, latex beads with diameter close to the pore size of MF membrane showed severe fouling. Adding Ca can aggregate the latex beads, and alleviate fouling. However, calcium ion also found to increase fouling of alginic acid on membrane under neutral or alkali pH condition, probably via charge neutralization and/or bridging. In conclusion, MF fouling seems to be strongly related to the type of organics, size of colloidal particles, and the existence of divalent ions, in the feed water.
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Hashino, M., Y. Mori, Y. Fujii, N. Motoyama, N. Kadokawa, H. Hoshikawa, W. Nishijima, and M. Okada. "Pilot plant evaluation of an ozone-microfiltration system for drinking water treatment." Water Science and Technology 41, no. 10-11 (May 1, 2000): 17–23. http://dx.doi.org/10.2166/wst.2000.0598.
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We have developed a novel ozone resistant microfiltration (MF) module using an organic hollow fiber membrane made of polyvinylidenefluoride (PVDF). A new filtration system using this MF module together with ozone dose provided three to four times higher permeate flux compared with the filtration without ozone. The reaction of ozone with organic materials in feed water was necessary to occur on the surface of the membrane to have higher permeate flux.
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Le, Sowe, Chen, Duong, Ray, and Nguyen. "Exploring Nanosilver-Coated Hollow Fiber Microfiltration to Mitigate Biofouling for High Loading Membrane Bioreactor." Molecules 24, no. 12 (June 25, 2019): 2345. http://dx.doi.org/10.3390/molecules24122345.
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For the first time, a nanosilver-coated hollow fiber microfiltration (MF) was fabricated by a simple chemical reduction method, then tested for membrane biofouling mitigation study under extreme high mixed liquor suspended solid (MLSS) concentration for long term. This study presents a simple and novel technique to modify a commercially available MF membrane using silver nanoparticles (AgNPs) followed by an investigation of mitigating membrane biofouling potentials using this modified membrane to compare with an unmodified membrane for 60-day operation period. The modified membranes showed that AgNPs was attached to the MF-membrane successfully with a high density of 119.85 ± 5.42 mg/m2. After long-term testing of 60 days in membrane bioreactor with a MLSS concentration of 11,000 mg/L, specific flux of the AgNPs coated MF (AgNPs-MF) decreased 59.7%, while the specific flux of the unmodified membrane dropped 81.8%, resulted from the increase of transmembrane vacuum pressure for the AgNPs-MF was lower than that of the unmodified one. The resistance-in-series model was used to calculate the resistance coefficients of membrane modules, and the result showed that the cake layer resistance coefficient of the unmodified membrane was 2.7 times higher than that of the AgNPs-MF after the 60-day operation, confirming that AgNPs displayed great antimicrobial properties to mitigate membrane biofouling under such high MLSS.
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Nguyen, S. T., F. A. Roddick, and J. L. Harris. "Membrane foulants and fouling mechanisms in microfiltration and ultrafiltration of an activated sludge effluent." Water Science and Technology 62, no. 9 (November 1, 2010): 1975–83. http://dx.doi.org/10.2166/wst.2010.505.
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Membrane fouling in microfiltration (MF) and ultrafiltration (UF) of an activated sludge (AS) effluent was investigated. It was found that the major membrane foulants were polysaccharides, proteins, polysaccharide-like and protein-like materials and humic substances. MF fouling by the raw effluent was governed by pore adsorption of particles smaller than the pores during the first 30 minutes of filtration and then followed the cake filtration model. UF fouling could be described by the cake filtration model throughout the course of filtration. Coagulation with alum and (poly)aluminium chlorohydrate (ACH) altered the MF fouling mechanism to follow the cake filtration model from the beginning of filtration. The MF and UF flux improvement by coagulation was due to the removal of some of the foulants in the raw AS effluent by the coagulants. The MF flux improvement was greater for alum than for ACH whereas the two coagulants performed equally well in UF. Coagulation also reduced hydraulically irreversible fouling on the membranes and this effect was more prominent in MF than in UF. The unified membrane fouling index (UMFI) was used to quantitatively evaluate the effectiveness of coagulation on membrane flux enhancement.
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Yu, Xiaoli, Zhaoxiang Zhong, and Weihong Xing. "Treatment of vegetable oily wastewater using an integrated microfiltration–reverse osmosis system." Water Science and Technology 61, no. 2 (January 1, 2010): 455–62. http://dx.doi.org/10.2166/wst.2010.822.
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Vegetable oil processing plants and catering trade often generate a large amount of oil-containing wastewater, which causes serious environmental problems. The objective of this work was to explore the feasibility of vegetable oil wastewater treatment with an integrated microfiltration–reverse osmosis (MF–RO) process. The influence of operational parameters on the separation behaviors were investigated in MF process. In MF continuous process the steady flux was around 90 (L/m2 h) when the concentrated multiple reached 16, and the oil content in permeate was less than 12 mg/L. In the RO continuous process, antifouling membrane was used to treat permeate from the ceramic membrane process in order to improve the water quality. The RO process had a permeate flux of 24 (L/m2 h) and water recovery rate of 95%. The permeate from the RO stage was free of oil, and its TOC and conductivity were less than 0.6 mg/L and 50 μs/cm, respectively. The results demonstrated that the two stage membrane process combining MF and RO is highly efficient in the treatment of oil-containg wastewater.
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Fan, Kai, Guoqing Zhou, Jinjin Zhang, Haijun Yang, Jun Hu, and Zhengchi Hou. "pH-sensitive microfiltration membrane prepared from polyethersulfone grafted with poly(itaconic acid) synthesized by simultaneous irradiation in homogeneous phase." Water Science and Technology 78, no. 3 (August 1, 2018): 602–10. http://dx.doi.org/10.2166/wst.2018.330.
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Abstract Poly(itaconic acid) (PIA) was grafted onto polyethersulfone (PES) by homogeneously phased γ-ray irradiation. Kinetic polymerization observed was studied by analyzing the effect of irradiation dosages and monomer concentrations. Then, a pH-sensitive microfiltration (MF) membrane was prepared from these PES-g-PIA polymers with different degrees of grafting under phase inversion method. Finally, the contact angles, morphologies, pore sizes, deionized water permeability and filtration performance for aqueous polyethylene glycols solution of the MF membranes were studied. The results show that grafting PIA groups onto PES molecular chains endowed the MF membranes with effective pH-sensitive properties.
