scholarly journals Unsaturated Performance Comparison of Compacted Clay Landfill Liners

2000 ◽  
Author(s):  
Carol J. Miller ◽  
Saad Merayyan ◽  
Nazli Yesiller
Keyword(s):  
Performance Comparison ◽  
Compacted Clay ◽  
Landfill Liners

scholarly journals Interactions of Per- and Polyfluoralkyl Substances (PFAS) with Landfill Liners

2020 ◽  
Vol 1 (4) ◽  
Author(s):  
Will P Gates ◽  
◽  
Alastair JN MacLeod ◽  
Andras Fehervari ◽  
Abdelmalek Bouazza ◽  
...  
Keyword(s):  
Environmental Pollutants ◽  
Water Soluble ◽  
Compacted Clay ◽  
Geosynthetic Clay Liners ◽  
Clay Liners ◽  
Landfill Liner ◽  
Landfill Liners ◽  
Polyfluoroalkyl Substances ◽  
Published Research ◽  
Persistent Environmental Pollutants

This review synthesises the available published research on interactions of per- and polyfluoroalkyl substances (PFAS) with landfill liners, with the view to inform on the expected behaviour of these persistent environmental pollutants in landfills. The review addresses the nature and significant types of PFAS compounds that are destined for landfills, as well as their by-product. It discusses the known and anticipated interactions with separate landfill liner components, namely geomembranes, geosynthetic clay liners and compacted clay liners. Various water-soluble PFAS are shown to advectively transport through geosynthetic clay liners (GCL) and showcase the limitations of relying on mineral liners alone to retain PFAS. Addition of activated carbon, while increasing saturated hydraulic conductivity, significantly increases PFAS retention by the GCL and reduced PFAS flux to manageable concentrations. An assessment of the relative risk for environmental exposure of different types of PFAS from landfills through interaction with those liner components is achieved with reference to published case studies of PFAS detection in and around landfills from Australia and around the World.

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

Assessment of alternative protection layers for a geomembrane – geosynthetic clay liner (GM–GCL) composite liner

2008 ◽  
Vol 45 (11) ◽  
pp. 1594-1610 ◽  
Author(s):  
S. Dickinson ◽  
R. W.I. Brachman
Keyword(s):  
Tensile Force ◽  
Thick Layer ◽  
Compacted Clay ◽  
Physical Damage ◽  
Vertical Pressure ◽  
Geosynthetic Clay Liner ◽  
Landfill Liners ◽  
Clay Liner ◽  
Tire Shreds ◽  
Protection Systems

A protection layer is required above geomembrane (GM) – geosynthetic clay liner (GCL) landfill liners to limit physical damage (GM strains and GCL thinning) from an overlying granular drainage layer. A 150 mm thick layer of sand has been found to provide excellent protection at a vertical pressure of 250 kPa. However, the use of sand may not be practical in many cases. Experimental results are presented where the effectiveness of alternate protection systems above one particular GM–GCL liner were examined with 50 mm coarse gravel at an applied vertical pressure of 250 kPa. A 150 mm thick layer of compacted clay and a 150 mm thick layer of rubber tire shreds with a nonwoven needle-punched geotextile (570 g/m2) were found to limit the geomembrane strains and GCL extrusion to acceptable levels. Layered geotextiles performed much better than single layers of geotextiles. A layered geocomposite, with a thick nonwoven needle-punched geotextile in the middle to provide cushioning and stiffer woven geotextiles on the top and bottom to carry tensile force, was able to limit the short term strain to less than 3%, but it was not able to prevent local thinning of the GCL because of the deformation required to mobilize force in the geotextiles.

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