Effect of multiple contaminant migration on diffusion and adsorption of some domestic waste contaminants in a natural clayey soil

1989 ◽  
Vol 26 (2) ◽  
pp. 189-198 ◽  
Author(s):  
F. S. Barone ◽  
E. K. Yanful ◽  
R. M. Quigley ◽  
R. K. Rowe

This paper describes laboratory model tests involving the placement of domestic landfill leachate on top of a layer of saturated undisturbed clayey soil and allowing chemical constituents to migrate into the soil by diffusion only. During the testing period (15 days), samples from the overlying leachate were regularly collected and analyzed for the chemical constituents of interest (i.e., Cl−, Na+, K+, Mg++, and Ca++). At the end of the test, the soil layer was sectioned to determine the pore-water and adsorbed concentration variations with depth for each species. Mathematical model POLLUTE was then used to back-figure both the diffusion coefficient (D) and the adsorption term (ρK). The measured diffusion coefficients at a temperature of 10 °C were determined to be [Formula: see text], [Formula: see text], and [Formula: see text]. The corresponding adsorption terms were [Formula: see text], [Formula: see text], and [Formula: see text].Ca++ and Mg++, originally predominant on the clay exchange sites, were heavily desorbed to accommodate the adsorption of migrating Na+, K+, and possibly NH4+, causing hardness halo effects that the model could not fit. This behaviour corresponds to that commonly observed at domestic waste sites in southern Ontario.The importance of multiple contaminant migration on diffusion rates was assessed by comparing the leachate models with similar models using a variety of single salts dissolved in distilled water as the source solutions. For the single-salt models, all species considered, including Ca++ and Mg++, behaved in a way that could be described by conventional Fickian theory. A comparison of the diffusion and adsorption parameters obtained from the two types of models indicated that for both Na+ and K+, the measured D and ρK from the leachate models were 20 and 60% lower, respectively, than the values obtained from the single-salt models. For Cl−, the diffusion coefficient obtained from the leachate models was 25% higher than that obtained from the single-salt models.For the Sarnia grey soil used, both D and ρK are significantly influenced by the types and amounts of co-diffusing species present in the initial source solutions. Laboratory tests conducted to determine diffusion parameters for use in design should be run with soils and source solutions chemically identical to those expected in the field. Key words: domestic waste leachate, multiple contaminant migration, clayey soil, diffusion, adsorption, laboratory study.

1995 ◽  
Vol 32 (7) ◽  
pp. 215-219 ◽  
Author(s):  
Magdelinka Radenkova-Yaneva ◽  
Emilia Kostakeva ◽  
Dimiter Toshev

It is well known that the leachates from solid domestic waste sanitary landfills are heavily polluted with organic and inorganic substances. As they are of a potential danger for the environment, their uncontrolled seepage is avoided in the modern sanitary landfills by means of suitable insulation. This is mostly made of natural materials with a low filtration coefficient. The present paper considers the results of the filtration characteristics, studying natural clayey soil model liners. The leachate contaminants distribution from the sanitary landfill in Sofia (Suhodol) is traced out in different liner depths. The mechanism of pollutant attenuation in the liners is considered. It is found that a part of the leachate components (Fe, Mn, SO42−, PO43−) stays in clayey liners. Besides, as a result of pore colmatation the permeability of the liners is decreased. It is shown that soil monoliths with a proper thickness might serve as a sufficiently safe barrier against leachate filtration in adjacent aquifers. On the base of the results obtained the thickness of the clay liners in the solid domestic waste sanitary landfills could be optimized.


1988 ◽  
Vol 25 (1) ◽  
pp. 108-118 ◽  
Author(s):  
R. Kerry Rowe ◽  
Chris J. Caers ◽  
Frank Barone

This paper describes a technique for determining the diffusion coefficient and the distribution coefficient for contaminants using saturated, intact (undisturbed) clayey soil samples. The technique is illustrated with reference to a number of laboratory tests involving advective-diffusive migration of potential contaminants through an intact clayey soil from Sarnia, Ontario. An important aspect of the proposed technique is that the mass of contaminant in the system is kept constant and so significant decrease in source leachate concentration occurs during each test. A simple theoretical model is used to analyze this case and it is shown that this phenomenon can be used to deduce both the diffusion coefficient and the distribution/partitioning coefficient from a single test. Parameters are deduced for a number of salt solutions passing through the clay from the Sarnia area. On the basis of these tests it is suggested that for the Sarnia soil and advective velocities up to the maximum examined (0.035 m/a), mechanical dispersion does not measurably affect the magnitude of the "coefficient of hydrodynamic dispersion" (i.e., there is no significant dispersion). It is also suggested that the effective porosity corresponds to that deduced from the water content of the soil. Key words: contaminant migration, soil, laboratory study, experimental, analysis, diffusion, advection, clays, groundwater.