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Matsui, Y., T. Sanogawa, N. Aoki, S. Mima, and T. Matsushita. "Evaluating submicron-sized activated carbon adsorption for microfiltration pretreatment." Water Supply 6, no. 1 (January 1, 2006): 149–55. http://dx.doi.org/10.2166/ws.2006.017.
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Submicron powdered activated carbon (PAC) rapidly adsorbed natural organic matter (NOM) fromwater samples: a batch test of the adsorption kinetics showed that the NOM concentration dropped substantially within 15 s and then leveled off. In a tubular flow reactor test, NOM removal after a 15 s contact time was almost the same as removal values attained at longer contact times. Laboratory-scale and bench-scale pilotplant ceramic microfiltration (MF) experiments with submicron PAC adsorption pretreatment were conducted to evaluate NOM removal and to examine the effect of the PAC on filterability. The laboratory scale MF experiment revealed that PAC adsorption pretreatment could be accomplished with a detention (2.4 s) that was much shorter than the time expected from the adsorption kinetics test. This result suggests that adsorption pretreatment for MF could be accomplished by adding the submicron PAC directly into the feed line to the membrane and that installation of a special PAC contactor before the membrane unit is unnecessary. Although micron PAC rather than submicron PAC was used unintentionally in the pilot plant experiment, these PAC showed much better NOM removal than normal PAC, and no adverse effects, such as transmembrane pressure buildup and reversible or irreversible membrane fouling, were observed.
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Kim, S. H., J. S. Yoon, and C. H. Yoon. "Evaluation of microfiltration system performance as pre-treatment for reverse osmosis seawater desalination through pilot-plant operation." Water Supply 6, no. 4 (October 1, 2006): 163–69. http://dx.doi.org/10.2166/ws.2006.746.
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This study was undertaken to evaluate the suitability of microfiltration (MF) as pre-treatment for reverse osmosis (RO) seawater desalination to treat the seawater suffering from red-tide contamination using long-term operation of pilot plant. The one and a half year pilot MF operation had two objectives: stable production of the flow rate of 5 m3/h and acceptable water quality (SDI less than 3). The pilot plant operation revealed that the MF system successfully produced the target flow rate despite red-tide contamination of the seawater. The average flow rate of 5.2 m3/h was obtained at the average operating pressure of 0.53 bar. However, the MF system failed to achieve the target flow rate at red-tide bloom. When red-tide bloom occurred the chlorophyll-a concentration became 136 mg/m3, the flow rate decreased to half of the target, and energy consumption became extremely high. Subsequently, the operation was stopped. According to the relationship between the flow rate of the MF system and chlorophyll-a concentration developed in this study, it would be desirable to stop the MF operation at chlorophyll-a concentration of 57 mg/m3. The MF system produced acceptable quality water for RO feeding. The SDI of the MF treated was consistently less than 3. The MF system consumed 0.5 KWh of energy to produce 1 m3/h of MF treated, if the data during the red-tide bloom were excluded. Extra equipment (intake pump, control system, monitoring system, air conditioner) caused higher energy consumption than expected.
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Hirata, T., and A. Hashimoto. "Experimental assessment of the efficacy of microfiltration and ultrafiltration for Cryptosporidium removal." Water Science and Technology 38, no. 12 (December 1, 1998): 103–7. http://dx.doi.org/10.2166/wst.1998.0515.
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In order to evaluate the efficacy of microfiltration and ultrafiltration for Cryptosporidium oocyst removal, a bench-scale experiment was carried out using two 0.2m2 molecules, MF (nominal pore size 0.25μm) and UF (nominal cut-off MW 13,000 daltons) in cross-flow mode at an oocyst level of 106/L. Both of the membranes eliminated the oocysts from the influents with removal efficiency estimated to be >7 log10. As for the MF, an additional experiment was conducted at a much higher oocyst level up to 108 oocysts/L in both cross-flow and dead-end modes and which achieved >7 log10 removal, although some oocysts appeared in the filtrate in both modes. Based on these results, microfiltration and ultrafiltration are conclusively considered to be excellent processes for drinking water treatment as a single process that produces safe (an annual risk 10−4) water from highly polluted source waters.
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Hong, S. K., F. A. Miller, and J. S. Taylor. "Assessing pathogen removal efficiency of microfiltration by monitoring membrane integrity." Water Supply 1, no. 4 (June 1, 2001): 43–48. http://dx.doi.org/10.2166/ws.2001.0065.
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This study was conducted to investigate the ability of various methods of monitoring membrane integrity to respond to changes in actual membrane integrity imposed by the compromised fibers within the microfiltration unit. In addition, the pilot-scale MF unit was challenged with high concentrations of coliform, Cryptosporidium, and spore, in order to assess the pathogen removal capability of microfiltration. A correlation between the integrity tests and microbial challenge data was also made. The integrity tests investigated in this study were pressure decay and diffusive air flow tests (direct integrity tests), and turbidity and particle counting (indirect integrity tests). Both pressure decay (PDT) and diffusive air flow (DAF) tests were sensitive enough to detect one damaged fiber out of 66,000. The extent of fouling did not affect the sensitivity of the PDT and DAF, showing that PDT and DAF tests are a simple, reliable means to monitor membrane integrity under field conditions. Indirect integrity monitoring using turbidity and particle counting, however, responded poorly to changes in membrane integrity. Microbial challenge study demonstrated that microfiltration was capable of removing various pathogens including Cryptosporidium, at the level required by drinking water regulations, under even adverse operating conditions. Finally, PDT and DAF tests showed a better correlation with actual microbial removal efficiency of microfiltration than turbidity and particle counting. The turbidity and particle counting grossly underestimated the removal of pathogen larger than MF membrane pore size due to poor sensitivity.
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Song, Ya Li, Bing Zhi Dong, Nai Yun Gao, Yu Fang Yang, and Chun Chang. "Application of a Hybrid Process Combining Ozone-Coagulation-Microfiltration for Drinking Water Production." Applied Mechanics and Materials 212-213 (October 2012): 600–604. http://dx.doi.org/10.4028/www.scientific.net/amm.212-213.600.
