The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
P Moulin - One of the best experts on this subject based on the ideXlab platform.
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treatment process adapted to stabilized leachates lime precipitation Prefiltration reverse osmosis
Journal of Membrane Science, 2008Co-Authors: S Renou, S Poulain, J G Givaudan, P MoulinAbstract:Abstract Leachates are generated from municipal waste landfills under the action of water percolating through the landfilled waste. These leachates contain high amounts of inorganic and organic matter and must imperatively be treated before being discharged into the environment. Reverse osmosis is the most widely used method for treating these leachates, since it produces a permeate in compliance with the increasingly strict reject requirements and a retentate containing high concentrations of organic material and inorganic salts. However, the efficiency of this process at the industrial scale is limited mainly because of membrane fouling and the high osmotic pressures involved. A suitable pretreatment is required to overcome these limitations. This paper presents the development and optimization of an innovative combination of processes for the treatment of landfill leachates. This process combination consists in a chemical precipitation of the leachate using lime, followed by a standard filtration on a rotary drum vacuum precoat filter which separates the precipitated phase from the liquid phase before the final step of reverse osmosis. Coupling these processes makes it possible (i) to decrease the salinity of the effluent by 15–30% through precipitation of the metals and carbonates, thereby facilitating RO operation by decreasing the osmotic pressure, (ii) to eliminate by co-precipitation the humic acids responsible for irreversible membrane fouling, (iii) to generate a sludge that is stable, chemically inert, relatively dry (50% siccity) and that can be easily stored on an adequate site. At the industrial scale, it makes it possible to decrease the working pressures as well as the concentrate volumes (or residues) generated and at the same time increase the conversion rate of RO process. It can also make it possible to reduce the frequency of membrane cleaning and the consumption of cleaning chemicals.
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Treatment process adapted to stabilized leachates: Lime precipitation–Prefiltration–reverse osmosis
Journal of Membrane Science, 2008Co-Authors: S Renou, S Poulain, J G Givaudan, P MoulinAbstract:Abstract Leachates are generated from municipal waste landfills under the action of water percolating through the landfilled waste. These leachates contain high amounts of inorganic and organic matter and must imperatively be treated before being discharged into the environment. Reverse osmosis is the most widely used method for treating these leachates, since it produces a permeate in compliance with the increasingly strict reject requirements and a retentate containing high concentrations of organic material and inorganic salts. However, the efficiency of this process at the industrial scale is limited mainly because of membrane fouling and the high osmotic pressures involved. A suitable pretreatment is required to overcome these limitations. This paper presents the development and optimization of an innovative combination of processes for the treatment of landfill leachates. This process combination consists in a chemical precipitation of the leachate using lime, followed by a standard filtration on a rotary drum vacuum precoat filter which separates the precipitated phase from the liquid phase before the final step of reverse osmosis. Coupling these processes makes it possible (i) to decrease the salinity of the effluent by 15–30% through precipitation of the metals and carbonates, thereby facilitating RO operation by decreasing the osmotic pressure, (ii) to eliminate by co-precipitation the humic acids responsible for irreversible membrane fouling, (iii) to generate a sludge that is stable, chemically inert, relatively dry (50% siccity) and that can be easily stored on an adequate site. At the industrial scale, it makes it possible to decrease the working pressures as well as the concentrate volumes (or residues) generated and at the same time increase the conversion rate of RO process. It can also make it possible to reduce the frequency of membrane cleaning and the consumption of cleaning chemicals.
Annsofi Jonsson - One of the best experts on this subject based on the ideXlab platform.
