The Experts below are selected from a list of 3921 Experts worldwide ranked by ideXlab platform
Miklas Scholz - One of the best experts on this subject based on the ideXlab platform.
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Impact of Temperature on Sludge Dewatering Properties Assessed by the Capillary Suction Time
Industrial & Engineering Chemistry Research, 2012Co-Authors: Ola Sawalha, Miklas ScholzAbstract:The impact of temperature on the filterability of synthetic sludge, using the Capillary Suction time (CST) test, was investigated. The CST was measured at five temperatures, six total suspended solid (TSS) concentrations, and two funnel geometries. The results were not consistent with the hypothesis that the CST declines at higher temperatures through the lowering of the sludge viscosity. The impact of temperature on the results of CST tests was moderated by other physicochemical properties of the sludge (desorptivity, particle size composition, and chemical constituents) associated with the efficiency of flocculation.
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modeling the relationship between Capillary Suction time and specific resistance to filtration
Journal of Environmental Engineering, 2010Co-Authors: Ola Sawalha, Miklas ScholzAbstract:The Capillary Suction time (CST) and the specific resistance to filtration (SRF) tests are both commonly used to estimate sludge dewaterability. Both tests are known to be empirically related but the SRF is much more expensive and time consuming compared with the CST test. The aim of this study was therefore to develop a prediction methodology to obtain SRF test results from the data generated by CST tests under different experimental conditions. This study is based on empirical data sets linking CST with SRF. The prediction equations were developed by first estimating filterability from CST values and then relating it with SRF values using regression analyses. The relationships between the results of the CST and SRF tests were best described using an empirical model, which incorporated logarithmic and squared terms to account for the nonlinear relationship between filterability, total suspended solids, and temperature. The findings were statistically significant ( p<0.05 ) and the model satisfied all the...
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Modeling the relationship between Capillary Suction time and specific resistance to filtration
Journal of Environmental Engineering, 2010Co-Authors: Ola Sawalha, Miklas ScholzAbstract:The Capillary Suction time (CST) and the specific resistance to filtration (SRF) tests are both commonly used to estimate sludge dewaterability. Both tests are known to be empirically related but the SRF is much more expensive and time consuming compared with the CST test. The aim of this study was therefore to develop a prediction methodology to obtain SRF test results from the data generated by CST tests under different experimental conditions. This study is based on empirical data sets linking CST with SRF. The prediction equations were developed by first estimating filterability from CST values and then relating it with SRF values using regression analyses. The relationships between the results of the CST and SRF tests were best described using an empirical model, which incorporated logarithmic and squared terms to account for the nonlinear relationship between filterability, total suspended solids, and temperature. The findings were statistically significant ( p
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Innovative enhancement of the design and precision of the Capillary Suction time testing device.
Water environment research : a research publication of the Water Environment Federation, 2009Co-Authors: Ola Sawalha, Miklas ScholzAbstract:The Capillary Suction time (CST) test can be used as an alternative to predict the otherwise expensive, hard-to-run specific resistance to filtration test. One of the major drawbacks of the CST test, however, is relatively high variability of test results. The aim of this study was, therefore, to improve the product design by testing the effectiveness of using a funnel sealant to reduce variability. Use of a funnel sealant resulted in increased test precision. There was a reduction of up to 63% in the coefficient of variation and a substantial improvement in the predictability of the specific resistance to filtration test.
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Assessment of Capillary Suction time (CST) test methodologies.
Environmental technology, 2007Co-Authors: O Sawalha, Miklas ScholzAbstract:The Capillary Suction time (CST) test is a commonly used method to measure the filterability and the easiness of removing moisture from slurry and sludge in numerous environmental and industrial applications. This study assessed several novel alterations of both the test methodology and the current standard Capillary Suction time (CST) apparatus. Twelve different papers including the standard Whatman No. 17 chromatographic paper were tested. The tests were run using four different types of sludge including a synthetic sludge, which was specifically developed for benchmarking purposes. The standard apparatus was altered by the introduction of a novel rectangular funnel instead of a standard circular one. A stirrer was also introduced to solve the problem of test inconsistency (e.g. high CST variability) particularly for heavy types of sludge. Results showed that several alternative papers, which are cheaper than the standard paper, can be used to estimate CST values accurately, and that the test repeatability can be improved in many cases and for different types of sludge. The introduction of the rectangular funnel demonstrated an obvious enhancement of test repeatability. The use of a stirrer to avoid sedimentation of heavy sludge did not have statistically significant impact on the CST values or the corresponding data variability. The application of synthetic sludge can support the testing of experimental methodologies and should be used for subsequent benchmarking purposes.