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The study concerns on drinking water treatment with combining ozonation process, coagulation and Microfiltration (MF) of Poly-vinylidene Fluoride (PVDF) in a dead-end filtration. The pilot-scale process consists of several parts: pre-ozonation, coagulation, sedimentation and microfiltration membrane separation. Ozone of 0.5mg/l and alum of 10 mg/l were added into raw water. The experience focuses on investigation of permeate water quality and variation of trans-membrane pressure (TMP). The results of the study showed that good permeate quality were fulfilled. Turbidity of permeate was consistently below 0.1 NTU. The MF membrane removed iron perfectly, which was below 0.3 mg/l. The reduction of manganese and CODMn met the China Drinking Water Regulations. Additionally, TMP was stable during filtration for a long time and ozone could delay membrane fouling. Chemical cleaning of membrane could decrease TMP to initial level, and chemical analysis for chemical cleaning solution shown that organic matters and manganese caused membrane fouling.
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Campinas, Margarida, Rui M. C. Viegas, Rosário Coelho, Helena Lucas, and Maria João Rosa. "Adsorption/Coagulation/Ceramic Microfiltration for Treating Challenging Waters for Drinking Water Production." Membranes 11, no. 2 (January 27, 2021): 91. http://dx.doi.org/10.3390/membranes11020091.
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Pressurized powdered activated carbon/coagulation/ceramic microfiltration (PAC/Alum/MF) was investigated at pilot scale for treating low turbidity and low natural organic matter (NOM) surface waters spiked with organic microcontaminants. A total of 11 trials with clarified or non-clarified waters spiked with pesticides, pharmaceutical compounds, or microcystins were conducted to assess the removal of microcontaminants, NOM (as 254 nm absorbance, A254, and dissolved organic carbon, DOC), trihalomethane formation potential (THMFP), aerobic endospores as protozoan (oo)cysts indicators, bacteriophages as viruses indicators, and regular drinking water quality parameters. PAC/(Alum)/MF achieved 75% to complete removal of total microcontaminants with 4–18 mg/L of a mesoporous PAC and 2 h contact time, with a reliable particle separation (turbidity < 0.03 NTU) and low aluminium residuals. Microcontaminants showed different amenabilities to PAC adsorption, depending on their charge, hydrophobicity (Log Kow), polar surface area and aromatic rings count. Compounds less amenable to adsorption showed higher vulnerability to NOM competition (higher A254 waters), greatly benefiting from DOC-normalized PAC dose increase. PAC/Alum/MF also attained 29–47% NOM median removal, decreasing THMFP by 26%. PAC complemented NOM removal by coagulation (+15–19%), though with no substantial improvement towards THMFP and membrane fouling. Furthermore, PAC/Alum/MF was a full barrier against aerobic endospores, and PAC dosing was crucial for ≥1.1-log reduction in bacteriophages.
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Matsui, Y., R. Murase, T. Sanogawa, N. Aoki, S. Mima, T. Inoue, and T. Matsushita. "Rapid adsorption pretreatment with submicrometre powdered activated carbon particles before microfiltration." Water Science and Technology 51, no. 6-7 (March 1, 2005): 249–56. http://dx.doi.org/10.2166/wst.2005.0644.
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Manufacturer-supplied powdered activated carbon (PAC) was ground to produce submicrometre particles (0.8 and 0.6 μm median diameter) for use as an adsorbent before microfiltration (MF) for drinking water treatment. Batch tests revealed that the microground PAC adsorbed natural organic matter (NOM) much more rapidly and had a higher adsorptive capacity than ordinary PAC. The water samples pretreated with the submicrometre PAC were subjected to MF, and the results of experiments with different PAC contact times revealed that a 1 min retention time was sufficient for adsorptive removal of NOM. The use of submicrometre PAC permitted not only shorter PAC contact times but also a 75% reduction in dose.
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Tupasela, Tuomo, Heikki Koskinen, and Pirkko Antila. "Whey pretreatments before ultrafiltration." Agricultural and Food Science 3, no. 5 (September 1, 1994): 473–79. http://dx.doi.org/10.23986/afsci.72719.
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Whey is a by-product of cheesemaking. Whey dry matter contains mainly lactose, but also valuable whey proteins. The aim of this study was to develop improvements to whey protein membrane isolation processes. In our trials CaCl2 -added, pH-adjusted and heat-treated wheys were found to have MF (microfiltration) permeate fluxes about 30% higher than in untreated MF whey. The total solids and protein content of the MF permeates decreased compared to the original wheys. UF (ultrafiltration) trials were conducted using MF whey to compare it with centrifugally separated whey. The MF whey consistently maintained an UF flux about 1.5 to 2.5 times higher than that of the separated whey. Differently treated MF whey UF permeate fluxes also showed a difference. With CaCl2 addition, pH adjustment and heat treatment, the UF permeate fluxes were about 20 to 40% higher than when only MF was used. The total solids content decreased in each trial. The protein content of the UF concentrate also decreased compared to the MF permeate. The (β-lg (β-lactoglobulin) and α-la (α-lactalbumin) content was almost the same in UF concentrates as in MF permeates.
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Jung, Jong Tae, Jong Oh Kim, and Won Youl Choi. "Performance of Photocatalytic Microfiltration with Hollow Fiber Membrane." Materials Science Forum 544-545 (May 2007): 95–98. http://dx.doi.org/10.4028/www.scientific.net/msf.544-545.95.
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The purpose of this study is to investigate the effect of the operational parameters of the UV intensity and TiO2 dosage for the removal of humic acid and heavy metals. It also evaluated the applicability of hollow fiber microfiltration for the separation of TiO2 particles in photocatalytic microfiltration systems. TiO2 powder P-25 Degussa and hollow fiber microfiltration with a 0.4 μm nominal pore size were used for experiments. Under the conditions of pH 7 and a TiO2 dosage 0.3 g/L, the reaction rate constant (k) for humic acid and heavy metals increased with an increase of the UV intensity in each process. For the UV/TiO2/MF process, the reaction rate constant (k) for humic acid and Cu, with the exception of Cr in a low range of UV intensity, was higher compared to that of UV/TiO2 due to the adsorption of the membrane surface. The reaction rate constant (k) increased as the TiO2 dosage increased in the range of 0.1~0.3 g/L. However it decreased for a concentration over 0.3 g/L of TiO2. For the UV/TiO2/MF process, TiO2 particles could be effectively separated from treated water via membrane rejection. The average removal efficiency for humic acid and heavy metals during the operational time was over 90 %. Therefore, photocatalysis with a membrane is believed to be a viable process for humic acid and heavy metals removal.
