Parameter Determination for Chloride and Tritium Transport in Undisturbed Lysimeters during Steady Flow

Abstract Marginal sediments can be used to combat punctual pollution by heavy metals in industrial zones. Such practice requires information on metal-concentration in the workshop discharge water. Knowledge about the reaction of the heavy metal with the sediment available in the landscape is of utmost importance. Modeling of batch experiments and breakthrough curves, BTC, supplies relevant information in this regard. We modeled the static batch-data by Freundlich isotherms for testing CdCl2 aqueous solutions equilibria with sandy loam sediment and the dynamic column-data by two codes, CfitM and CfitIM, under saturated water flow conditions. Three Cd-concentrations (5, 20, and 40 ppm) were employed to investigate the conjunction of using two procedures for obtaining the pertinent parameters for the transport of such a heavy metal and the design of the adequate Cd-trap. The results showed the deviations of the two techniques due to differences in their theoretical concepts, mathematical formulation, and performance. The batch method showed utility in supplying first guesses for the retardation factor, R, to insert into the 4-parameter analytical code, CfitIM, applied for column BTC modeling. The iteratively-obtained-parameters of the Freundlich equation were then employed to generate the distribution coefficient, k d. The generated value was, in turn, used to get more fair guess for the retardation factor, R, to use as a fixed-value in the CfitIM code to get an in-depth insight into the BTC dynamics and to obtain the other pertinent model parameters. The BTC runs indicated that the concentration controls the distinctive adsorption and transport rate and behavior of the heavy metal in the sediment column. The most dilute solution offered the highest Cd impediment, as shown by the most significant values for the distribution coefficient, k d, and retardation factor, R. The malfunction of the sediment as a trap appeared at Cd-concentrations four to eight folds higher than the most dilute solution. However, the loamy sand trap is successful when fed with a dilute aqueous solution. A set of successive traps is to arrange in tandem lines when moderate to high concentration is to discharge from an industrial workshop. The results emphasize the utility of the mutual use of these two lab procedures for the design of adequate traps and landfills and the simulation of more complex situations in the field. The point-pollution control needs to continue running batch and BTC experiments and to carry out their corresponding modeling.

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Functioning of the multilinear lag-cascade flood routing model as a means of transporting pollutants in the river

Water Science & Technology Water Supply ◽

10.2166/ws.2020.181 ◽

2020 ◽

Vol 20 (7) ◽

pp. 2845-2857

Author(s):

Jafar Chabokpour ◽

Barkha Chaplot ◽

Mehdi Dasineh ◽

Amir Ghaderi ◽

Hazi Md Azamathulla

Keyword(s):

Residence Time ◽

Delay Time ◽

Transport Model ◽

Breakthrough Curves ◽

Flood Routing ◽

Velocity Variation ◽

Model Parameters ◽

Length Unit ◽

Advection Dispersion ◽

Complete Study

Abstract The purpose of this paper is to use the application of the multilinear lag cascade model as a contaminant transport model through river networks. Monocacy River and Antietam Creek data, which were collected by USGS with different reach lengths and discharge conditions, have been used in the current study. It was found that the multilinear discrete lag-cascade (MDLC) model is capable of reconstructing contaminant breakthrough curves. A complete study was performed to estimate the reach length for use in the accurate simulation, and it was concluded that by assuming a uniform flow through the reach, the length unit should be obtained by applying Pe = 12. Moreover, by using temporal moment matching, explicit relationships for MDLC model parameters (k, n, and τ) and based on conventional advection-dispersion equation (ADE) parameters (D, u, x) were extracted. MDLC parameters of the field breakthrough curves were extracted, and it was found that the increase of Pe number caused an increase in delay time and the number of cascades. However, the residence time was obtained to be fixed. Additionally, by assuming the dispersivity parameter (D/u) is constant, the changes in the MDLC parameters were investigated by velocity variation, and new relationships were proposed to estimate the parameters under different hydraulic conditions. Using presented equations provided in this study for residence time (k), cascade number (n), and delay time (τ), the sensitivity analysis was performed, and it was found that the parameters of velocity (u), dispersion coefficient (D), and velocity (u) have the most important effect in calculation of them, respectively.

