Hydraulic properties of dune sand–bentonite mixtures of insulation barriers for hazardous waste facilities

Gueddouda, Mohamed Kamel; Goual, Idriss; Benabed, Benchaa; Taïbi, Saïd; Abou-Bekr, Nabil

doi:10.1016/j.jrmge.2016.02.003

Cited by 39 publications

(11 citation statements)

References 31 publications

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“…His evaluation on the effect of pH, contact time, and contaminant concentration led to the discovery of the fact that the removal efficiencies of hydrocarbons (diesel) are 67-90% and 75-99.3% for modified activated carbon and modified bentonite, respectively. Guddada [10] stated that not only the minimum bentonite required in the reduction of hydraulic conductivity is at least 12%, but also he also believed that the saturated hydraulic conductivity of the mixture of sand and bentonite reduces with the increase in bentonite content. In this study, the best result of permeability was obtained for a sample with 15% bentonite and 85% sand.…”

Section: Introductionmentioning

confidence: 99%

Improving the permeability and adsorption of phenol by organophilic clay in clay liners

Heidarzadeh

Parhizi

2019

Environmental Engineering Research

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The aim of this study is to investigate the effect of five different combinations including: sand 70%, bentonite 30% (S70B30)-sand 80%, bentonite 20% (S80B20)-sand 80%, organophilic 20% (S80M20)-sand 60%, bentonite 20%, organophilic 20% (S60B20M20) and sand 75% -bentonite 15% -organophilic 10% (S75B15M10) on landfill linear structure in order to decrease phenol leaching. Hydraulic conductivity and adsorption behavior of the samples were investigated. The results demonstrated that the lowest hydraulic conductivity coefficient (1.16 ×       ) was obtained for S70B30. Furthermore, adding more than 20% of bentonite had no significant effect on reducing permeability. Moreover, Freundlich isotherm was introduced as the best model explaining adsorption behaviour due to its highest determination coefficient (0.945). The best samples for adsorption capacity of phenol and for both permeability and adsorption are S80M20 and S60B20M20, respectively. Although the presence of bentonite was effective in reducing hydraulic conductivity, organic clay had no considerable impact on reducing permeability. Though, it's an exceptional role in adsorbing organic contaminants including phenol cannot be ignored. To meet all regulatory constraints, the optimal compound is made up of 10.2% of bentonite and 2.8% of organophilic clays with a minimized cost of 13.64 ($/ton).

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Section: Introductionmentioning

confidence: 99%

Improving the permeability and adsorption of phenol by organophilic clay in clay liners

Heidarzadeh

Parhizi

2019

Environmental Engineering Research

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“…Such sand-bentonite mixture can be used as barrier/liner material in several engineering applications including landfill, slurry cutoff For engineering purposes, it is important to determine the swelling bentonite content that is required to achieve sufficiently low hydraulic conductivity below the typical regulatory requirement (1 × 10 −7 cm/s) [7,[59][60][61]. Such sand-bentonite mixture can be used as barrier/liner material in several engineering applications including landfill, slurry cutoff walls, and radioactive waste disposal [7][8][9][61][62][63][64]. According to the results in Figure 8d, the low K limit is achieved at bentonite percentage of 5%.…”

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confidence: 99%

“…Moreover, an important advantage of the current model is that it is applicable for wide range of binary mixed soils covering different particle sizes and fines types. It is a "unified" model that takes into account variable factors including: Developing an accurate packing model can assist several real life applications such as (a) calculating the primary volume, porosity and permeability of deposited unconsolidated sediments when modeling sedimentary basins [65][66][67], (b) optimizing concrete and aggregates mixing design to achieve a desirable porosity and hydraulic conductivity values [13][14][15]18,19], and (c) designing liners and cut off walls [7][8][9]23,61,62]. For example, the fines fraction as well as the endmembers properties required to achieve a target hydraulic conductivity can be predicted.…”

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confidence: 99%

Unified Packing Model for Improved Prediction of Porosity and Hydraulic Conductivity of Binary Mixed Soils

El-Husseiny

2021

Water

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Binary mixed soils, containing coarse sand particles mixed with variable content of fines (fine sand, silt, or clay) are important for several environmental and engineering applications. The packing state (or porosity) of such sand-fines mixtures controls several important physical properties such as hydraulic conductivity. Therefore, developing an analytical packing model to predict porosity of binary mixed soils, based on properties of pure unmixed sand and fines (endmembers), can contribute to predicting hydraulic conductivity for the mixtures without the need for extensive laboratory measurements. Toward this goal, this study presents a unified packing model for the purpose of predicting the porosity and hydraulic conductivity of binary mixed soils as function of fines fraction. The current model modifies an existing packing model developed for coarse binary mixed soils to achieve three main improvements: (1) being inclusive of wide range of binary mixed soils covering the whole range particle sizes, (2) incorporating the impact of cohesive packing behavior of the fines on binary mixture porosity, and (3) accounting for the impact of clay swelling. The presented model is the first of its kind incorporating the combined impact of all three factors: particle size ratio, fines cohesive packing and swelling, on binary mixtures porosity. The predictions of the modified model are validated using experimental published data for the porosity of sand-fines mixtures from 24 different studies. The model shows significant improvement in predicting porosity compared to existing packing models that frequently underestimate the porosity. By using the predicted porosity as an input in Kozeny–Carman formulation, the absolute mean error in predicting hydraulic conductivity, as function of fines fraction for 16 different binary mixed soils, is reduced by 50% when compared to the use of the previous packing model. The current model provides insights about the endmembers properties (porosity, hydraulic conductivity, and grain size) and fines content required to achieve a certain target desirable porosity and hydraulic conductivity of the mixed soils. This can assist the optimization of soil mixing design for various applications.