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Hakami, Mohammed Wali, Abdullah Alkhudhiri, Sirhan Al-Batty, Myrto-Panagiota Zacharof, Jon Maddy, and Nidal Hilal. "Ceramic Microfiltration Membranes in Wastewater Treatment: Filtration Behavior, Fouling and Prevention." Membranes 10, no. 9 (September 22, 2020): 248. http://dx.doi.org/10.3390/membranes10090248.
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Nowadays, integrated microfiltration (MF) membrane systems treatment is becoming widely popular due to its feasibility, process reliability, commercial availability, modularity, relative insensitivity in case of wastewater of various industrial sources as well as raw water treatment and lower operating costs. The well thought out, designed and implemented use of membranes can decrease capital cost, reduce chemical usage, and require little maintenance. Due to their resistance to extreme operating conditions and cleaning protocols, ceramic MF membranes are gradually becoming more employed in the drinking water and wastewater treatment industries when compared with organic and polymeric membranes. Regardless of their many advantages, during continuous operation these membranes are susceptible to a fouling process that can be detrimental for successful and continuous plant operations. Chemical and microbial agents including suspended particles, organic matter particulates, microorganisms and heavy metals mainly contribute to fouling, a complex multifactorial phenomenon. Several strategies, such as chemical cleaning protocols, turbulence promoters and backwashing with air or liquids are currently used in the industry, mainly focusing around early prevention and treatment, so that the separation efficiency of MF membranes will not decrease over time. Other strategies include combining coagulation with either inorganic or organic coagulants, with membrane treatment which can potentially enhance pollutants retention and reduce membrane fouling.
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Bouzerara, Ferhat, Souad Boulanacer, and Abdelhamid Harabi. "Shaping of microfiltration (MF) ZrO2 membranes using a centrifugal casting method." Ceramics International 41, no. 3 (April 2015): 5159–63. http://dx.doi.org/10.1016/j.ceramint.2014.11.141.
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Choo, K. H., I. H. Park, and S. J. Choi. "Removal of natural organic matter using iron oxide-coated membrane systems." Water Supply 4, no. 5-6 (December 1, 2004): 207–13. http://dx.doi.org/10.2166/ws.2004.0110.
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Natural organic matter (NOM) removal and membrane fouling were investigated using iron oxide-coated microfiltration (MF) systems for drinking water treatment. Addition of iron oxide particle (IOP) adsorbents into MF always improved NOM removal and reduced fouling, but IOP dosing methods did affect the membrane performance. The IOP coating layer formed on the membrane surface played a major role in preventing membrane fouling by residual NOM in water. Pre-mixing of IOP with raw water followed by continuous injection into the MF system controlled membrane fouling better than pre- and intermittent loadings of IOP. This could be in close association with the distribution of IOPs across the hollow fiber MF surfaces and the effectiveness of contact of IOP with feedwater. The turbidity of water influenced the MF system with intermittent IOP loads more greatly than that with IOP in suspension. There existed an optimal IOP dose where membrane fouling can be minimized achieving maximal NOM removal.
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Dang, H. T. T., H. D. Tran, S. H. Tran, M. Sasakawa, and R. M. Narbaitz. "Treatment and reuse of coalmine wastewater in Vietnam: application of microfiltration." Water Quality Research Journal 53, no. 3 (April 30, 2018): 133–42. http://dx.doi.org/10.2166/wqrj.2018.028.
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Abstract Due to stringent local regulations and adverse environmental impacts, Vietnamese coal mining industries are under pressure to reuse the large volume of wastewater they produce. To this end, the aim of this study was to add microfiltration (MF) membranes after the conventional Vietnamese coalmine wastewater treatment systems (coagulation/sedimentation/filtration) to assess the feasibility of effluent reuse. The pilot-scale test was performed at a coalmine plant located in Quang Ninh province, Vietnam. Results indicate that precipitation with slaked lime (Ca(OH)2) and polyaluminum chloride (PACl) followed by sand filtration are important pre-treatment steps, prior to microfiltration. To achieve high Mn removals the sand in the filter had to be replaced by a KMnO4 coated sand. The MF membrane produced a stable and high quality effluent that meets the Vietnamese National Technical Regulations for Drinking Water quality (Fe < 0.5 mg/L, Mn < 0.3 mg/L, hardness <350 mg/L as CaCO3). Complete membrane recovery was achieved by sequential 24 h soakings in NaOCl, citric acid and a surfactant.
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Chang, C. Y., C. C. Wang, D. J. Chang, and J. S. Chang. "Combined Fenton-MF process increases acrylonitrile removal." Water Science and Technology 47, no. 9 (May 1, 2003): 179–84. http://dx.doi.org/10.2166/wst.2003.0520.
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The Fenton oxidation process is possessed of the advantages of both oxidation and coagulation processes. In addition to these functions, Fenton's reagent is also a typical initiator of polymerization. The application of the Fenton-microfiltration process for removal of acrylonitrile (AN), which is the major raw material for manufacturing ABS resins, was investigated. As for Fenton oxidation, in the range of pH 2 to pH 4, AN removal efficiency increased as the pH increased. In experiments of the same initial molar ratio of [FeSO4]0/[H2O2]0, the higher dosage can obtain the higher removal efficiency. At pH 4, the AN removal increased as the [H2O2]0 increased for each [FeSO4]0. Acrylic acid and acrylamide were detected in the solution after Fenton oxidation. On the other hand, acrylamide, polyacrylamide, and polyacrylic acid exist in the precipitate after the Fenton oxidation of AN solution. Moreover, It was also found that the operational mode is an important factor of the combined Fenton-MF process.
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Granger-Delacroix, Manon, Nadine Leconte, Fabienne Garnier-Lambrouin, Françoise Le Goff, Marieke Van Audenhaege, and Geneviève Gésan-Guiziou. "Transmembrane Pressure and Recovery of Serum Proteins during Microfiltration of Skimmed Milk Subjected to Different Storage and Treatment Conditions." Foods 9, no. 4 (March 27, 2020): 390. http://dx.doi.org/10.3390/foods9040390.