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Bayesian Parameter Determination of a CT-Test Described by a Viscoplastic-Damage Model Considering the Model Error

Metals ◽

10.3390/met10091141 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1141 ◽

Cited By ~ 1

Author(s):

Ehsan Adeli ◽

Bojana Rosić ◽

Hermann G. Matthies ◽

Sven Reinstädler ◽

Dieter Dinkler

Keyword(s):

Experimental Data ◽

Health Monitoring ◽

Measurement Errors ◽

Model Updating ◽

Surface Displacement ◽

Life Time ◽

Model Error ◽

Image Correlation ◽

Parameter Determination ◽

Model Parameters

The state of materials and accordingly the properties of structures are changing over the period of use, which may influence the reliability and quality of the structure during its life-time. Therefore identification of the model parameters of the system is a topic which has attracted attention in the content of structural health monitoring. The parameters of a constitutive model are usually identified by minimization of the difference between model response and experimental data. However, the measurement errors and differences in the specimens lead to deviations in the determined parameters. In this article, the Choboche model with a damage is used and a stochastic simulation technique is applied to generate artificial data which exhibit the same stochastic behavior as experimental data. Then the model and damage parameters are identified by applying the sequential Gauss-Markov-Kalman filter (SGMKF) approach as this method is determined as the most efficient method for time consuming finite element model updating problems among filtering and random walk approaches. The parameters identified using this Bayesian approach are compared with the true parameters in the simulation, and further, the efficiency of the identification method is discussed. The aim of this study is to observe whether the mentioned method is suitable and efficient to identify the model and damage parameters of a material model, as a highly non-linear model, for a real structural specimen using a limited surface displacement measurement vector gained by Digital Image Correlation (DIC) and to see how much information is indeed needed to estimate the parameters accurately even by considering the model error and whether this approach can also practically be used for health monitoring purposes before the occurrence of severe damage and collapse.

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Conjunctive Use of BTC and Batch Methods for Heavy Metal Transport

10.21203/rs.3.rs-53856/v3 ◽

2020 ◽

Author(s):

Mohamed Fahmy Hussein ◽

Hassan Khater

Keyword(s):

Heavy Metal ◽

Distribution Coefficient ◽

Sandy Loam ◽

Mathematical Formulation ◽

Breakthrough Curves ◽

Retardation Factor ◽

Model Parameters ◽

Dilute Solution ◽

High Concentration ◽

Point Pollution

Abstract Marginal sediments can be used to combat point-pollution by heavy metals in industrial zones. Such practice requires information on metal-concentration in the workshop discharge water. Knowledge about the reaction of the heavy metal with the sediment available in the landscape is of utmost importance. Modeling of batch experiments and breakthrough curves, BTC, supplies relevant information in this regard. We present the static batch results of Freundlich isotherms testing CdCl2 aqueous solutions equilibria with sandy loam sediments, along with column-data processed by the dynamic codes CfitM and CfitIM under saturated water flow conditions. Three Cd-concentrations (5, 20, and 40 ppm) were employed to investigate the conjunction of using two procedures for obtaining the pertinent parameters for the transport of such a heavy metal and the design of the adequate Cd-trap. The results showed the deviations of the two techniques due to differences in their theoretical concepts, mathematical formulation, and performance. The batch method showed utility in supplying first guesses for the retardation factor, R, to insert into the 4-parameter analytical code, CfitIM, applied for column BTC modeling. The iteratively-obtained-parameters of the Freundlich equation were then employed to generate the distribution coefficient, k d. The generated value was, in turn, used to get more fair guess for the retardation factor, R, to use as a fixed-value in the CfitIM code to get an in-depth insight into the BTC dynamics and to obtain the other pertinent model parameters. The BTC runs indicated that the concentration controls the distinctive adsorption and transport rate and behavior of the heavy metal in the sediment column. The most dilute solution offered the highest Cd impediment, as shown by the most significant values for the distribution coefficient, k d, and retardation factor, R. The malfunction of the sediment as a trap appeared at Cd-concentrations four to eight folds higher than the most dilute solution. However, the loamy sand trap is successful when fed with a dilute aqueous solution. A set of successive traps is to arrange in tandem lines when moderate to high concentration is to discharge from an industrial workshop. The results emphasize the utility of the mutual use of these two lab procedures for the design of adequate traps and landfills and the simulation of more complex situations in the field. The point-pollution control needs to continue running batch and BTC experiments and to carry out their corresponding modeling.

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Conjunctive Use of BTC and Batch Methods for Heavy Metal Transport

10.21203/rs.3.rs-53856/v2 ◽

2020 ◽

Author(s):

Mohamed Fahmy Hussein ◽

Hassan Khater

Keyword(s):

