Modeling the effect of chloride contaminant migration on groundwater

2021 ◽  
Vol 6 (2) ◽  
Author(s):  
S. Elkholy ◽  
Mostafa Abd El-Warith ◽  
H. Guirguis ◽  
M. El-Sheikh
1977 ◽  
Vol 12 (1) ◽  
pp. 233-255
Author(s):  
J.F. Sykes ◽  
A.J. Crutcher

Abstract A two-dimensional Galerkin finite element model for flow and contaminant transport in variably saturated porous media is used to analyze the transport of chlorides from a sanitary landfill located in Southern Ontario. A representative cross-section is selected for the analysis. Predicted chloride concentrations are presented for the cross section at various horizon years.


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.


Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 683 ◽  
Author(s):  
Yukihiro Ouchi ◽  
Hiroyuki Yanagisawa ◽  
Shigehiko Fujimaki

This study describes a methodology for evaluating regulatory levels of phthalate contamination. By collecting experimental data on short-term phthalate migration using thermal desorption–gas chromatography–mass spectrometry (TD–GC–MS), the migration of di(2-ethylhexyl) phthalate (DEHP) from polyvinyl chloride (PVC) to polyethylene (PE) was found to be expressed by the Fickian approximation model, which was originally proposed for solid (PVC)/liquid (solvent) migration of phthalates. Consequently, good data correlation was obtained using the Fickian approximation model with a diffusion coefficient of 4.2 × 10−12 cm2/s for solid (PVC)/ solid (PE) migration of DEHP at 25 °C. Results showed that temporary contact with plasticized polymers under a normal, foreseeable condition may not pose an immediate risk of being contaminated by phthalates at regulatory levels. However, as phthalates are small organic molecules designed to be dispersed in a variety of polymers as plasticizers at a high compounding ratio, the risk of migration-related contamination can be high in comparison with other additives, especially under high temperatures. With these considerations in mind, the methodology for examining regulatory levels of phthalate contamination using TD–GC–MS has been successfully demonstrated from the viewpoint of its applicability to solid (PVC)/solid (PE) migration of phthalates.


Author(s):  
Wesley McCall ◽  
Thomas M. Christy ◽  
James J. Butler

Direct push (DP) methods provide a cost-effective alternative to conventional rotary drilling for investigations in unconsolidated formations. DP methods are commonly used for sampling soil gas, soil and groundwater; installing small-diameter monitoring wells; electrical logging; cone penetration testing; and standard penetration tests. Most recently, DP methods and equipment for vertical profiling of formation hydraulic conductivity (K) have been developed. Knowledge of the vertical and lateral variations in K is integral to understanding contaminant migration and, therefore, essential to designing an adequate and effective remediation system. DP-installed groundwater sampling tools may be used to access discrete intervals of the formation to conduct pneumatic slug tests. A small-diameter (38mm OD) single tube protected screen device allows the investigator to access one depth interval per advancement. Alternatively, a larger diameter (54mm OD) dual-tube groundwater profiling system may be used to access the formation at multiple depths during a single advancement. Once the appropriate tool is installed and developed, a pneumatic manifold is installed on the top of the DP rod string. The manifold includes the valving, regulator, and pressure gauge needed for pneumatic slug testing. A small-diameter pressure transducer is inserted via an airtight fitting in the pneumatic manifold, and a data-acquisition device connected to a laptop computer enables the slug test data to be acquired, displayed, and saved for analysis. Conventional data analysis methods can then be used to calculate the K value from the test data. A simple correction for tube diameter has been developed for slug tests in highly permeable aquifers. The pneumatic slug testing technique combined with DP-installed tools provides a cost-effective method for vertical profiling of K. Field comparison of this method to slug tests in conventional monitoring wells verified that this approach provides accurate K values. Use of this new approach can provide data on three-dimensional variations in hydraulic conductivity at a level of detail that has not previously been available. This will improve understanding of contaminant migration and the efficiency and quality of remedial system design, and ultimately, should lead to significant cost reductions.


Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3010
Author(s):  
Weihong Peng ◽  
Menglin Du ◽  
Feng Gao ◽  
Xuan Dong ◽  
Hongmei Cheng

Hydraulic fracturing (HF) is widely used in shale gas development, which may cause some heavy metals release from shale formations. These contaminants could transport from the fractured shale reservoirs to shallow aquifers. Thus, it is necessary to assess the impact of pollution in shallow aquifers. In this paper, a new analysis model, considering geological distributions, discrete natural fractures (NFs) and faults, is developed to analyze the migration mechanism of contaminants. Furthermore, the alkali erosion of rock caused by high-pH drilling of fluids, is considered in this paper. The numerical results suggest that both NFs and alkali erosion could reduce the time required for contaminants migrating to aquifers. When NFs and alkali erosion are both considered, the migration time will be shortened by 51 years. Alkali erosion makes the impact of NFs, on the contaminant migration, more significant. The migration time decreases with increasing pH values, while the accumulation is on the opposite side. Compared with pH 12.0, the migration time would be increased by 45 years and 29 years for pH 11.0 and 11.5, respectively. However, the migration time for pH 12.5 and 13.0 were found to be decreased by 82 years and 180 years, respectively. Alkali erosion could increase the rock permeability, and the elevated permeability would further enhance the migration velocity of the contaminants, which might play a major role in assessing the potential contamination of shallow aquifers.


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