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Milk pre-processing steps-storage at 4 °C (with durations of 48, 72 or 96 h) and methods for microbiological stabilization of milk (1.4 μm microfiltration, thermization, thermization + bactofugation, pasteurization) are performed industrially before 0.1 µm-microfiltration (MF) of skimmed milk to ensure the microbiological quality of final fractions. The objective of this study was to better understand the influence of these pre-processing steps and their cumulative effects on MF performances (i.e., transmembrane pressure, and transmission and recovery of serum proteins (SP) in the permeate). Results showed that heat treatment of skimmed milk decreased ceramic MF performances, especially after a long 4 °C storage duration (96 h) of raw milk: when milk was heat treated by pasteurization after 96 h of storage at 4 °C, the transmembrane pressure increased by 25% over a MF run of 330 min with a permeation flux of 75 L·h−1·m−2 and a volume reduction ratio of 3.0. After 48 h of storage at 4 °C, all other operating conditions being similar, the transmembrane pressure increased by only 6%. When milk was 1.4 µm microfiltered, the transmembrane pressure also increased by only 6%, regardless of the duration of 4 °C storage. The choice of microbiological stabilization method also influenced SP transmission and recovery: the higher the initial heat treatment of milk, the lower the transmission of SP and the lower their recovery in permeate. Moreover, the decline of SP transmission was all the higher that 4 °C storage of raw milk was long. These results were explained by MF membrane fouling, which depends on the load of microorganisms in the skimmed milks to be microfiltered as well as the rate of SP denaturation and/or aggregation resulting from pre-processing steps.
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Ring, E., M. Samblebe, M. Leak, and S. Gray. "NOM removal for extension of chlorine dioxide residuals and lower biological regrowth potentials." Water Supply 4, no. 4 (December 1, 2004): 251–54. http://dx.doi.org/10.2166/ws.2004.0085.
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Techniques to decrease the rate of chlorine dioxide (ClO2) decay in a treated water from Whitfield, Australia were investigated. Biofiltration, microfiltration (MF) and ultrafiltration (UF) were considered as possible means of removing organic compounds which react with the ClO2. Membrane filtration removed more organic material than biofiltration, but biofiltration led to greater ClO2 durations and lower biological regrowth potentials than MF or UF. The results indicated that biofiltration was able to preferentially remove the fast reacting component of organic material that led to rapid ClO2 decay and also lowered the biological regrowth potential of the water.
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Shirasaki, N., T. Matsushita, Y. Matsui, K. Ohno, and M. Kobuke. "Virus removal in a hybrid coagulation–microfiltration system–Investigating mechanisms of virus removal by a combination of PCR and PFU methods." Water Supply 7, no. 5-6 (December 1, 2007): 1–8. http://dx.doi.org/10.2166/ws.2007.136.
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Virus removal performance and mechanisms were investigated in a hybrid coagulation–microfiltration (MF) system by using river water spiked with bacteriophage Qβ. Virus removal increased with filtration time: the rate of virus removal was 4 log at the beginning of filtration and gradually increased to 6 log over 5 h, probably because of the growth of a cake layer that accumulated on the membrane surface. Quantification of the virus particles in the MF compartment by a combination of a polymerase chain reaction (PCR) method and a plaque forming unit (PFU) method revealed that most of the virus (>99.999%) in the MF compartment was entrapped in the aluminium floc and then located in the solid phase; most of the virus (>99.9%) in the solid phase was inactivated. The rate of recovery of virus particles from the MF compartment decreased with filtration time: after 3 h of filtration approximately half of the virus particles in the MF compartment were not recovered by hydraulic backwashing, indicating that the virus might have been retained on the MF membrane as part of an irreversible foulant.
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Rasouli, Yaser, Mohsen Abbasi, and Seyed Abdollatif Hashemifard. "Oily wastewater treatment by adsorption–membrane filtration hybrid process using powdered activated carbon, natural zeolite powder and low cost ceramic membranes." Water Science and Technology 76, no. 4 (May 20, 2017): 895–908. http://dx.doi.org/10.2166/wst.2017.247.
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In this research, four types of low cost and high performance ceramic microfiltration (MF) membranes have been employed in an in-line adsorption–MF process for oily wastewater treatment. Mullite, mullite-alumina, mullite-alumina-zeolite and mullite-zeolite membranes were fabricated as ceramic MF membranes by low cost kaolin clay, natural zeolite and α-alumina powder. Powdered activated carbon (PAC) and natural zeolite powder in concentrations of 100–800 mg L−1 were used as adsorbent agent in the in-line adsorption–MF process. Performance of the hybrid adsorption–MF process for each concentration of PAC and natural zeolite powder was investigated by comparing quantity of permeation flux (PF) and total organic carbon (TOC) rejection during oily wastewater treatment. Results showed that by application of 400 mg L−1 PAC in the adsorption–MF process with mullite and mullite-alumina membranes, TOC rejection was enhanced up to 99.5% in comparison to the MF only process. An increasing trend was observed in PF by application of 100–800 mg L−1 PAC. Also, results demonstrated that the adsorption–MF process with natural zeolite powder has higher performance in comparison to the MF process for all membranes except mullite-alumina membranes in terms of PF. In fact, significant enhancement of PF and TOC rejection up to 99.9% were achieved by employing natural zeolite powder in the in-line adsorption–MF hybrid process.
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Chamberland, Julien, Dany Mercier-Bouchard, Iris Dussault-Chouinard, Scott Benoit, Alain Doyen, Michel Britten, and Yves Pouliot. "On the Use of Ultrafiltration or Microfiltration Polymeric Spiral-Wound Membranes for Cheesemilk Standardization: Impact on Process Efficiency." Foods 8, no. 6 (June 8, 2019): 198. http://dx.doi.org/10.3390/foods8060198.