Heavy Metal ◽

Distribution Coefficient ◽

Sandy Loam ◽

Mathematical Formulation ◽

Breakthrough Curves ◽

Retardation Factor ◽

Model Parameters ◽

Dilute Solution ◽

High Concentration ◽

Point Pollution

Abstract Marginal sediments can be used to combat point-pollution by heavy metals in industrial zones. Such practice requires information on metal-concentration in the workshop discharge water. Knowledge about the reaction of the heavy metal with the sediment available in the landscape is of utmost importance. Modeling of batch experiments and breakthrough curves, BTC, supplies relevant information in this regard. We present the static batch results of Freundlich isotherms testing CdCl2 aqueous solutions equilibria with sandy loam sediments, along with column-data processed by the dynamic codes CfitM and CfitIM under saturated water flow conditions. Three Cd-concentrations (5, 20, and 40 ppm) were employed to investigate the conjunction of using two procedures for obtaining the pertinent parameters for the transport of such a heavy metal and the design of the adequate Cd-trap. The results showed the deviations of the two techniques due to differences in their theoretical concepts, mathematical formulation, and performance. The batch method showed utility in supplying first guesses for the retardation factor, R, to insert into the 4-parameter analytical code, CfitIM, applied for column BTC modeling. The iteratively-obtained-parameters of the Freundlich equation were then employed to generate the distribution coefficient, k d. The generated value was, in turn, used to get more fair guess for the retardation factor, R, to use as a fixed-value in the CfitIM code to get an in-depth insight into the BTC dynamics and to obtain the other pertinent model parameters. The BTC runs indicated that the concentration controls the distinctive adsorption and transport rate and behavior of the heavy metal in the sediment column. The most dilute solution offered the highest Cd impediment, as shown by the most significant values for the distribution coefficient, k d, and retardation factor, R. The malfunction of the sediment as a trap appeared at Cd-concentrations four to eight folds higher than the most dilute solution. However, the loamy sand trap is successful when fed with a dilute aqueous solution. A set of successive traps is to arrange in tandem lines when moderate to high concentration is to discharge from an industrial workshop. The results emphasize the utility of the mutual use of these two lab procedures for the design of adequate traps and landfills and the simulation of more complex situations in the field. The point-pollution control needs to continue running batch and BTC experiments and to carry out their corresponding modeling.

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Inverting stop-flow leaching experiments and detection of physical and chemical non-equilibria

10.5194/egusphere-egu2020-22395 ◽

2020 ◽

Author(s):

Lian Zhou ◽

Laurent Lassabatere ◽

Khalil Hanna

Keyword(s):

Experimental Data ◽

Breakthrough Curves ◽

Water Fraction ◽

Mobile Water ◽

Immobile Water ◽

Leaching Experiments ◽

Water Fractions ◽

Physical And Chemical ◽

Flow Experiments ◽

Stop Flow

<p>Flow heterogeneity strongly impacts mass transport. In particular, the presence of water fractionation into mobile and immobile water fractions may affect pollutant sorption to soil particles. Indeed, before sorbing, the pollutants need to diffuse from mobile water to immobile water fractions. In a previous study, we investigated the possibility of stop-flow experiments for the detection of physical and chemical non-equilibria. A sensitivity analysis proved that it was possible to detect the two types of non-equilibria. The effect of parameters related to physical&#160; (mobile water fraction and solute exchange rate)&#160; and chemical (chemical kinetics) non-equilibria were varied and related impacts on the shape of the breakthrough curves were characterized for stop-flow experiments. However, the feasibility of inverting procedures was not investigated at all. In particular, the estimation of these parameters by fitting the model to real experimental data (with noise) may be feasible but may also bring some uncertainty with biased and non-unique estimates. In this study, using both numerically generated data and experimental data, we characterize the estimate uncertainty and equifinality. This study will help in optimizing the inverting procedure for the design of more robust and less biased estimates and the quantification of physical and chemical non-equilibria parameters.</p>

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Modeling of NO3 transport in gypsiferous soil under unsaturated flow

Muthanna Journal for Agricultural Sciences ◽

10.52113/mjas04/8.3/47h ◽

2021 ◽

Vol 8 (3) ◽

Author(s):

Ramzi M. Shihab ◽

Ahmed A. Fattah ◽

Noor Aldeen M. Muhawish

Keyword(s):

Unsaturated Flow ◽

Nitrate Concentration ◽

Dispersion Model ◽

Soil Column ◽

Potassium Nitrate ◽

Breakthrough Curves ◽

Retardation Factor ◽

Soil Columns ◽

Water Head ◽

Gypsum Content

"This study was conducted to determine the effect of gypsum content and depth of water head on displacement and transport of nitrate in gypsiferous soil under unsaturated flow conditions. Also, to predict the concentration of nitrate using convection dispersion model (CDE). Soil columns with 63, 97, 142, 180, and 236 g kg-1 of gypsum were prepared. 200 mg L-1 of potassium nitrate were added to the surface of each soil column. The soil columns were leached by intermittent ponding in 2 pore volumes of water. A constant head depth of 0.005, 0.01, and 0.015 m of water was kept on the top of soil column. Samples of effluent were collected for measuring nitrate concentration. The CDE model was analyzed to estimate the best fitting between measured and predicted nitrate concentration, and to calculate dispersion coefficient (D), the retardation factor (R), and Peclet number (P). Results showed that CDE can be used to predict nitrate concentration in soil. Good fit was observed to describe breakthrough curves (BTC's), and predict the transport of nitrates in the leachate of gypsum soil columns. D values increased with the increase in the content of soil gypsum and decrease with increase the water head. Its values ranged between 6.59-9.87 m 2h-1. P and pore water velocity (v) decreased with the increase in soil gypsum content. The R values were less than 1 for all treatments"