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“…Bentonite is a naturally occurring clay with high swelling capacity and low permeability due to over 75% percent of the material being made up of the clay mineral montmorillonite (Egloffstein, 2001). Bentonite content in most containment applications is between 5% and 15% of mixture (Gueddouda et al, 2016). When using these mixtures with bentonite as a barrier, it is important to maintain stability of the material when they come in contact with water and that the swelling potential of the material ensures contact with the under lying rock and that cracks existing or developing cracks will be self-filling.…”

Section: Soil Barriermentioning

confidence: 99%

“…When using these mixtures with bentonite as a barrier, it is important to maintain stability of the material when they come in contact with water and that the swelling potential of the material ensures contact with the under lying rock and that cracks existing or developing cracks will be self-filling. It is also good design practice for the mixtures to be a uniform grain size distribution to prevent bentonite leaching and decreasing the performance of the cap (Gueddouda et al, 2016).…”

Section: Soil Barriermentioning

confidence: 99%

Pilot Testing of a Geomorphic Landform Design Reclamation Using a Vegetative Layer with Short Paper Fiber Amendment on an Abandoned Coal Refuse Pile in Appalachia

Cyphers¹

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Pilot testing of a Geomorphic Landform Design reclamation using a vegetative layer with short paper fiber amendment on an abandoned coal refuse pile in Appalachia Levi J. Cyphers Over 3,000 abandoned mine lands in the Appalachian regions of West Virginia, Pennsylvania, and Kentucky and are in need of reclamation. This research tested an alternative cap and cover reclamation design using short paper fiber as a soil amendment in a coarse coal refuse vegetation layer. Short paper fiber is the solid residuals extracted from the paper manufacturing process, and treated as waste. Short paper fiber is a nutrient dense material that has been successfully tested as a soil amendment in soils. The intent of the vegetation layer was to support grass growth and persistence, stabilize the site, and reduce acid mine drainage (AMD). First, a 0.28 acre field site was designed to demonstrate and test geomorphic reclamation features in Appalachia. The field site was composed of three test plots (60% refuse with 40% paper fiber, 80% refuse with 20% paper fiber, 100% refuse) that centrally drained into a geomorphic channel. A hydraulic barrier composed of compacted refuse and slopes up to 2H:1V were included. Construction was completed September 2017 and the site was monitored (i.e. vegetation ground cover, infiltration of vegetation layer and hydraulic barrier, compaction, surface runoff water quality, and surface temperature). The constructability of the site was also studied to identify suitable construction methods during the final reclamation of the full site. Vegetation ground cover reached a maximum of 29.4% in the plot with 20% paper fiber. Infiltration of the refuse was reduced 30.5% in the hydraulic barrier of the plots containing paper fiber from the in situ material, despite not meeting the 95% required compaction density. Surface temperature varied 11°C across the plots, affecting grass germination. Though a longer duration of monitoring is needed, preliminary findings show that the mixture ratio containing 20% short paper fiber outperformed the mixture ratio containing 40% paper fiber. Reducing short paper fiber for the growth layer means additional savings in the cost of the final reclamation. I would like to take a second to show thanks for the support I have received while completing this master's program. I am appreciative of the help Dr. Leslie Hopkinson, Dr. John Quaranta, and Dr. Seung Ho Hong for the research advising received while serving on my committee. To Iuri, for his help in many days of data collection and hours spent driving, and willingness to help out in any way. To Justin and Russell, for endless advice and assistance on any task. To my family, who provided encouragement when needed, and always made sure I never went without. Thank you to Nathan Parks and Jeff Johnson, and the rest of the WVDEP for providing this opportunity for research, and their cooperation throughout the duration of this project. v

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Hydraulic properties of dune sand–bentonite mixtures of insulation barriers for hazardous waste facilities

Cited by 39 publications

References 31 publications

Improving the permeability and adsorption of phenol by organophilic clay in clay liners

Improving the permeability and adsorption of phenol by organophilic clay in clay liners

Unified Packing Model for Improved Prediction of Porosity and Hydraulic Conductivity of Binary Mixed Soils

Pilot Testing of a Geomorphic Landform Design Reclamation Using a Vegetative Layer with Short Paper Fiber Amendment on an Abandoned Coal Refuse Pile in Appalachia

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