Y. H. Hsu - One of the best experts on this subject based on the ideXlab platform.
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A Rectangular Capillary Suction Apparatus
Industrial & Engineering Chemistry Research, 1994Co-Authors: Duu-jong Lee, Y. H. HsuAbstract:Fluid flow and cake formation in a rectangular Capillary Suction apparatus (RCSA) are investigated experimentally and theoretically. Water, methanol, ethanol, and ethylene glycol are used to study the effects of liquid properties, and CaCO[sub 3], kaolin, and bentonite slurries are employed for studying the effects of cake formation on Capillary Suction-time (CST). A theory based on a diffusion-like approach is developed. The liquid saturation under the inner cell will approach a constant value when the wet front distance is large. A method based on this experimental finding for estimating the cake specific resistance is proposed. The agreement between experiments and calculations is close. The RCSA is superior to the cylindrical CSA when treating liquids with small diffusivities or slurries with high solid concentration and/or with high averaged specific resistance.
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Use of Capillary Suction apparatus for estimating the averaged specific resistance of filtration cake
Journal of Chemical Technology AND Biotechnology, 1994Co-Authors: Duu-jong Lee, Y. H. HsuAbstract:A method for estimating the averaged specific resistance of filtration cake, which avoids the necessity of measuring the liquid invasion volume in Capillary Suction apparatus (CSA) experiments, is proposed. When insufficient slurry is used, the slurry will exhaust during an experiment and the curve of wet front radius versus time shows transition. The transition point shifts according to the slurry concentration, cake specific resistance and the CSA parameters. Based on the wet front radius and the Capillary Suction time (CST) of the transition point, the liquid saturation under the inner cylinder can be estimated and the averaged specific resistance of cake calculated without the liquid invasion volume data. The proposed method agrees well with vacuum filtration data.
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Cake formation in Capillary Suction apparatus
Industrial & Engineering Chemistry Research, 1993Co-Authors: Duu-jong Lee, Y. H. HsuAbstract:The fluid flow through porous media in Capillary Suction apparatus with cake formation was investigated experimentally and theoretically. Celite, CaCO 3 , kaolin, and bentonite slurries were used to study the effects of cake formation on the filter paper on Capillary Suction time (CST). It was found that the liquid saturation under the inner cylinder during experiments would approach a constant value when the wet front radius was large, under which the condition could be taken as a constant-pressure filtration process. The Capillary Suction pressure versus saturation relation was constructed. A method to estimate the averaged specific resistance from the wet front dynamic data and the liquid invasion volume was proposed. The calculation results showed satisfactory agreement with experiments
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Fluid flow in Capillary Suction apparatus
Industrial & Engineering Chemistry Research, 1992Co-Authors: Duu-jong Lee, Y. H. HsuAbstract:The fluid flow through porous media in Capillary Suction apparatus (CSA) was investigated experimentally and theorically. Water, with and without surfactant additives, methanol, and ethylene glycol were used to study the effects of liquid on Capillary Suction time of apparatus with various column radii and sampling locations. A model based on the saturation-diffusion mechanism was developed. The results showed satisfactory agreement with the experimetal data. A modified Capillary Suction time was proposed based on the model which incorporated only the liquid effect and was independent of the apparatus used. Experiments with kaolin slurry showed that the model could be used to describe the fluid flow behavior in CSA with cake formation, if the liquid saturation under the inner cylinder was taken as less than unity
Duu-jong Lee - One of the best experts on this subject based on the ideXlab platform.
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Liquid Saturation Profile in Capillary Suction Time Filter Paper
Industrial & Engineering Chemistry Research, 2001Co-Authors: W. W. Lin, Duu-jong LeeAbstract:This work reviews pertinent literature in modeling by considering the water movement in filter paper to measure Capillary Suction time (CST). Both the diffusion-like and piston-like approaches are described. In addition, liquid saturation profiles in the filter paper for pure water and some slurries are experimentally constructed. Experimental results indicate that the unsaturated flow in filter paper is unexceptionable in all tests. However, the CST correlations derived from either piston-like or diffusion-like approaches resemble each other in form, which is attributed to the s profile near the wet front resembling a power-law-type behavior.
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ON THE SLOW MANIFOLD CHARACTERISTICS OF Capillary Suction APPARATUS DYNAMICS
Chemical Engineering Communications, 1995Co-Authors: Duu-jong LeeAbstract:The nonlinear dynamic behaviour relating the wet front size and liquid saturation under inner cylinder (or rectangular cell) in cylindrical (or rectangular) Capillary Suction apparatus was investigated. The slow manifold explanation was proposed and the fast- and slow-varying variables were identified. Experiments were conducted to verify theoretical findings.