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Transport of Microorganisms in the Underground – Processes, Experiments and Simulation Models

Water Science & Technology ◽

10.2166/wst.1991.0080 ◽

1991 ◽

Vol 24 (2) ◽

pp. 309-314 ◽

Cited By ~ 16

Author(s):

G. Teutsch ◽

K. Herbold-Paschke ◽

D. Tougianidou ◽

T. Hahn ◽

K. Botzenhart

Keyword(s):

Simulation Models ◽

Mass Conservation ◽

Breakthrough Curves ◽

Conservation Equation ◽

Retardation Factor ◽

Natural Systems ◽

Laboratory Setup ◽

Preliminary Model ◽

Sand And Gravel ◽

Mass Conservation Equation

In this paper the major processes governing the persistence and underground transport of viruses and bacteria are reviewed in respect to their importance under naturally occurring conditions. In general, the simulation of the governing processes is based on the macroscopic mass-conservation equation with the addition of some filter and/or retardation factor and a decay coefficient, representing the natural “die-off” of the microorganisms. More advanced concepts try to incorporate growth and decay coefficients together with deposition and declogging factors. At present, none of the reported concepts has been seriously validated. Due to the complexity of natural systems and the pathogenic properties of some of the microorganisms, experiments under controlled laboratory conditions are required. A laboratory setup is presented in which a great variety of natural conditions can be simulated. This comprises a set of 1 metre columns and an 8 metre stainless-steel flume with 24 sampling ports. The columns are easily filled and conditioned and therefore used to study the effects of different soil-microorganism combinations under various environmental conditions. In the artificial flume natural underground conditions are simulated using sand and gravel aquifer material from the river Neckar alluvium. A first set of results from the laboratory experiments is presented together with preliminary model simulations. The large variety of observed breakthrough curves and recovery for the bacteria and viruses under investigation demonstrates the great uncertainty encountered in microbiological risk assessment.

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Biochar caged zirconium ferrite nanocomposites for the adsorptive removal of Reactive Blue 19 dye in a batch and column reactors and conditions optimizaton

Zeitschrift für Physikalische Chemie ◽

10.1515/zpch-2020-1749 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Shazia Perveen ◽

Raziya Nadeem ◽

Shaukat Ali ◽

Yasir Jamil

Keyword(s):

Experimental Data ◽

Low Dose ◽

Fixed Bed ◽

Breakthrough Curves ◽

Adsorption Efficiency ◽

Fixed Bed Column ◽

Flow Rates ◽

Adsorptive Removal ◽

Reactive Blue 19 ◽

Pseudo Second Order

Abstract Biochar caged zirconium ferrite (BC-ZrFe2O5) nanocomposites were fabricated and their adsorption capacity for Reactive Blue 19 (RB19) dye was evaluated in a fixed-bed column and batch sorption mode. The adsorption of dye onto BC-ZrFe2O5 NCs followed pseudo-second-order kinetics (R 2 = 0.998) and among isotherms, the experimental data was best fitted to Sips model as compared to Freundlich and Langmuir isotherms models. The influence of flow-rate (3–5 mL min−1), inlet RB19 dye concentration (20–100 mg L−1) and quantity of BC-ZrFe2O5 NCs (0.5–1.5 g) on fixed-bed sorption was elucidated by Box-Behnken experimental design. The saturation times (C t /C o = 0.95) and breakthrough (C t /C o = 0.05) were higher at lower flow-rates and higher dose of BC-ZrFe2O5 NCs. The saturation times decreased, but breakthrough was increased with the initial RB19 dye concentration. The treated volume was higher at low sorbent dose and influent concentration. Fractional bed utilization (FBU) increased with RB19 dye concentration and flow rates at low dose of BC-ZrFe2O5 NCs. Yan model was fitted best to breakthrough curves data as compared to Bohart-Adams and Thomas models. Results revealed that BC-ZrFe2O5 nanocomposite has promising adsorption efficiency and could be used for the adsorption of dyes from textile effluents.

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