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Ultrafiltration (UF) and microfiltration (MF) are widely-used technologies to standardize the protein content of cheesemilk. Our previous work demonstrated that protein retention of a 0.1-µm MF spiral-wound membrane (SWM) was lower, but close to that of a 10 kDa UF one. Considering that the permeability of MF membranes is expected to be higher than that of UF ones, it was hypothesized that the former could improve the efficiency of the cheesemaking process. Consequently, the objectives of this work were to compare 0.1-µm MF and 10 kDa UF spiral-wound membranes in terms of (1) hydraulic and separation performance, (2) energy consumption and fouling behavior, (3) cheesemaking efficiency of retentates enriched with cream, and (4) economic performance in virtual cheesemaking plants. This study confirmed the benefits of using MF spiral-wound membranes to reduce the specific energy consumption of the filtration process (lower hydraulic resistance and higher membrane permeability) and to enhance the technological performance of the cheesemaking process (higher vat yield, and protein and fat recoveries). However, considering the higher serum protein retention of the UF membrane and the low price of electricity in Canada, the UF scenario remained more profitable. It only becomes more efficient to substitute the 10 kDa UF SWM by the 0.1-μm MF when energy costs are substantially higher.
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Song, H., X. Fan, Y. Zhang, T. Wang, and Y. Feng. "Application of microfiltration for reuse of backwash water in a conventional water treatment plant - a case study." Water Supply 1, no. 5-6 (June 1, 2001): 199–206. http://dx.doi.org/10.2166/ws.2001.0115.
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In conventional drinking water treatment processes, the amount of the filter backwash water covers nearly 3% of the total production. To reduce the water loss and waste discharge in the conventional drinking water treatment process, the Macao Water Supply Co. Ltd (SAAM) plans to recover the backwash water by Microfiltration (MF) membrane process as water resources are scarce and new environmental regulations are mandated in Macao. Generally, the filter backwash water from the conventional water treatment plant with sedimentation process is recycled to the source water to be treated again under certain conditions, and the sedimentation tank discharges most of the sludge. However, it is possible to recycle the backwash water directly to the inlet for direct filtration process due to the limitation of inlet turbidity. This paper describes how to apply MF technology to treat the backwash water of the direct filtration plant and to optimize MF operation. Without pre-treatment of the settling basin for backwash water, the operation of the MF pilot plant is proved to be stable and the permeate quality can meet EU drinking water standards. The pilot study shows that it is both economically and technically feasible to adopt MF technology in backwash water treatment. The main parameters to test MF process include flux, chemical cleaning duration and transmembrane pressure (TMP). They are 150-200 L/m2.h, 20 days and <1 bar respectively. The estimated cost including O&M and investment for a 1320-1760 m3/d backwash water treatment plant is USD 0.126-0.168/m3.
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Rukapan, Weerapong, Benyapa Khananthai, Thirdpong Srisukphun, Wilai Chiemchaisri, and Chart Chiemchaisri. "Comparison of reverse osmosis membrane fouling characteristics in full-scale leachate treatment systems with chemical coagulation and microfiltration pre-treatments." Water Science and Technology 71, no. 4 (November 19, 2014): 580–87. http://dx.doi.org/10.2166/wst.2014.468.
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Fouling characteristics of reverse osmosis (RO) membrane with chemical coagulation and microfiltration (MF) pre-treatment were investigated at full-scale leachate treatment systems. In chemical coagulation pre-treatment, solid separation from stabilized leachate was performed by ferric chloride coagulation followed by sand filtration. Meanwhile, MF pre-treatment and the RO system utilized direct filtration using a 0.03 µm membrane without chemical addition. MF pre-treatment yielded better pollutant removals in terms of organics and nitrogen. The study on effect of pre-treatment on RO membrane fouling revealed that accumulated foulant on the RO membrane in MF pre-treatment was significantly lower than that of chemical coagulation. Nevertheless, NaOH cleaning of the fouled RO membrane after chemical coagulation pre-treatment could better recover its permeate flux, thus suggesting that the formation of a loose-structure cake layer by chemical coagulation pre-treatment could allow effective penetration of chemical cleaning and detachment of foulant layer from the membrane surface.
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Tomczak, Wirginia, and Marek Gryta. "Application of Capillary Polypropylene Membranes for Microfiltration of Oily Wastewaters: Experiments and Modeling." Fibers 9, no. 6 (June 2, 2021): 35. http://dx.doi.org/10.3390/fib9060035.
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Oily wastewaters are considered as one of the most dangerous types of environmental pollution. In the present study, the microfiltration (MF) process of model emulsions and real oily wastewaters was investigated. For this purpose, capillary polypropylene (PP) membranes were used. The experiments were conducted under transmembrane pressure (TMP) and feed flow rate (VF) equal to 0.05 MPa and 0.5 m/s, respectively. It was found that the used membranes ensured a high-quality permeate with turbidity equal to about 0.4 NTU and oil concentration of 7–15 mg/L. As expected, a significant decrease in the MF process performance was noted. However, it is shown that the initial decline of permeate flux could be slightly increased by increasing the feed temperature from 25 °C to 50 °C. Furthermore, Hermia’s models were used to interpret the fouling phenomenon occurring in studied experiments. It was determined that cake formation was the dominant fouling mechanism during filtration of both synthetic and real feeds. Through detailed studies, we present different efficient methods of membrane cleaning. Results, so far, are very encouraging and may have an important impact on increasing the use of polypropylene MF membranes in oily wastewater treatments.
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Thompson, Phillip L., Chris R. Kemly, Amanda Connell, Kathryn V. Nolan, David Jacobs, Jr., and Gerald Omar A. Ongoco. "Evaluation of Water Treatment Systems for Medical Clinics." International Journal for Service Learning in Engineering, Humanitarian Engineering and Social Entrepreneurship 7, no. 1 (May 30, 2012): 15–27. http://dx.doi.org/10.24908/ijsle.v7i1.4245.
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A Seattle University senior engineering design team evaluated the treatment performance of a point-of-use microfiltration-ultraviolet light (MF-UV) drinking water treatment system and of an ultrafiltration (UF) unit. The MF-UV system reduced turbidity by 70 percent and inactivated 100 percent of E.coli from model water. The UF system removed 100 percent of all turbidity and bacteria. The combined MF-UF-UV treatment system can provide up to 33,120 liters of water per day and meet basic human water needs at an annual cost of approximately US$0.80 per capita. To maintain safe water quality during transport and storage, on-site generated chlorine can be added to the MF-UF-UV treated water. The team evaluated the performance of a chlorine generator and confirmed that chlorine testing strips were excellent surrogates for the N,N-diethyl-p-phenylenediamine (DPD) colorimetric method. Public-private partnerships may be required to ensure long-term sustainability of these drinking water treatment systems in the developing world.