2020 ◽  
Vol 857 ◽  
pp. 283-291
Author(s):  
Safa Hussain Abid Awn ◽  
Jasim M. Abbas

Soft clayey soils cover wide Iraqi areas specially the regions close to rivers and the southern part of this country Heavy weight structures like: highways, dams, multiple story buildings are suffering unacceptable settlement, when constructing on soft soils. The high contamination of water in such soils decrease the effective stress and reduce bearing capacity. The need was appeared to improve such problematic soil by the use of new technique of stone column treated with different percentages of natural bentonite by a series of field tests using full scale concrete footing constructed on soft soil in addition to a laboratory model to investigate settlement with time at constant stress. The soil that used in this study is natural clayey soil, brought from a location south of Diyala governorate, from a farm area. The study includes also: The effect of stone column diameter treated with bentonite on the behavior of footing constructing on soft clayey soil, The effect of stone column length on the behavior of footing on such soils. Results of field and laboratory model tests reviled that the treated model by stone column mixed with 40% bentonite is the ideal one, which reduces the settlement by 55%. In other hand problems of uneven settlements appear when using 60% bentonite as a mix proportion. The Ideal slenderness ratio (Ds/Ls<25%). The effective depth of stone column treated with bentonite is (1/3H).


Author(s):  
Braja M. Das ◽  
Kim H. Khing ◽  
Eun C. Shin

The load-bearing capacity of a weak clay subgrade can be increased by placing a strong granular base course of limited thickness on top of the clay layer. The load-bearing capacity can be increased further, or the thickness of the granular base course can be reduced, by separating both layers by a geogrid. Laboratory model test results for the ultimate bearing capacity of a rigid strip loading on the surface of a granular soil underlain by a soft clay with a layer of geogrid at the interface of the two soils are presented. The optimum thickness of the granular soil layer and the critical width of the geogrid layer required to derive the maximum benefit from the reinforcement were determined. Model test results on the permanent settlement of the rigid strip load caused by cyclic loading of low frequency are presented.


2016 ◽  
Vol 845 ◽  
pp. 70-75
Author(s):  
Yusep Muslih Purwana ◽  
Niken Silmi Surjandari ◽  
Haryanto Wahyu

Jack-in piling is environmental friendly system enabling placement of the pile into soil layer with minimum disturbance. It works with very low noise, low vibration, allows piling in confined area, relatively very fast in term of installation rate, better quality control and very fast in mobility. The main issue regarding the pile is bearing capacity; the ability of the pile to withstand axial load without failure. This study attempts to find the correlation between jack-in force and ultimate pile bearing capacity. The result of 5 piling record on clayey layer soil indicates that there is a good correlation between jack-in force and empirical ultimate pile bearing capacity.


2017 ◽  
Vol 4 (2) ◽  
Author(s):  
JOY K DEY ◽  
LALA IP RAY ◽  
Y. MARWEIN

Availability of in-situ soil water plays a major role in exploiting the potential yield of crops under irrigated conditions. Depending on type of irrigation, variations of soil water is mostly observed at different soil depths within the root zone. The deviation of soil water at the edaphic zone becomes a deciding factor in assuring optimum yield. As availability of irrigation water is a great concern during non-rainy season, water saving irrigation techniques need to be adopted to maximize the productivity under hilly terrain. An experiment was laid out with potato as a test crop under the valley region of Meghalaya plateau on sandy clayey soil to study in-situ soil water dynamics under three different irrigation methods viz. furrow, micro-sprinkler and gravity-fed drip. Irrigation was scheduled at every weekly basis to restore back the soil water required to achieve the field capacity. Mean value of soil water up to 15 cm depth was 21.75, 22.65 and 23.45%, however, range (minimum to maximum) was 16.21-29.17; 15.56-29.21 and 17.84-28.97% for furrow, micro-sprinkler and gravity-fed drip irrigation, respectively. Co-efficient of variation was found to be the maximum (4.65%) for furrow over other two types of irrigations during the weekly interval. Deviation of in-situ soil water was found to vary rapidly at upper layer (30 cm) under furrow method of irrigation; but at deeper soil layer rapid variation was not observed. Water use efficiency of potato was evaluated to be 14.66, 18.78, 20.63 kg ha-1 mm-1 for furrow, micro-sprinkler and gravity-fed drip irrigation, respectively.


2016 ◽  
Vol 6 (1) ◽  
pp. 917-922 ◽  
Author(s):  
M. O. Karkush

The behavior of single piles driven into contaminated clayey soil samples subjected to a combination of static axial and cyclic lateral loadings have been studied in this research. A laboratory model was manufactured especially for studying such behavior. A solid circular cross sectional area pile of diameter 19 mm and made from aluminum, the pile was embedded into the soil with an eccentricity to embedded length (e/L) ratio of 0.334. The intact soil samples and industrial wastewater were obtained from the center of Iraq. The industrial wastewater is a byproduct disposed from Musayib thermal electric power plant. The intact clayey soil samples were synthetically contaminated with four percentages of 10, 20, 40 and 100% from the weight of water used in the soaking process which continued for a period of 30 days. The different percentages of contaminant concentrations have significant effects on the lateral load-displacement relation of the piles subjected to a combination of axial and lateral loadings. The vertical displacement under the same vertical load increased by 5–95%, the axial strength of piles decreased by 10–34% and the lateral-bearing capacity of the piles decreased by 10–34% with increasing the percentage of contamination from 10 to 100%. The ratio of permanent lateral displacement to the total lateral displacement was increased by 23–27% when the concentration of contaminant increased by 10-100%. Generally, the application of axial loading increases the lateral-bearing capacity of piles, and reduces the total lateral displacement.


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