Fully transient analytical solution for degradable organic contaminant transport through GMB/GCL/AL composite liners

Feng, Shi‐Jin; Peng, Ming-Qing; Chen, Hongxin; Chen, Zhang‐Long

doi:10.1016/j.geotexmem.2019.01.017

Cited by 27 publications

(29 citation statements)

References 44 publications

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“…The physical properties incorporate diffusion, advection, and dispersion [15][16] . The chemical process includes sorption, dissolution, complexation, hydrolysis/substitution and oxidation [17][18][19] . To predict the leaching of chlorides, zinc, iron, lead, and copper numerical parameters engaged with governing set of equations that depict the model processes should be accurately characterized.…”

Section: Materials and Testing Methodologymentioning

confidence: 99%

“…The initial condition of the liner system can then be expressed as (Chen et al 16 ; Xie et al 9 ; Feng et al 18 , 19 ): …”

Section: Methodsmentioning

confidence: 99%

“…The thickness of the liner is an essential deciding factor since it determines the strength and permeability. Till date, many researchers studied the use of analytical [15][16][17][18][19] and numerical approaches 20 for contamination transport (mainly organic) and to determine the liner thickness. However, the analytical methods are timing consuming and difficult for solving non-linear and differential equations 20 .…”

mentioning

confidence: 99%

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Modelling contaminant transport in fly ash–bentonite composite landfill liner: mechanism of different types of ions

Garg

Reddy

Huang

et al. 2020

Sci Rep

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Generated hazardous or toxic waste posses a serious threat if dumped into ponds or low lying areas which leads to contamination, this necessitates the effective landfill liner system. Mainly compacted clayey soils are used as an engineered barrier. Recently, composite materials have gained popularity as landfill liner materials, including the use of waste materials amended with low permeable soils. Though, studies on the composite optimum mix and its corresponding thickness are very scarce. Here, we evaluated the unconfined compressive strength and hydraulic conductivity of fly ash-bentonite composites. Efforts were also made to determine the thickness of landfill liner composite using a finite difference method (i.e. MATLAB). The results reveal that composite consists of 30% bentonite and 70% fly ash is suitable for landfill liner, which meets strength and permeability criteria. Numerical simulation for five major contaminants shows that the composite plays a crucial role in reducing the leaching of heavy metals and suggests an optimum thickness in the range of 126-154 cm. Overall, the findings of the study indicate that fly ash-bentonite composite can be used to solve real-life challenges in a sustainable way. Landfill liner is a low-permeable barrier, which acts as a partition between the waste and its surrounding environment. Well constructed landfills are more secure than open dumping 1. The fundamental factor influencing the nature of compacted clay liners is their low permeabilities, which should be as less as 1.0 × 10-7 cm/s suggested by RCRA (Subtitle D). To avoid contamination of groundwater (due to permeation of leachate), generally clayey soils are compacted to achieve desired permeability. Sand-bentonite composites are also used as engineered barriers or liners to prevent leaching of contaminants 2. Other than hydraulic conductivity, strength also needs to be considered in assessing landfill liner material. Earlier studies and environmental guidelines proposed a minimum unconfined compressive strength (UCS) of 0.20 MPa to utilize as a landfill liner material 3. Few studies reported that waste-bentonite composites satisfy the strength criteria when a correct mix proportion used 3,4. The utilization of wastes like fly ash solves the problems associated with waste management and also saves the extensive exploitation of natural materials 5,6. Fly ash and bentonite can replace the sand-bentonite liners because of lack of available natural sand and an increase in the cost, which is widely used in other construction activities. Fly ash is known for its pozzolanic reactions, and that solidifies and gains strength over time when cured. Therefore, the curing period prompts an increase in strength and reduction of hydraulic conductivity. Recent studies have examined the amendment of fly ash to the soil, found the enhanced geotechnical properties such as cation exchange capacity, shear strength, and hydraulic conductivity 3,7,8. Problems in landfill lining system of a waste containment facilities can be escalate...