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Sano, D., Y. Ueki, T. Watanabe, and T. Omura. "Membrane separation of indigenous noroviruses from sewage sludge and treated wastewater." Water Science and Technology 54, no. 3 (August 1, 2006): 77–82. http://dx.doi.org/10.2166/wst.2006.451.
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In this study, feasibility of membrane separation for the removal of indigenous noroviruses (NVs) is evaluated. The indigenous NV gene was never detected from ultrafiltration (UF) permeates of sewage sludge and treated wastewater. Indigenous NV gene was also not detected from permeates of sewage sludge and treated wastewater by microfiltration (MF) with a pore size of 0.1 μm (MF0.1). Even though the pore size of MF (0.1 μm) was much larger than the diameter of virus particle (approximately 30–40 nm), more than 4-log10 reduction value (LRV) at maximum was achieved by membrane separation with MF0.1. NV genes were often detected from permeates of sewage sludge and treated wastewater by MF with a pore size of 0.45 μm (MF0.45), although the maximum log10 reduction values were more than 3.59 for sewage sludge and more than 2.90 for treated wastewater. It is important to verify factors determining the removal efficiency of viruses with MF membranes.
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ZHAO, DONGJUN, JESSIE USAGA BARRIENTOS, QING WANG, SARAH M. MARKLAND, JOHN J. CHUREY, OLGA I. PADILLA-ZAKOUR, RANDY W. WOROBO, KALMIA E. KNIEL, and CARMEN I. MORARU. "Efficient Reduction of Pathogenic and Spoilage Microorganisms from Apple Cider by Combining Microfiltration with UV Treatment." Journal of Food Protection 78, no. 4 (April 1, 2015): 716–22. http://dx.doi.org/10.4315/0362-028x.jfp-14-452.
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Thermal pasteurization can achieve the U.S. Food and Drug Administration–required 5-log reduction of pathogenic Escherichia coli O157:H7 and Cryptosporidium parvum in apple juice and cider, but it can also negatively affect the nutritional and organoleptic properties of the treated products. In addition, thermal pasteurization is only marginally effective against the acidophilic, thermophilic, and spore-forming bacteria Alicyclobacillus spp., which is known to cause off-flavors in juice products. In this study, the efficiency of a combined microfiltration (MF) and UV process as a nonthermal treatment for the reduction of pathogenic and nonpathogenic E. coli, C. parvum, and Alicyclobacillus acidoterrestris from apple cider was investigated. MF was used to physically remove suspended solids and microorganisms from apple cider, thus enhancing the effectiveness of UV and allowing a lower UV dose to be used. MF, with ceramic membranes (pore sizes, 0.8 and 1.4 μm), was performed at a temperature of 10°C and a transmembrane pressure of 155 kPa. The subsequent UV treatment was conducted using at a low UV dose of 1.75 mJ/cm2. The combined MF and UV achieved more than a 5-log reduction of E. coli, C. parvum, and A. acidoterrestris. MF with the 0.8-μm pore size performed better than the 1.4-μm pore size on removal of E. coli and A. acidoterrestris. The developed nonthermal hurdle treatment has the potential to significantly reduce pathogens, as well as spores, yeasts, molds, and protozoa in apple cider, and thus help juice processors improve the safety and quality of their products.
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Yun, Taek Gun, Yun Jin Kim, Sang Ho Lee, Jin Sik Sohn, and June Seok Choi. "Development of Dynamically-Formed Membranes Using Colloidal Silica and Kaolin." Materials Science Forum 724 (June 2012): 229–32. http://dx.doi.org/10.4028/www.scientific.net/msf.724.229.
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Low pressure membranes such as microfiltration (MF) and ultrafiltration (UF) have been widely used for water and wastewater treatment. However, most MF and UF membranes are made of polymeric materials, leading to limited resistance to external streeses. Ceramic membranes are also used but they are more expensive than the polymeric membranes. In this study, novel inorganic membranes were developed for water treatment applications. Colloidal silica and kaolin were used to form dynamic membranes. Stainless steel filter was used as supports for the dynamic membranes. Laboratory-scale systems were used to evaluate their potential and performance. Water permeability and turbidity removal were monitored to confirm their initial efficiency and long-term stability.
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Park, Sangwoo, Dongyeop Kim, and Jin Yong Park. "The Function of Adsorption, Photo-Oxidation, and Humic Acid Using Air Backwashing in Integrated Water Treatment of Multichannel Ceramic MF and PP Particles." Membranes 10, no. 2 (February 11, 2020): 28. http://dx.doi.org/10.3390/membranes10020028.
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For advanced water treatment, function of microfiltration (MF), adsorption, photo-oxidation, humic acid (HA), and polypropylene (PP) particles on membrane fouling and decay effectiveness were investigated in an integrated water treatment, of multichannel ceramic MF and PP particles, using UV radiation and air backwashing. The synthetic feed was organized with HA and kaolin. The membrane fouling resistance (Rf) of the (MF + PP) system presented the lowermost, and amplified intensely from the (MF + UV) to MF system. The percentages of MF and adsorption by PP particles for turbidity treatment were 87.6% and 3.8%, individually; however, the percentages of MF and adsorption by PP particles for dissolved organic matters (DOM) treatment were 27.9% and 5.0%, respectively. The decay effectiveness of turbidity presented the greatest 95.4% at HA of 10 mg/L; however, that of DOM increased as HA concentration ascended. The ultimate Rf after 180 min procedure showed the maximum at 30 g/L of PP particles concentration, and improved dramatically, as PP particles decreased. Finally, the maximum VT was acquired at 30 and 50 g/L of PP particles, because flux preserved greater throughout the procedure. The decay effectiveness of turbidity and DOM showed the maximal 95.4% and 56.8% at 40 and 50 g/L of PP particles, respectively.
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Mejia, Jaime A. Arboleda, and Jorge Yáñez-Fernandez. "Clarification Processes of Orange Prickly Pear Juice (Opuntia spp.) by Microfiltration." Membranes 11, no. 5 (May 12, 2021): 354. http://dx.doi.org/10.3390/membranes11050354.