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influence of air and nitrogen sparging on flux during ultrafiltration of hemicelluloses extracted from wheat bran
Separation and Purification Technology, 2019Co-Authors: Johan Thuvander, Annsofi JonssonAbstract:Abstract Ultrafiltration can be used to concentrate arabinoxylan isolated from wheat bran. Prefiltration with diatomaceous earth and air sparging during ultrafiltration of the alkaline hemicellulose solution were both found to increase the flux, while nitrogen sparging had no effect. The flux of the untreated solution was 51 L/m2 h, while the flux after Prefiltration of the solution with diatomaceous earth was 62 L/m2 h. After 5 h of air sparging during ultrafiltration of the prefiltered solution the flux was 230 L/m2 h. However, sparging the prefiltered solution with nitrogen gas had no effect on the flux. This shows that the increase in flux was not due to the reduction of concentration polarization by sparging per se. Size-exclusion chromatography showed that sparging with air caused a reduction in the size of hemicelluloses >100 kDa to 10–100 kDa, which is believed to be due to oxidative degradation of hemicelluloses. This size reduction of the hemicelluloses is likely the main cause of the increased flux. The retention of hemicelluloses during ultrafiltration with a ceramic membrane with a nominal cut-off of 10 kDa was 96% in all experiments, except at the end of the experiment with the prefiltered, air-sparged solution, when the retention decreased to 93% due to the size reduction of the hemicelluloses. Air sparging seems to be an efficient flux enhancing method with limited negative influence on the molecular size of hemicelluloses.
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impact of Prefiltration on membrane performance during isolation of hemicelluloses extracted from wheat bran
Separation and Purification Technology, 2013Co-Authors: Holger Krawczyk, Anders Arkell, Annsofi JonssonAbstract:Hemicelluloses extracted from wheat bran have to be separated from impurities in order to obtain a valuable product at high concentration and purity. A previous investigation showed that separation by ultrafiltration is possible, but the flux was low due to the high viscosity of the solution and the presence of gel-forming substances in the solution. In this investigation the influence of Prefiltration on solution viscosity and ultrafiltration performance was investigated. The viscosity of the hemicellulose solution after extraction was considerably reduced with both Prefiltration methods tested, leading to a substantial increase in flux during ultrafiltration. The highest flux achieved without pretreatment was about 75 l/m2 h, and was increased to 225 and 440 l/m2 h after dead-end filtration and microfiltration, respectively. However, the loss of hemicelluloses was considerable during microfiltration, but <5% during dead-end filtration. After Prefiltration by dead-end filtration, hemicelluloses could be successfully concentrated and purified by ultrafiltration. Eighty percent of the initial volume was removed during concentration at an average flux of 155 l/m2 h. At the same time, the concentration and purity of the hemicelluloses increased from 7.6 g/l and 15% to 31.6 g/l and 31%, respectively. The results obtained in this investigation indicate that dead-end filtration could be a useful form of pretreatment before ultrafiltration when recovering hemicelluloses extracted from wheat bran.
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Impact of Prefiltration on membrane performance during isolation of hemicelluloses extracted from wheat bran
Separation and Purification Technology, 2013Co-Authors: Holger Krawczyk, Anders Arkell, Annsofi JonssonAbstract:Hemicelluloses extracted from wheat bran have to be separated from impurities in order to obtain a valuable product at high concentration and purity. A previous investigation showed that separation by ultrafiltration is possible, but the flux was low due to the high viscosity of the solution and the presence of gel-forming substances in the solution. In this investigation the influence of Prefiltration on solution viscosity and ultrafiltration performance was investigated. The viscosity of the hemicellulose solution after extraction was considerably reduced with both Prefiltration methods tested, leading to a substantial increase in flux during ultrafiltration. The highest flux achieved without pretreatment was about 75 l/m2 h, and was increased to 225 and 440 l/m2 h after dead-end filtration and microfiltration, respectively. However, the loss of hemicelluloses was considerable during microfiltration, but
S Renou - One of the best experts on this subject based on the ideXlab platform.
