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.

scholarly journals Hydraulic Conductivity of Compacted Lime-Softening Sludge Used as Landfill Liners

2019 ◽  
Vol 230 (12) ◽  
Author(s):  
Agnieszka Dąbska
Keyword(s):  
Hydraulic Conductivity ◽  
Moisture Content ◽  
Tap Water ◽  
Distilled Water ◽  
Landfill Liners ◽  
Water Permeation ◽  
Lime Softening ◽  
Approximate Polynomial ◽  
Hazardous Waste Landfills

AbstractThe research goal was to investigate the hydraulic conductivity of compacted lime-softening sludge as a material to be applied to landfill liners. In doing so, the effect of compaction and moulding moisture content on the sludge hydraulic conductivity was assessed. An approximate polynomial k10mean at hydraulic gradients ≥30 for degree of compaction (0.95–1.05) and moulding moisture content (28%–36%) was determined. The results of short-term tap water permeation tests revealed that all hydraulic conductivity values were less than 2.5•10–8 m/s. A lowest hydraulic conductivity of 6.5•10–9 m/s, as well as a corresponding moisture content of 31% were then established. The long-term hydraulic conductivity was measured with tap water, distilled water, NaOH and HCl solutions and municipal waste leachate. The factors of permeating liquids and permeation time significantly affected the initial hydraulic conductivity. The long-term hydraulic conductivity increased for NaOH and HCl solutions and decreased for tap and distilled water. A significant reduction of hydraulic conductivity was observed for leachate permeation. The investigated material met the requirements for the liner systems of inert landfill sites regardless of pH and the limit value for hazardous and non-hazardous waste landfills.

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.

Effect of incineration ash leachates on the hydraulic conductivity of bentonite-polymer composite geosynthetic clay liners

2022 ◽  
Vol 139 ◽  
pp. 25-38
Author(s):  
Christian Wireko ◽  
Tarek Abichou ◽  
Kuo Tian ◽  
Binte Zainab ◽  
Zhiming Zhang
Keyword(s):  
Hydraulic Conductivity ◽  
Polymer Composite ◽  
Geosynthetic Clay Liners ◽  
Clay Liners

scholarly journals Heavy metal levels in drinking water sources of Chingola District, Zambia

2020 ◽  
Author(s):  
Francis Hamwiinga ◽  
Chisala D. Meki ◽  
Patricia Mubita ◽  
Hikabasa Halwiindi
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Drinking Water ◽  
Ground Water ◽  
Water Samples ◽  
Tap Water ◽  
Water Sources ◽  
Wet Season ◽  
Drinking Water Sources ◽  
Metal Levels

Abstract Background: One of the factors impeding access to safe water is water pollution. Of particular concern is heavy metal contamination of water bodies. This study was aimed at determining the levels of heavy metals in drinking water sources of Chingola District of Zambia. Methods: A cross sectional study was employed. A total of 60 water samples were collected. Thirsty (30) samples were collected in the dry season in the month of October 2016 and another 30 in the wet season in the months of February and March, 2017. For each season 10 water samples were collected from each of the three water sources. i.e. Tap water, Urban ground water sources and Rural ground water sources. Heavy metal analysis was done using Atomic Absorption Spectrophotometer (AAS).Results: This study revealed that the concentrations of Iron, Manganese, Lead, Nickel and Arsenic were beyond maximum permissible levels in various water sources. Combined averages for both dry and wet seasons were as follows: Iron: 2.3, Copper: 0.63, Cobalt: 0.02, Manganese: 0.36, Lead: 0.04, Zinc:3.2, Nickel: 0.03, Arsenic: 0.05. Chromium and Cadmium were below detection limit in all water samples. The median concentrations of iron, arsenic, copper, manganese in drinking water from the Tap, rural and urban ground water sources were different, and this difference was statistically significant (p<0.05). The median concentrations of arsenic, nickel, manganese and cobalt were different between dry and wet season, and this difference was statistically significant (p<0.05).Conclusions: Sources of heavy metals in water seems to be both natural and from human activities. The concentration of heavy metals in different water sources in this study was found to be above the recommended levels. This calls for improvement in water monitoring to protect the health of the public. Therefore, there is need for continuous monitoring of heavy metals in drinking water sources by regulatory authorities.

scholarly journals An Estimation Model for Hydraulic Conductivity of Low-Permeability and Unfilled Fractured Granite in Underground Water-Sealed Storage Caverns

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Yangbing Cao ◽  
Weiguo Gong ◽  
Xiangxiang Zhang ◽  
Junxi Chen ◽  
Zhenping Huang
Keyword(s):  
Hydraulic Conductivity ◽  
Water Pressure ◽  
Underground Structure ◽  
Underground Water ◽  
Stress Index ◽  
Low Permeability ◽  
Proposed Model ◽  
Imaging Results ◽  
Water Conduction ◽  
Fractured Granite

The permeability of rock mass is closely related to the stability and safety of underground structure, especially in underground water-sealed storage caverns. With regard to the estimation approaches in predicting the hydraulic conductivity of fractured granite in water-sealed storage caverns, there are some limitations of parameter selection leading to poor applicability. Focusing on the contribution of the water conduction fractures (WCF) to the hydraulic conductivity, we attempted to propose a novel model, the CA model, for estimating its hydraulic conductivity based on the fracture orientation index and the normal stress index by analyzing the borehole wall imaging results and borehole water-pressure test results in the site of underground water-sealed storage caverns. The results indicated that the proposed model is suitable for low-permeability and unfilled fractured granite, exhibiting good effectiveness by clarifying the relation between geomechanical parameters and hydraulic behavior. Further, the parameters upon which the proposed model is based are representative and easy to obtain, which has certain guiding significance and reference value for analyzing the permeability characteristics of similar rock masses.

scholarly journals Correlations between physico-chemical properties and nickel adsorption parameters in soils used in sanitary landfill liners

2020 ◽  
Vol 34 (3) ◽  
pp. 275-284
Author(s):  
Ricardo Antonio Ferreira da Silva ◽  
Danilo Brito da Costa ◽  
William de Paiva ◽  
Márcio Camargo de Melo ◽  
Veruschka Escarião Dessoles Monteiro
Keyword(s):  
Chemical Properties ◽  
Bentonite Clay ◽  
Exchange Capacity ◽  
Isotherm Models ◽  
Sanitary Landfill ◽  
Adsorption Parameters ◽  
Clayey Sand ◽  
Landfill Liners ◽  
Physico Chemical ◽  
Nickel Adsorption

The adsorption of heavy metals by sanitary landfill liners represents a measure of protection of surface and groundwaters against contamination by metals, mitigating risks to public health. Hence, this research aimed to identify, from correlations, the influence of physico-chemical properties of soils applied in landfill liners using nickel adsorption parameters. Batch equilibrium tests with initial nickel concentrations of 45 to 1440 mg.L-1 were performed in clayey sand and bentonite clay soil, as well as in mixtures. Nickel adsorption parameters from Freundlich and Langmuir isotherm models were obtained, exhibiting a better adjustment in the Freundlich model based on R² and RMSE criteria. Thus, the addition of bentonite clay improved the adsorption to nickel, and the cationic exchange capacity (CEC) was the property that considerably influenced the metal retention in the studied soils.

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