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In this study, fresh orange prickly pear juice (Opuntia spp.) was clarified by a cross-flow microfiltration (MF) process on a laboratory scale. The viability of the process—in terms of productivity (permeate flux of 77.80 L/h) and the rejection of selected membranes towards specific compounds—was analyzed. The quality of the clarified juice was also analyzed for total antioxidants (TEAC), betalains content (mg/100 g wet base), turbidity (NTU) and colorimetry parameters (L, a*, b*, Croma and H). The MF process permitted an excellent level of clarification, reducing the suspended solids and turbidity of the fresh juice. In the clarified juice, a decrease in total antioxidants (2.03 TEAC) and betalains content (4.54 mg/100 g wet basis) was observed as compared to the fresh juice. Furthermore, there were significant changes in color properties due to the effects of the L, a*, b*, C and h° values after removal of turbidity of the juice. The turbidity also decreased (from 164.33 to 0.37 NTU).
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Liu, Qi Feng, Qi Wang, Shao Hui Yan, and Ji Zhao. "The Optimization of Operation Parameters of Microfiltration Membrane System." Advanced Materials Research 726-731 (August 2013): 1770–73. http://dx.doi.org/10.4028/www.scientific.net/amr.726-731.1770.
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The sustainable flux in dead-end mode of MF membrane filtration was confirmed in this study. Analytic results show that when flux above which an irreversible deposit (fouling) appears. The sustainable flux is dependent on the hydrodynamics and system properties (pH, ionic strength, membrane characteristics, particle characteristics, etc) and position along the membrane. Below the sustainable flux, tiny fouling is observed. In addition, the optimal pre-coagulation condition was found based on the maximum turbidity and organic remove rate.
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Hatt, J. W., E. Germain, and S. J. Judd. "Granular activated carbon for removal of organic matter and turbidity from secondary wastewater." Water Science and Technology 67, no. 4 (February 1, 2013): 846–53. http://dx.doi.org/10.2166/wst.2012.644.
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A range of commercial granular activated carbon (GAC) media have been assessed as pretreatment technologies for a downstream microfiltration (MF) process. Media were assessed on the basis of reduction in both organic matter and turbidity, since these are known to cause fouling in MF membranes. Isotherm adsorption analysis through jar testing with supplementary column trials revealed a wide variation between the different adsorbent materials with regard to organics removal and adsorption kinetics. Comparison with previous work using powdered activated carbon (PAC) revealed that for organic removal above 60% the use of GAC media incurs a significantly lower carbon usage rate than PAC. All GACs tested achieved a minimum of 80% turbidity removal. This combination of turbidity and organic removal suggests that GAC would be expected to provide a significant reduction in fouling of a downstream MF process with improved product water quality.
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Kang, Joon-Seok, Ramon Christian Eusebio, and Han-Seung Kim. "Boron removal by activated carbon and microfiltration for pre-treatment of seawater desalination." Water Supply 11, no. 5 (December 1, 2011): 560–67. http://dx.doi.org/10.2166/ws.2011.086.
Full textAbstract:
This study aimed to enhance boron removal through powdered activated carbon adsorption (PAC) and application of a micro-filtration (MF) process as a pretreatment of a seawater reverse osmosis (SWRO) process. Batch and continuous experiments were conducted to investigate the effect of membrane filtration as well as PAC addition on boron removal in reconstituted seawater. In batch test, two kinds of polyvinylidene fluoride (PVDF) hollow fiber membrane, Module A and Module B, were used to assess the influence of pH and PAC on boron removal, whereas in continuous mode, two MF systems with submerged PVDF flat-sheet membrane were run in parallel. Modules A and B obtained the highest percentage boron removal at pH 9 in the batch experiment with an average value of 47.33%, and their concentration of boron was further reduced after addition of PAC increasing the removal to 51.33 and 69.33%, respectively. For the continuous operation, PAC addition decreased the boron concentration by 20–30 and 40% in the reactor and effluent, respectively. On the other hand, only 5% reduction was obtained inside the reactor and 30–40% in the effluent for the system without PAC. Thus, operating the system at high pH with PAC addition could enhance the performance of the adsorption-MF system, which can be used as a pretreatment for the SWRO process.
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Chen, Gui E., Ying Zhou, Zhen Liang Xu, and Qiong Lu. "Cake Fouling Mechanism and Analysis of Synthetic Coke Wastewater Treatment by Membrane Bioreactor." Advanced Materials Research 233-235 (May 2011): 953–58. http://dx.doi.org/10.4028/www.scientific.net/amr.233-235.953.
Full textAbstract:
Cake fouling mechanism was studied for membrane bioreactor (MBR) treatment of synthetic coke wastewater. Cake fouling characteristics of the aerobic activated sludge from MBR was investigated. The experimental results demonstrated that the cake governing equation fit the entire cake microfiltration (MF) process while cake fouling model was applicable to simulate the decrease in permeability and was used to predict the cake fouling development for both PVDF and PP MF membranes. Based on four-step development progresses, cake formation mechanism had been depicted with the increasing of TMP and the reduction of the cake porosity ratio. In addition, the comparison experiments under different operation modes were performed to further analyze the cake governing mechanism for MBR filtration.
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Nguyen, T., L. Fan, F. A. Roddick, and J. L. Harris. "Identification of key water quality characteristics affecting the filterability of biologically treated effluent in low-pressure membrane filtration." Water Science and Technology 62, no. 8 (August 1, 2010): 1914–21. http://dx.doi.org/10.2166/wst.2010.531.
Full textAbstract:
There are many water quality characteristics which could influence the filterability of biologically treated effluent from Melbourne's Western Treatment Plant (WTP). Statistical correlation was used to identify the key water characteristics affecting the microfiltration (MF) and ultrafiltration (UF) filterability in terms of permeate volume of the treated effluent. The models developed showed that turbidity, dissolved organic carbon (DOC) and total suspended solids (TSS) were the key factors which influenced the MF and UF filterability. Turbidity was the dominant factor affecting the accuracy of the model for MF filterability while DOC was the major factor affecting the accuracy of the model for UF filterability. A prediction accuracy of 85% was obtained for MF and 86% for UF filterability of the WTP effluent. The characteristics of the organic components of the wastewater were demonstrated by EEM spectra to have seasonal variation which would have reduced the prediction accuracy. As turbidity, DOC and TSS can be determined on-line, the models would be useful for rapid prediction of the filterability of WTP effluent and this may assist the control of low-pressure membrane filtration processes.