Hydraulic conductivity study of compacted clay soils used as landfill liners for an acidic waste

2013 ◽  
Vol 33 (1) ◽  
pp. 60-66 ◽  
Author(s):  
Noureddine Hamdi ◽  
Ezzeddine Srasra
Keyword(s):  
Hydraulic Conductivity ◽  
Clay Soils ◽  
Compacted Clay ◽  
Landfill Liners

scholarly journals Hydraulic and Swell–Shrink Characteristics of Clay and Recycled Zeolite Mixtures for Liner Construction in Sustainable Waste Landfill

2021 ◽  
Vol 13 (13) ◽  
pp. 7301
Author(s):  
Marcin K. Widomski ◽  
Anna Musz-Pomorska ◽  
Wojciech Franus
Keyword(s):  
Hydraulic Conductivity ◽  
Exchange Capacity ◽  
Saturated Hydraulic Conductivity ◽  
Clay Soils ◽  
Compacted Clay ◽  
Clay Liner ◽  
Compacted Clay Liner ◽  
Drying And Rewetting ◽  
Swelling Characteristics ◽  
Shrinkage And Swelling

This paper presents research considering hydraulic as well as swelling and shrinkage characteristics of potential recycled fine particle materials for compacted clay liner for sustainable landfills. Five locally available clay soils mixed with 10% (by mass) of NaP1 recycled zeolite were tested. The performed analysis was based on determined plasticity, cation exchange capacity, coefficient of saturated hydraulic conductivity after compaction, several shrinkage and swelling characteristics as well as, finally, saturated hydraulic conductivity after three cycles of drying and rewetting of tested specimens and the reference samples. The obtained results showed that addition of zeolite to clay soils allowed reduction in their saturated hydraulic conductivity to meet the required threshold (≤1 × 10−9 m/s) of sealing capabilities for compacted clay liner. On the other hand, an increase in plasticity, swelling, and in several cases in shrinkage, of the clay–zeolite mixture was observed. Finally, none of the tested mixtures was able to sustain its sealing capabilities after three cycles of drying and rewetting. Thus, the studied clayey soils mixed with sustainable recycled zeolite were assessed as promising materials for compacted liner construction. However, the liner should be operated carefully to avoid extensive dissication and cracking.

The role of organic attenuation in saturated clay barrier system

1996 ◽  
Vol 33 (8) ◽  
pp. 145-151 ◽  
Author(s):  
Irene M. C. Lo
Keyword(s):  
Hydraulic Conductivity ◽  
Concentration Gradient ◽  
Organic Contaminants ◽  
Molecular Diffusion ◽  
Pollution Prevention ◽  
Fickian Diffusion ◽  
Compacted Clay ◽  
Landfill Liner ◽  
Landfill Liners ◽  
Saturated Clay

A review of literature finds that advection, diffusion, and retardation are the main processes that govern the migration of organic contaminants through compacted clay landfill liners. However, much emphasis is placed on the hydraulic conductivity in the specification for landfill liner design. It is misunderstood that if the hydraulic conductivity of the clay is low, then the liner must provide an adequate barrier for groundwater pollution prevention. Unfortunately, even the advection is minimal, contaminants can migrate through clay by simple Fickian diffusion at a rate that can be significant. The process of diffusion is mainly dependent on the concentration gradient between the leachate and the groundwater. If a clay lining system is installed, the only way to reduce the effect of diffusion is to reduce the concentration gradient by pollutant retardation. In this paper, the relative importance of molecular diffusion and advection, and the effect of pollutant retardation on the advective and diffusive transport are discussed using a conceptual-mathematical model. Based on a review of organic contaminant attenuation by clay liners, a guideline on the development of a high organic attenuation engineered barrier as a second line of defence for containment sites is proposed.

Statistical analyses of compacted clay landfill liners. Part 1: model development

1994 ◽  
Vol 21 (5) ◽  
pp. 872-882 ◽  
Author(s):  
Scott B. Donald ◽  
Edward A. McBean
Keyword(s):  
Hydraulic Conductivity ◽  
Geometric Mean ◽  
Model Development ◽  
Statistical Analyses ◽  
Compacted Clay ◽  
Clay Liners ◽  
Landfill Liner ◽  
Landfill Liners ◽  
Clay Liner ◽  
Spatial Correlation Structure

The acceptance of compacted clay liners, from a management point of view, has been a source of major concern because of the uncertainty associated with the hydrogeologic properties of the clay. By examining the flux of leachate through the compacted clay liner of a typical engineered landfill, where the hydraulic conductivity of the clay is represented by a stochastic process, an acceptance protocol suitable for compacted clay landfill liners is derived. Determination of the equivalent hydraulic conductivity of the clay liner is accomplished by comparing the flux of leachate through a homogeneous representation of the clay with the flux obtained by Monte Carlo analyses. Acceptance criteria are subsequently developed based on a statistical technique which calculates the confidence limits about a percentile of a probability distribution as well as about the mean of the distribution. For the landfill configuration simulated, the results indicate that the hydraulic conductivity of a compacted clay landfill liner follows a lognormal distribution and exhibits virtually no spatial correlation structure. In addition, for liners exhibiting a geometric mean conductivity of 10−7 cm/s and a standard deviation of 0.3, the geometric mean value is a conservative estimate of the hydraulic conductivity of the clay, provided the liner is constructed in a series of four 150 mm lifts. Key words: clay liners, hydraulic conductivity, statistical analyses, latin hypercube, equivalent hydraulic conductivity.

