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Jean-claude Brun-cottan - One of the best experts on this subject based on the ideXlab platform.
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Flocculation Potential of Estuarine Particles: The Importance of Environmental Factors and of the Spatial and Seasonal Variability of Suspended Particulate Matter
Estuaries and Coasts, 2009Co-Authors: Romaric Verney, Robert Lafite, Jean-claude Brun-cottanAbstract:Estuarine systems are complex environments where seasonal and spatial variations occur in concentrations of suspended particulate matter, in primary constituents, and in organic matter content. This study investigated in the laboratory the Flocculation potential of estuarine-suspended particulate matter throughout the year in order to better identify the controlling factors and their hierarchy. Kinetic experiments were performed in the lab with a “video in lab” device, based on a jar test technique, using suspended sediments sampled every 2 months over a 14-month period at three stations in the Seine estuary (France). These sampling stations are representative of (1) the upper estuary, dominated by freshwater, and (2) the middle estuary, characterized by a strong salinity gradient and the presence of an estuarine turbidity maximum. Experiments were performed at a constant low turbulent shear stress characteristic of slack water periods (i.e., a Kolmogorov microscale >1,000 µm). Flocculation processes were estimated using three parameters: Flocculation efficiency, Flocculation speed, and Flocculation time. Results showed that the Flocculation that occurred at the three stations was mainly influenced by the concentration of the suspended particulate matter: maximum floc size was observed for concentrations above 0.1 g l^−1 while no Flocculation was observed for concentrations below 0.004 g l^−1. Diatom blooms strongly enhanced Flocculation speed and, to a lesser extent, Flocculation efficiency. During this period, the maximum Flocculation speed of 6 µm min^−1 corresponded to a Flocculation time of less than 20 min. Salinity did not appear to automatically enhance Flocculation, which depended on the constituents of suspended sediments and on the content and concentration of organic matter. Examination of the variability of 2D fractal dimension during Flocculation experiments revealed restructuring of flocs during aggregation. This was observed as a rapid decrease in the floc fractal dimension from 2 to 1.4 during the first minutes of the Flocculation stage, followed by a slight increase up to 1.8. DeFlocculation experiments enabled determination of the influence of turbulent structures on Flocculation processes and confirmed that turbulent intensity is one of the main determining factors of maximum floc size.
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Flocculation Potential of Estuarine Particles: The Importance of Environmental Factors and of the Spatial and Seasonal Variability of Suspended Particulate Matter
Estuaries and Coasts, 2009Co-Authors: Romaric Verney, Robert Lafite, Jean-claude Brun-cottanAbstract:Estuarine systems are complex environments where seasonal and spatial variations occur in concentrations of suspended particulate matter, in primary constituents, and in organic matter content. This study investigated in the laboratory the Flocculation potential of estuarine-suspended particulate matter throughout the year in order to better identify the controlling factors and their hierarchy. Kinetic experiments were performed in the lab with a “video in lab” device, based on a jar test technique, using suspended sediments sampled every 2 months over a 14-month period at three stations in the Seine estuary (France). These sampling stations are representative of (1) the upper estuary, dominated by freshwater, and (2) the middle estuary, characterized by a strong salinity gradient and the presence of an estuarine turbidity maximum. Experiments were performed at a constant low turbulent shear stress characteristic of slack water periods (i.e., a Kolmogorov microscale >1,000 μm). Flocculation processes were estimated using three parameters: Flocculation efficiency, Flocculation speed, and Flocculation time. Results showed that the Flocculation that occurred at the three stations was mainly influenced by the concentration of the suspended particulate matter: maximum floc size was observed for concentrations above 0.1 g l−1 while no Flocculation was observed for concentrations below 0.004 g l−1. Diatom blooms strongly enhanced Flocculation speed and, to a lesser extent, Flocculation efficiency. During this period, the maximum Flocculation speed of 6 μm min−1 corresponded to a Flocculation time of less than 20 min. Salinity did not appear to automatically enhance Flocculation, which depended on the constituents of suspended sediments and on the content and concentration of organic matter. Examination of the variability of 2D fractal dimension during Flocculation experiments revealed restructuring of flocs during aggregation. This was observed as a rapid decrease in the floc fractal dimension from 2 to 1.4 during the first minutes of the Flocculation stage, followed by a slight increase up to 1.8. DeFlocculation experiments enabled determination of the influence of turbulent structures on Flocculation processes and confirmed that turbulent intensity is one of the main determining factors of maximum floc size. Keywords Flocculation
Romaric Verney - One of the best experts on this subject based on the ideXlab platform.