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treatment process adapted to stabilized leachates lime precipitation Prefiltration reverse osmosis
Journal of Membrane Science, 2008Co-Authors: S Renou, S Poulain, J G Givaudan, P MoulinAbstract:Abstract Leachates are generated from municipal waste landfills under the action of water percolating through the landfilled waste. These leachates contain high amounts of inorganic and organic matter and must imperatively be treated before being discharged into the environment. Reverse osmosis is the most widely used method for treating these leachates, since it produces a permeate in compliance with the increasingly strict reject requirements and a retentate containing high concentrations of organic material and inorganic salts. However, the efficiency of this process at the industrial scale is limited mainly because of membrane fouling and the high osmotic pressures involved. A suitable pretreatment is required to overcome these limitations. This paper presents the development and optimization of an innovative combination of processes for the treatment of landfill leachates. This process combination consists in a chemical precipitation of the leachate using lime, followed by a standard filtration on a rotary drum vacuum precoat filter which separates the precipitated phase from the liquid phase before the final step of reverse osmosis. Coupling these processes makes it possible (i) to decrease the salinity of the effluent by 15–30% through precipitation of the metals and carbonates, thereby facilitating RO operation by decreasing the osmotic pressure, (ii) to eliminate by co-precipitation the humic acids responsible for irreversible membrane fouling, (iii) to generate a sludge that is stable, chemically inert, relatively dry (50% siccity) and that can be easily stored on an adequate site. At the industrial scale, it makes it possible to decrease the working pressures as well as the concentrate volumes (or residues) generated and at the same time increase the conversion rate of RO process. It can also make it possible to reduce the frequency of membrane cleaning and the consumption of cleaning chemicals.
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Treatment process adapted to stabilized leachates: Lime precipitation–Prefiltration–reverse osmosis
Journal of Membrane Science, 2008Co-Authors: S Renou, S Poulain, J G Givaudan, P MoulinAbstract:Abstract Leachates are generated from municipal waste landfills under the action of water percolating through the landfilled waste. These leachates contain high amounts of inorganic and organic matter and must imperatively be treated before being discharged into the environment. Reverse osmosis is the most widely used method for treating these leachates, since it produces a permeate in compliance with the increasingly strict reject requirements and a retentate containing high concentrations of organic material and inorganic salts. However, the efficiency of this process at the industrial scale is limited mainly because of membrane fouling and the high osmotic pressures involved. A suitable pretreatment is required to overcome these limitations. This paper presents the development and optimization of an innovative combination of processes for the treatment of landfill leachates. This process combination consists in a chemical precipitation of the leachate using lime, followed by a standard filtration on a rotary drum vacuum precoat filter which separates the precipitated phase from the liquid phase before the final step of reverse osmosis. Coupling these processes makes it possible (i) to decrease the salinity of the effluent by 15–30% through precipitation of the metals and carbonates, thereby facilitating RO operation by decreasing the osmotic pressure, (ii) to eliminate by co-precipitation the humic acids responsible for irreversible membrane fouling, (iii) to generate a sludge that is stable, chemically inert, relatively dry (50% siccity) and that can be easily stored on an adequate site. At the industrial scale, it makes it possible to decrease the working pressures as well as the concentrate volumes (or residues) generated and at the same time increase the conversion rate of RO process. It can also make it possible to reduce the frequency of membrane cleaning and the consumption of cleaning chemicals.
Mathias Ulbricht - One of the best experts on this subject based on the ideXlab platform.
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ultrafiltration of humic acid solutions through unmodified and surface functionalized low fouling polyethersulfone membranes effects of feed properties molecular weight cut off and membrane chemistry on fouling behavior and cleanability
Separation and Purification Technology, 2011Co-Authors: Polina Dobromirova Peeva, Aisyah Endah Palupi, Mathias UlbrichtAbstract:Abstract In the present work, polyethersulfone (PES) ultrafiltration (UF) membranes with molecular weight cut-off (MWCO) from 5 to 300 kDa were analyzed with respect to fouling during filtration of humic acid (HA) model solution. The impact of MWCO and Prefiltration of the feed solution on the fouling behavior of these membranes is presented. Moreover, an UV-initiated graft copolymerization of poly(ethylene glycol) methacrylate (PEGMA) onto PES membranes was performed and the effect of the applied modification was examined in terms of MWCO and water permeability changes as well as performance during filtration of HA. Moreover, the fouling behavior and principles during the filtration were compared. Membranes with higher MWCO exhibited stronger flux decline during UF but better cleanability. Prefiltration through 0.45 μm filter improved the membrane performance during filtration of HA but the efficiency of physical cleaning was deteriorated. The applied modification improved the membrane performance during ultrafiltration and facilitated the physical cleaning. This work contributes to a better understanding of the relationships between membrane MWCO, solute size and size distribution, membrane surface chemistry and membrane fouling.