scholarly journals Clays of Different Plasticity as Materials for Landfill Liners in Rural Systems of Sustainable Waste Management

2018 ◽  
Vol 10 (7) ◽  
pp. 2489 ◽  
Author(s):  
Marcin Widomski ◽  
Witol Stępniewski ◽  
Anna Musz-Pomorska
Keyword(s):  
Hydraulic Conductivity ◽  
Environmental Sustainability ◽  
Arable Land ◽  
Saturated Hydraulic Conductivity ◽  
Compacted Clay ◽  
Landfill Liners ◽  
Environmental Threats ◽  
Waste Landfill ◽  
Drying And Rewetting ◽  
Basic Characteristics

This paper presents a study assessing the possible application of seven clay substrates of various particle compositions and plasticity, sampled locally in rural regions, as materials allowing affordable construction of the waste landfill liners, which meet the main principles of sustainability, utilize locally available materials and limit the environmental threats posed by landfill leachate to water, public health and arable land. The researched substrates were tested according to their long-term sealing properties by their saturated hydraulic conductivity after compaction, swelling and shrinkage characteristics and ability to sustain their sealing capability after repeated drying and rewetting. The basic characteristics of soils were determined by the standard methods. Saturated hydraulic conductivity after compaction and after repeated shrinking and swelling were tested in laboratory falling head permeameters. Shrinkage characteristics were based on dimensionless indicators of the geometry and linear extensibility. The obtained results showed that the tested clay substrates were found applicable to construction of compacted clay liner for sustainable waste landfill. The environmental sustainability of a local, rural waste landfill, isolated by compacted earthen liners utilizing local materials is, in our opinion possible, but strongly related to the compaction parameters applied during liner construction for the given clay substrate.

The influence of amendments on the volumetric shrinkage and integrity of compacted clay soils used in landfill liners

1996 ◽  
Vol 86 (1-4) ◽  
pp. 263-274 ◽  
Author(s):  
G. H. Omidi ◽  
T. V. Prasad ◽  
J. C. Thomas ◽  
K. W. Brown
Keyword(s):  
Clay Soils ◽  
Volumetric Shrinkage ◽  
Compacted Clay ◽  
Landfill Liners

The relationship between aggregation and other soil properties in cracking clay soils

Soil Research ◽  
1984 ◽  
Vol 22 (1) ◽  
pp. 59 ◽  
Author(s):  
KJ Coughlan ◽  
RJ Loch
Keyword(s):  
Hydraulic Conductivity ◽  
Salt Content ◽  
Chemical Properties ◽  
Aggregate Size ◽  
Strong Relationship ◽  
Clay Soils ◽  
Coarse Surface ◽  
Seedbed Preparation ◽  
The Relationship ◽  
Dispersion Ratio

This paper explores the processes responsible for clay dispersion, and the formation of large dry aggregates, in cracking clay soils. It also isolates the soil factors causing variations in dry aggregate size using regression analysis. Twelve cracking clay soil samples were selected on visual differences in dry aggregate size distribution following seedbed preparation, and a range of soil structural and chemical properties were measured. The per cent dry aggregates > 5 mm was found to increase with resistance to mechanical abrasion, stability to wet sieving after capillary wetting, and dispersion ratio, indicating that large dry aggregates are formed as a result of binding by dispersed clay. Both raindrop impact and puddling by cultivation may be involved in dispersion. There was a strong relationship between dry aggregate size in the 0-10 cm layer and salt content in the subsurface (60-90 cm) layer. Coarse surface aggregation is explained in terms of limited profile hydraulic conductivity. For the soils studied, the properties of the surface layer appear to be responsible, at least in part, for the limitation in profile hydraulic conductivity. Dry aggregate size in the 0-10 cm layer was not simply correlated with any of the chemical properties of that layer. However, equations containing two (ESP and CEC per gram of clay) or three (ESP, per cent clay and CEC) independent variables were derived to explain variations in dry aggregate size, both for the 12 soils studied and for a wider range of Queensland cracking clay soils.

scholarly journals Effect of Ammonium on the Hydraulic Conductivity of Kaolin and Bentonite as Clay Liners

2020 ◽  
Vol 4 (2) ◽  
pp. 100-111
Author(s):  
Adebola Adebayo Adekunle ◽  
Igba Uvieoghene Tobit ◽  
Ogunrinola Oluwaseyi Gbemiga
Keyword(s):  
Hydraulic Conductivity ◽  
Ground Water ◽  
Tap Water ◽  
Bentonite Clay ◽  
Research Paper ◽  
Low Permeability ◽  
Main Function ◽  
Clay Liners ◽  
Landfill Liners ◽  
Different Sources

: Landfill liners are underlying materials with low permeability whose main function is to mitigate the infiltration of toxic contents into ground water lying beneath. Landfill liners are primarily made of bentonite clay. Bentonite has a very low hydraulic conductivity, that might not be readily accessible, unlike kaolin which is found to have a lower hydraulic conductivity compared to that of bentonite and can be extensively obtained from numerous different sources. Explored, for the purposes of the present research paper, were various ratios of bentonite and kaolin and their hydraulic conductivity, in particular ratios of 90:10 kaolin to bentonite, 80:20 kaolin to bentonite, 70:30 kaolin to bentonite, 60:40 kaolin to bentonite and 50:50 kaolin to bentonite in an effort to achieve an acceptable barrier suitable as a liner / where tap water and ammonium solution were used as permeants. It was concluded that the ratios not lower than 20% bentonite (80:20, 70:30, 60:40 and 50:50) all had their hydraulic conductivity value reduced compared to the 100% kaolin.

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