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Flocculation Potential of Estuarine Particles: The Importance of Environmental Factors and of the Spatial and Seasonal Variability of Suspended Particulate Matter
Estuaries and Coasts, 2009Co-Authors: Romaric Verney, Robert Lafite, Jean-claude Brun-cottanAbstract:Estuarine systems are complex environments where seasonal and spatial variations occur in concentrations of suspended particulate matter, in primary constituents, and in organic matter content. This study investigated in the laboratory the Flocculation potential of estuarine-suspended particulate matter throughout the year in order to better identify the controlling factors and their hierarchy. Kinetic experiments were performed in the lab with a “video in lab” device, based on a jar test technique, using suspended sediments sampled every 2 months over a 14-month period at three stations in the Seine estuary (France). These sampling stations are representative of (1) the upper estuary, dominated by freshwater, and (2) the middle estuary, characterized by a strong salinity gradient and the presence of an estuarine turbidity maximum. Experiments were performed at a constant low turbulent shear stress characteristic of slack water periods (i.e., a Kolmogorov microscale >1,000 µm). Flocculation processes were estimated using three parameters: Flocculation efficiency, Flocculation speed, and Flocculation time. Results showed that the Flocculation that occurred at the three stations was mainly influenced by the concentration of the suspended particulate matter: maximum floc size was observed for concentrations above 0.1 g l^−1 while no Flocculation was observed for concentrations below 0.004 g l^−1. Diatom blooms strongly enhanced Flocculation speed and, to a lesser extent, Flocculation efficiency. During this period, the maximum Flocculation speed of 6 µm min^−1 corresponded to a Flocculation time of less than 20 min. Salinity did not appear to automatically enhance Flocculation, which depended on the constituents of suspended sediments and on the content and concentration of organic matter. Examination of the variability of 2D fractal dimension during Flocculation experiments revealed restructuring of flocs during aggregation. This was observed as a rapid decrease in the floc fractal dimension from 2 to 1.4 during the first minutes of the Flocculation stage, followed by a slight increase up to 1.8. DeFlocculation experiments enabled determination of the influence of turbulent structures on Flocculation processes and confirmed that turbulent intensity is one of the main determining factors of maximum floc size.
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Flocculation Potential of Estuarine Particles: The Importance of Environmental Factors and of the Spatial and Seasonal Variability of Suspended Particulate Matter
Estuaries and Coasts, 2009Co-Authors: Romaric Verney, Robert Lafite, Jean-claude Brun-cottanAbstract:Estuarine systems are complex environments where seasonal and spatial variations occur in concentrations of suspended particulate matter, in primary constituents, and in organic matter content. This study investigated in the laboratory the Flocculation potential of estuarine-suspended particulate matter throughout the year in order to better identify the controlling factors and their hierarchy. Kinetic experiments were performed in the lab with a “video in lab” device, based on a jar test technique, using suspended sediments sampled every 2 months over a 14-month period at three stations in the Seine estuary (France). These sampling stations are representative of (1) the upper estuary, dominated by freshwater, and (2) the middle estuary, characterized by a strong salinity gradient and the presence of an estuarine turbidity maximum. Experiments were performed at a constant low turbulent shear stress characteristic of slack water periods (i.e., a Kolmogorov microscale >1,000 μm). Flocculation processes were estimated using three parameters: Flocculation efficiency, Flocculation speed, and Flocculation time. Results showed that the Flocculation that occurred at the three stations was mainly influenced by the concentration of the suspended particulate matter: maximum floc size was observed for concentrations above 0.1 g l−1 while no Flocculation was observed for concentrations below 0.004 g l−1. Diatom blooms strongly enhanced Flocculation speed and, to a lesser extent, Flocculation efficiency. During this period, the maximum Flocculation speed of 6 μm min−1 corresponded to a Flocculation time of less than 20 min. Salinity did not appear to automatically enhance Flocculation, which depended on the constituents of suspended sediments and on the content and concentration of organic matter. Examination of the variability of 2D fractal dimension during Flocculation experiments revealed restructuring of flocs during aggregation. This was observed as a rapid decrease in the floc fractal dimension from 2 to 1.4 during the first minutes of the Flocculation stage, followed by a slight increase up to 1.8. DeFlocculation experiments enabled determination of the influence of turbulent structures on Flocculation processes and confirmed that turbulent intensity is one of the main determining factors of maximum floc size. Keywords Flocculation
Rafael A Garcia - One of the best experts on this subject based on the ideXlab platform.