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Ultrafiltration of humic acid solutions through unmodified and surface functionalized low-fouling polyethersulfone membranes – Effects of feed properties, molecular weight cut-off and membrane chemistry on fouling behavior and cleanability
Separation and Purification Technology, 2011Co-Authors: Polina Dobromirova Peeva, Aisyah Endah Palupi, Mathias UlbrichtAbstract:Abstract In the present work, polyethersulfone (PES) ultrafiltration (UF) membranes with molecular weight cut-off (MWCO) from 5 to 300 kDa were analyzed with respect to fouling during filtration of humic acid (HA) model solution. The impact of MWCO and Prefiltration of the feed solution on the fouling behavior of these membranes is presented. Moreover, an UV-initiated graft copolymerization of poly(ethylene glycol) methacrylate (PEGMA) onto PES membranes was performed and the effect of the applied modification was examined in terms of MWCO and water permeability changes as well as performance during filtration of HA. Moreover, the fouling behavior and principles during the filtration were compared. Membranes with higher MWCO exhibited stronger flux decline during UF but better cleanability. Prefiltration through 0.45 μm filter improved the membrane performance during filtration of HA but the efficiency of physical cleaning was deteriorated. The applied modification improved the membrane performance during ultrafiltration and facilitated the physical cleaning. This work contributes to a better understanding of the relationships between membrane MWCO, solute size and size distribution, membrane surface chemistry and membrane fouling.
J.h.j.m. Van Der Graaf - One of the best experts on this subject based on the ideXlab platform.
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Prefiltration of wastewater effluent: Effects on foulants and performance during dead end ultrafiltration ☆
Desalination, 2010Co-Authors: A.n. Janssen, J. Van Agtmaal, W.b.p. Van Den Broek, A.j. Geilvoet, H.w.h. Menkveld, Jean-christophe Schrotter, J.h.j.m. Van Der GraafAbstract:Abstract An important trend in the development of ultrafiltration (UF) of wastewater effluent is the integration of pretreatment to improve the performance of membranes. In this paper the results of a study on the effect of three Prefiltration techniques (multimedia filtration, granulated activated carbon filtration and biological activated carbon filtration) on foulants and performance of UF are presented. The objectives of the study are: (1) to establish the different effect of three Prefiltration configurations on performance of UF and foulants of wastewater effluent and (2), to determine in which particle size range the most particles or colloidals are removed after the three Prefiltration configurations. From all of the filters, the biological granulated activated carbon filter (BGAC) presented the highest increase of filterability. During this study, the specific ultrafiltration resistance (SUR) value of the filtrate is always below 5 · 10 12 m − 2 independent on the incoming SUR value. From all the foulants especially the proteins and humic substances are removed by granulated activated carbon filter (GAC) and BGAC. BGAC is the only Prefiltration technique that shows significant removal of the fraction between 0.1 µm and 0.2 µm.
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Prefiltration of wastewater effluent effects on foulants and performance during dead end ultrafiltration
Desalination, 2010Co-Authors: A.n. Janssen, J. Van Agtmaal, W.b.p. Van Den Broek, A.j. Geilvoet, H.w.h. Menkveld, Jean-christophe Schrotter, J.h.j.m. Van Der GraafAbstract:Abstract An important trend in the development of ultrafiltration (UF) of wastewater effluent is the integration of pretreatment to improve the performance of membranes. In this paper the results of a study on the effect of three Prefiltration techniques (multimedia filtration, granulated activated carbon filtration and biological activated carbon filtration) on foulants and performance of UF are presented. The objectives of the study are: (1) to establish the different effect of three Prefiltration configurations on performance of UF and foulants of wastewater effluent and (2), to determine in which particle size range the most particles or colloidals are removed after the three Prefiltration configurations. From all of the filters, the biological granulated activated carbon filter (BGAC) presented the highest increase of filterability. During this study, the specific ultrafiltration resistance (SUR) value of the filtrate is always below 5 · 10 12 m − 2 independent on the incoming SUR value. From all the foulants especially the proteins and humic substances are removed by granulated activated carbon filter (GAC) and BGAC. BGAC is the only Prefiltration technique that shows significant removal of the fraction between 0.1 µm and 0.2 µm.