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 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.

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 use of Ankara Clay as a compacted clay liner for landfill sites

Clay Minerals ◽  
2017 ◽  
Vol 52 (3) ◽  
pp. 391-412 ◽  
Author(s):  
H. Akgün ◽  
A.G. Türkmenoğlu ◽  
İ. Met ◽  
G.P. Yal ◽  
M.K. Koçkar
Keyword(s):  
Hydraulic Conductivity ◽  
Liquid Limit ◽  
Plasticity Index ◽  
Dry Density ◽  
Compacted Clay ◽  
Maximum Dry Density ◽  
Liner Material ◽  
Landfill Liner ◽  
Ankara Clay ◽  
Landfill Sites

AbstractBecause of the current need for new landfill sites in Ankara, the suitability of Ankara Clay as a liner material for landfill sites was investigated. A mineralogical and geotechnical database was created by compiling the results of previous tests by the present authors as well as those of tests performed in the present study. The mineralogical properties of the samples were investigated by X-ray diffraction, scanning electron microscopy and methylene blue adsorption. The cation exchange capacities (CEC) of the samples vary from 12 to 35 meq/100 g soil and the dominant clay minerals are illite, smectite and kaolinite. The geotechnical properties of the Ankara Clay samples that were assessed included specific gravity, the Atterberg limits (plastic limit, liquid limit, plasticity index), particle-size distribution, compaction properties (i.e.maximum dry density and optimum water content) and hydraulic conductivity. Because the hydraulic conductivity of the samples was lower than the acceptable limit of 1 × 10−9 m/s, it follows that, from a geotechnical perspective, Ankara Clay is a suitable material for use as a compacted clay landfill liner. The relationships between the mineralogical and geotechnical parameters that were investigated by regression analysis indicated that the hydraulic conductivity of the compacted soil samples decreased with increasing plasticity index, clay content, CEC, smectite content, smectite to illite ratio and decreasing illite content. According to the specifications for field construction of compacted clay liners, Ankara Clay is suitable for compaction in the field.

HYDRAULIC CONSIDERATIONS FOR LANDFILL LINERS AND THE CHARACTERISTICS OF SOILBENTONITE MIX = Pertimbangan Hidrolik untuk Liners Landfill dan Karakteristik Campuran Tanah-Bentonit

2016 ◽  
Vol 14 (1) ◽  
pp. 25
Author(s):  
Alfakhur Ridlo ◽  
Masami Ohtsubo
Keyword(s):  
Hydraulic Conductivity ◽  
Void Ratio ◽  
Chemical Properties ◽  
Physical Structure ◽  
Hydraulic Performance ◽  
Design Parameters ◽  
Landfill Liner ◽  
Landfill Liners ◽  
Liner System ◽  
Successful Design

Keberhasilan desain landfill liner membutuhkan pertimbangan yang diberikan kepada unjuk kerja hydraulic liner dari landfill. Unjuk kerja sistem hydraulic liner meliputi control laju kebocoran, waktu tempuh kontaminan melewati liner, dan attenuasi (penguatan) dari spesies kontaminan leachate. Parameter seperti ketebalan, slope, permeability, metode konstruksi dan property kimia dari material liner dapat divariasikan selama proses desain untuk memaksimalkan unjuk kerja hydraulic dari landfill liner. Efek variasi setiap komponen unjuk kerja di bahas. Unjuk kerja tiga tipe liner dibandingkan. Hasil dari perbandingan untuk membahas pentingnya parameter-parameter desain dalam penentuan unjuk kerja hydraulic dari beberapa tipe liner. Selanjutnya, berbagai macam campuran tanah dan bentonite yang dibikin compact di observasi karakteristk void ratio dan hydraulic conductivity untuk mengetahui perilaku hydraulic setelah diaplikasikan tekanan terkait dengan struktur fisik. Kata kunci :hidrolika, lempung, liner, landfill, campuran tanah-bentonite Abstract The successful design of a landfill liner requires that consideration be given to the hydraulic performance of the landfill. The hydraulic performance of a landfill liner system comprises control of leakage rate, contaminant travel time through the liner and attenuation of leachate contaminant species. Parameter such as the thickness, slope, permeability, construction method and chemical properties of liner materials can be varied during design to maximize the hydraulic performance of the landfill liner. The effect of varying each of these on the components of hydraulic performance is discussed. The hydraulic performances of three common types of liner are compared. The results of the comparison are used to discuss the importance of design parameters in determining the hydraulic performance of the different types of liner. Additionally several soil-bentonite admixture were compacted and the characteristics of void ratio and hydraulic conductivity were plotted for the understanding of their hydraulic behavior after the application of pressure with respect only for physical structure. Keywords: hydraulic, clay, liner, landfill, soil-bentonite mix

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.

scholarly journals Design and construction of the barrier system for the Halton Landfill

2000 ◽  
Vol 37 (3) ◽  
pp. 662-675 ◽  
Author(s):  
R Kerry Rowe ◽  
Chris J Caers ◽  
Glenn Reynolds ◽  
Cliff Chan
Keyword(s):  
Hydraulic Conductivity ◽  
Impact Assessment ◽  
Concentration Profile ◽  
Organic Contaminants ◽  
Laboratory Experiments ◽  
Chloride Concentration ◽  
Design Concept ◽  
Good Prediction ◽  
Air Pocket ◽  
The Impact

Considerations related to the design of the Halton Landfill as a "hydraulic trap" are summarized together with the research that was conducted to support the design concept. The interrelationship between hydrogeology and the engineered design is examined. Laboratory experiments demonstrated that there can be diffusion away from a source, even with significant inward velocity. Existing theory was found to provide a good prediction of the observed concentration profile in these experiments. It is also shown that a pressurized air pocket below the clay effectively acts as a zero-flux boundary and hence, with respect to migration of chloride, could be conservatively neglected in the impact assessment. The results of the impact calculations predict only a small increase in chloride concentration in the receptor aquifer while there is negligible predicted impact due to organic contaminants. The landfill was designed and constructed with a granular "sub-liner contingency layer" (SLCL) beneath the compacted liner. The operation of this layer is discussed. Finally, the construction of the compacted clayey liner with a hydraulic conductivity of 1 × 10-8 cm/s is documented.Key words: landfill, hydraulic containment, liner, field case, construction.

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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