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A Rectangular Capillary Suction Apparatus
Industrial & Engineering Chemistry Research, 1994Co-Authors: Duu-jong Lee, Y. H. HsuAbstract:Fluid flow and cake formation in a rectangular Capillary Suction apparatus (RCSA) are investigated experimentally and theoretically. Water, methanol, ethanol, and ethylene glycol are used to study the effects of liquid properties, and CaCO[sub 3], kaolin, and bentonite slurries are employed for studying the effects of cake formation on Capillary Suction-time (CST). A theory based on a diffusion-like approach is developed. The liquid saturation under the inner cell will approach a constant value when the wet front distance is large. A method based on this experimental finding for estimating the cake specific resistance is proposed. The agreement between experiments and calculations is close. The RCSA is superior to the cylindrical CSA when treating liquids with small diffusivities or slurries with high solid concentration and/or with high averaged specific resistance.
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A Dynamic Model of Capillary Suction Apparatus
JOURNAL OF CHEMICAL ENGINEERING OF JAPAN, 1994Co-Authors: Duu-jong LeeAbstract:A model for the dynamic behaviour of the wet front radius and the liquid saturation in a Capillary Suction apparatus (CSA) is developed. Governing equations based on mass/momentum balance are derived and solved numerically. The calculation shows that the effects of the initial conditions on system dynamics vanish rapidly, and that the system then evolves along a slow manifold which is independent of the initial conditions chosen. It is also noted that, after sufficient time, the log–log plot of the dimensionless wet front radius versus dimensionless time can be approximated by straight lines and the liquid saturation under the inner cylinder can be taken as constant with error less than 5%. The increase in solids concentration and/or the averaged specific resistance of cake increases the Capillary Suction time (CST) significantly. The proper range of experimental conditions is suggested. A rapid method based on the model for estimating the averaged specific resistance of cake is proposed and compared with experimental results.
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Use of Capillary Suction apparatus for estimating the averaged specific resistance of filtration cake
Journal of Chemical Technology AND Biotechnology, 1994Co-Authors: Duu-jong Lee, Y. H. HsuAbstract:A method for estimating the averaged specific resistance of filtration cake, which avoids the necessity of measuring the liquid invasion volume in Capillary Suction apparatus (CSA) experiments, is proposed. When insufficient slurry is used, the slurry will exhaust during an experiment and the curve of wet front radius versus time shows transition. The transition point shifts according to the slurry concentration, cake specific resistance and the CSA parameters. Based on the wet front radius and the Capillary Suction time (CST) of the transition point, the liquid saturation under the inner cylinder can be estimated and the averaged specific resistance of cake calculated without the liquid invasion volume data. The proposed method agrees well with vacuum filtration data.
J B A F Smeulders - One of the best experts on this subject based on the ideXlab platform.
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interpretation of filterability measured by the Capillary Suction time method
Chemical Engineering Science, 1995Co-Authors: G H Meeten, J B A F SmeuldersAbstract:The Capillary Suction time (CST) method for measuring the filterability of a suspension is described, and its mode of operation is reviewed and discussed. A radial Capillary Suction time apparatus, and the filter paper used by it, are investigated in various ways to obtain the Capillary Suction pressure P, the water porosity ϵ of the filter paper, and the water saturation sw(r) in the filter paper as a function of the radial distance r from the suspension to be filtered. Air is shown to coexist with water in the wetted filter paper, but P and the effective water porosity are shown to be practically constant in the paper as used in the CST method. Measurements are made of the desorptivity S of a bentonite suspension using a conventional constant-pressure filter press, and compared with S obtained from CST measurements.
D. E. Smiles - One of the best experts on this subject based on the ideXlab platform.
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Water flow in filter paper and Capillary Suction time
Chemical Engineering Science, 1998Co-Authors: D. E. SmilesAbstract:Flow of water in Whatman 17 chromatography paper and the interpretation of the Capillary Suction time method for determining filterability of suspensions is examined. Filter paper water flow is described by well-established theory of water flow in porous media. This theory is based on material balance for the water and Darcy's law. Assuming that the matric potential or Suction (arising from the interaction of water with the solid surfaces and their geometry) and the hydraulic conductivity of both the filter paper and the suspension are well-defined functions of the water content, one-dimensional Capillary Suction time is analysed from considerations of material balance and continuity of water potential on the paper/suspension interface. Experiments agree with theory and illustrate that flow in the paper is unsaturated, with the advance of a wetting front in paper a function of the interaction of the sorptivity-matric potential functions of both the paper and the suspension. Extension of the approach to radial flow in the filter paper is too complicated to permit simple interpretation of wetting front advance. The Capillary Suction time method must remain a useful empirical tool for practicing engineers. Its weaknesses should be recognised, however, and constant pressure filtration tests, for example, which provide both sorptivity-, and equilibrium water content-pressure relations simply and accurately must ultimately be preferable.