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proteins and peptides as renewable flocculants
Bioresource Technology, 2010Co-Authors: George J Piazza, Rafael A GarciaAbstract:Abstract Partially hydrolyzed extracts from blood meal, feather meal, and meat and bone meal, as well as a variety of common surplus agricultural proteins were tested for their ability to promote the Flocculation of clay. Partial alkaline or enzymatic hydrolyses of blood meal, feather meal, and meat and bone meal were performed to liberate proteins and peptides from their water-insoluble forms. Some of these extracts promoted Flocculation. However, if hydrolysis was extensive, low molecular weight peptides were mainly produced, and these extracts did not promote Flocculation. Beef skin gelatins and hydrolyzed fish collagen were found to promote Flocculation when pH 5.5 buffer was added. Commercial preparations of peptone enzymatic digest and a mixture of keratin and hydrolyzed keratin did not promote Flocculation.
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meat bone meal extract and gelatin as renewable flocculants
Bioresource Technology, 2010Co-Authors: George J Piazza, Rafael A GarciaAbstract:Readily available proteins were tested as renewable flocculants, and their actions were compared to that of anionic PAM, a common, commercial flocculant that requires the coaddition of a calcium ion source. Two soy proteins, a whey fraction, a porcine gelatin, and a meat & bone meal (MBM) extract were used in the Flocculation test. It was found that MBM extract and porcine gelatin promoted clay Flocculation, and Flocculation was complete by 24 h with or without the addition of calcium chloride. The other tested proteins did not promote clay Flocculation, but all of the proteins were found to be adsorbed to clay. The protein adsorptions were well described by the Langmuir model, and gelatin and MBM extract had higher maximum adsorption capacities than the other proteins. Zwitterionic buffer solutions at pH 5.5, 7.0, and 10.0 were tested in the Flocculation experiments. Addition of the pH 5.5 buffer caused the two soy proteins to become clay flocculants and lowered the concentration of gelatin and MBM extract necessary to promote complete Flocculation by 24 h. Calcium chloride was not required for Flocculation. Under optimal testing conditions, the dried weight of gelatin or MBM extract was 2.6 and 17 times higher, respectively, than the weight of anionic PAM required for complete Flocculation at 24 h.
Robert Lafite - One of the best experts on this subject based on the ideXlab platform.
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Flocculation Potential of Estuarine Particles: The Importance of Environmental Factors and of the Spatial and Seasonal Variability of Suspended Particulate Matter
Estuaries and Coasts, 2009Co-Authors: Romaric Verney, Robert Lafite, Jean-claude Brun-cottanAbstract:Estuarine systems are complex environments where seasonal and spatial variations occur in concentrations of suspended particulate matter, in primary constituents, and in organic matter content. This study investigated in the laboratory the Flocculation potential of estuarine-suspended particulate matter throughout the year in order to better identify the controlling factors and their hierarchy. Kinetic experiments were performed in the lab with a “video in lab” device, based on a jar test technique, using suspended sediments sampled every 2 months over a 14-month period at three stations in the Seine estuary (France). These sampling stations are representative of (1) the upper estuary, dominated by freshwater, and (2) the middle estuary, characterized by a strong salinity gradient and the presence of an estuarine turbidity maximum. Experiments were performed at a constant low turbulent shear stress characteristic of slack water periods (i.e., a Kolmogorov microscale >1,000 µm). Flocculation processes were estimated using three parameters: Flocculation efficiency, Flocculation speed, and Flocculation time. Results showed that the Flocculation that occurred at the three stations was mainly influenced by the concentration of the suspended particulate matter: maximum floc size was observed for concentrations above 0.1 g l^−1 while no Flocculation was observed for concentrations below 0.004 g l^−1. Diatom blooms strongly enhanced Flocculation speed and, to a lesser extent, Flocculation efficiency. During this period, the maximum Flocculation speed of 6 µm min^−1 corresponded to a Flocculation time of less than 20 min. Salinity did not appear to automatically enhance Flocculation, which depended on the constituents of suspended sediments and on the content and concentration of organic matter. Examination of the variability of 2D fractal dimension during Flocculation experiments revealed restructuring of flocs during aggregation. This was observed as a rapid decrease in the floc fractal dimension from 2 to 1.4 during the first minutes of the Flocculation stage, followed by a slight increase up to 1.8. DeFlocculation experiments enabled determination of the influence of turbulent structures on Flocculation processes and confirmed that turbulent intensity is one of the main determining factors of maximum floc size.