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Section: Materials and Testing Methodologymentioning

confidence: 99%

“…The initial condition of the liner system can then be expressed as (Chen et al 16 ; Xie et al 9 ; Feng et al 18 , 19 ): …”

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Modelling contaminant transport in fly ash–bentonite composite landfill liner: mechanism of different types of ions

Garg

Reddy

Huang

et al. 2020

Sci Rep

View full text Add to dashboard Cite

show abstract

“…Analytical solutions are very important for understanding many scientific phenomena (e.g., solute transport, heat transfer, water flow and deformation problems), 1,2,23,24,27,29–31 even though simplifications should be made to derive them. Especially, analytical solutions play a unique role in verifying many new numerical methods 32–34 .…”

Section: Introductionmentioning

confidence: 99%

“…Liner system is an important part of modern municipal solid waste (MSW) landfill to control the generated leachates and protect its surrounding environment (e.g., groundwater and surface water) from the hazardous contaminant 1–3 . A composite liner system consisting of a geomembrane layer (GMBL), a compacted clay liner (CCL) and an attenuation layer (AL) is widely used in the modern MSW landfills 3 .…”

Section: Introductionmentioning

confidence: 99%

Analytical solution for one‐dimensional steady‐state contaminant transport through a geomembrane layer (GMBL)/compacted clay layer (CCL)/attenuation layer (AL) composite liner considering consolidation

Yan

Xie

Ding

et al. 2022

Num Anal Meth Geomechanics

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A composite liner system consisting of a geomembrane layer (GMBL), a compacted clay layer (CCL) and an attenuation layer (AL) is widely used in the modern landfills. The field and experimental observations highlight the potential detrimental effects on breakthrough of contaminants induced by consolidation of soil liner when a relatively high applied stress is caused by the waste placement. A one dimensional steady‐state model is developed to investigate the behaviour of contaminant transport in GMBL/CCL/AL composite liner system considering consolidation. Effects of the consolidation process on the transport of typical contaminants are investigated by the proposed analytical solution. The analytical results show that the magnitude of volume compressibility coefficient in the AL is important in controlling the overall magnitude of the consolidation induced effects. The process of consolidation shows a larger impact on the absorbable pollutants compared to the non‐absorbable pollutants. This may be due to the fact that the migration of solid particles induced by the consolidation may assist the transport of contaminant absorbed on them. The thickness of the AL shows large impacts on the bottom flux for the case with a high volume compressible coefficient. Increasing the thickness of AL from 1 to 3 m can results in a factor of 2.6 increase of the bottom flux. Increasing the thickness of the AL leads to a larger consolidation advection and a longer consolidation path, which may be the dominant mechanisms for contaminant transport compared to the diffusion process.

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Semi‐analytical solution for the two‐dimensional transport of organic contaminant through geomembrane with strip defects to the underlying soil liner

Sun

Peng

et al. 2022

Num Anal Meth Geomechanics

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Geosynthetic materials are widely adopted as part of barrier liners in landfills, while the existence of defects in geomembrane (GM) will significantly reduce the barrier efficiency and lead to unexpected pollution in the surrounding environment. In this study, a novel semi-analytical model was proposed to investigate the two-dimensional (2D) migration of organic contaminant through the GM with strip defects to the underlying soil liner (SL). This model has the superiority to consider the concentration condition in the defects, and describe more accurate concentration profiles in the SL. The combination of discretization method and integral transforms were applied to obtain semi-analytical solutions, which were then verified by numerical solutions. Results show that the existence of defects can substantially accelerate the migration process of contaminant through flawed GM to the underlying SL. Specifically, the time interval between migration curves in the model with defects can be 2 or 3 orders of magnitude shorter than that without defects under the same condition.

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Fully transient analytical solution for degradable organic contaminant transport through GMB/GCL/AL composite liners

Cited by 27 publications

References 44 publications

Modelling contaminant transport in fly ash–bentonite composite landfill liner: mechanism of different types of ions

Modelling contaminant transport in fly ash–bentonite composite landfill liner: mechanism of different types of ions

Analytical solution for one‐dimensional steady‐state contaminant transport through a geomembrane layer (GMBL)/compacted clay layer (CCL)/attenuation layer (AL) composite liner considering consolidation

Semi‐analytical solution for the two‐dimensional transport of organic contaminant through geomembrane with strip defects to the underlying soil liner

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