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Flocculation Potential of Estuarine Particles: The Importance of Environmental Factors and of the Spatial and Seasonal Variability of Suspended Particulate Matter
Estuaries and Coasts, 2009Co-Authors: Romaric Verney, Robert Lafite, Jean-claude Brun-cottanAbstract:Estuarine systems are complex environments where seasonal and spatial variations occur in concentrations of suspended particulate matter, in primary constituents, and in organic matter content. This study investigated in the laboratory the Flocculation potential of estuarine-suspended particulate matter throughout the year in order to better identify the controlling factors and their hierarchy. Kinetic experiments were performed in the lab with a “video in lab” device, based on a jar test technique, using suspended sediments sampled every 2 months over a 14-month period at three stations in the Seine estuary (France). These sampling stations are representative of (1) the upper estuary, dominated by freshwater, and (2) the middle estuary, characterized by a strong salinity gradient and the presence of an estuarine turbidity maximum. Experiments were performed at a constant low turbulent shear stress characteristic of slack water periods (i.e., a Kolmogorov microscale >1,000 μm). Flocculation processes were estimated using three parameters: Flocculation efficiency, Flocculation speed, and Flocculation time. Results showed that the Flocculation that occurred at the three stations was mainly influenced by the concentration of the suspended particulate matter: maximum floc size was observed for concentrations above 0.1 g l−1 while no Flocculation was observed for concentrations below 0.004 g l−1. Diatom blooms strongly enhanced Flocculation speed and, to a lesser extent, Flocculation efficiency. During this period, the maximum Flocculation speed of 6 μm min−1 corresponded to a Flocculation time of less than 20 min. Salinity did not appear to automatically enhance Flocculation, which depended on the constituents of suspended sediments and on the content and concentration of organic matter. Examination of the variability of 2D fractal dimension during Flocculation experiments revealed restructuring of flocs during aggregation. This was observed as a rapid decrease in the floc fractal dimension from 2 to 1.4 during the first minutes of the Flocculation stage, followed by a slight increase up to 1.8. DeFlocculation experiments enabled determination of the influence of turbulent structures on Flocculation processes and confirmed that turbulent intensity is one of the main determining factors of maximum floc size. Keywords Flocculation
Meftuni Yekeler - One of the best experts on this subject based on the ideXlab platform.
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shear Flocculation of celestite with sodium oleate and tallow amine acetate effects of cations
Journal of Colloid and Interface Science, 2004Co-Authors: A. Ozkan, Meftuni YekelerAbstract:Abstract Sodium oleate and tallow amine acetate (TAA) were used as surfactants for the shear Flocculation of celestite. The shear-Flocculation power values obtained with sodium oleate were higher than those obtained with TAA in terms of the concentrations used in the shear-Flocculation experiments. In addition, sodium oleate and TAA were more effective on the celestite suspension in the pH ranges of 7–11 and 6–10, respectively. For the shear-Flocculation experiments with sodium oleate at pH 11, with preaddition of calcium or magnesium ions at 5×10−5 M and lower concentrations into the suspension, the shear Flocculation of the celestite suspension was promoted by the coagulation process due to the calcium and magnesium cations added. However, the shear-Flocculation power values decreased due to the interaction between surfactant and cations at concentration values higher than 5×10−5 M for magnesium ions and 10−3 M for calcium ion. Particularly, magnesium ions significantly reduced the shear-Flocculation power values by slime coating of Mg(OH)2 precipitates.