Transport of Organic Contaminants in Composite Vertical Cut-Off Wall with Defective HDPE Geomembrane
Soil-bentonite vertical cut-off wall is an emergency technique used for contaminant control in geo-environmental engineering, high-density polyethylene (HDPE) geomembrane (GM) with an extremely low-permeability coefficient is expected to enhance the contaminant barrier effect of the vertical cut-off...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-07-01
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| Series: | Polymers |
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| Online Access: | https://www.mdpi.com/2073-4360/15/14/3031 |
| _version_ | 1797587670552018944 |
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| author | Hai Lin Wenzhou Huang Liangni Wang Zhanlei Liu |
| author_facet | Hai Lin Wenzhou Huang Liangni Wang Zhanlei Liu |
| author_sort | Hai Lin |
| collection | DOAJ |
| description | Soil-bentonite vertical cut-off wall is an emergency technique used for contaminant control in geo-environmental engineering, high-density polyethylene (HDPE) geomembrane (GM) with an extremely low-permeability coefficient is expected to enhance the contaminant barrier effect of the vertical cut-off wall. To evaluate the barrier performance of the composite barrier composed of GM and soil-bentonite mixture towards organic contaminant, while also quantitively revealing the impact of GM defects and placement, a one-dimensional transport model for organic contaminants in composite barrier is solved under semi-infinite boundary conditions. The proposed transport model is validated by numerical simulations using COMSOL Multiphysics 5.4, and the effects of GM defect rate, placement within the composite isolation wall, and contact level with soil-bentonite on contaminant transport behavior are further studied. The results show that as the average frequency of GM defects increases from 2.5 to 50 holes per hectare, the breakthrough time of organic contaminants through composite barrier decreases by almost 70%. Poor contact level between GM and soil-bentonite mixture may reduce the breakthrough time of the composite cut-off wall by 65%. Although the selection of GM placement has limited impact on the transient flux of contaminants, it does affect the total flux of contaminants over a certain period of time. The effects of permeability coefficient, effective diffusion coefficient, distribution coefficient, and hydraulic head of the composite cut-off wall can be considered by the proposed analytical solution, which would provide guidance and reference for the design and service performance evaluation of the composite cut-off wall. |
| first_indexed | 2024-03-11T00:43:09Z |
| format | Article |
| id | doaj.art-9740ba58f5bd4096be238bfc769cde5b |
| institution | Directory Open Access Journal |
| issn | 2073-4360 |
| language | English |
| last_indexed | 2024-03-11T00:43:09Z |
| publishDate | 2023-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Polymers |
| spelling | doaj.art-9740ba58f5bd4096be238bfc769cde5b2023-11-18T21:02:21ZengMDPI AGPolymers2073-43602023-07-011514303110.3390/polym15143031Transport of Organic Contaminants in Composite Vertical Cut-Off Wall with Defective HDPE GeomembraneHai Lin0Wenzhou Huang1Liangni Wang2Zhanlei Liu3School of Infrastructure Engineering, Nanchang University, Nanchang 330031, ChinaSchool of Infrastructure Engineering, Nanchang University, Nanchang 330031, ChinaSchool of Infrastructure Engineering, Nanchang University, Nanchang 330031, ChinaKey Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing 210024, ChinaSoil-bentonite vertical cut-off wall is an emergency technique used for contaminant control in geo-environmental engineering, high-density polyethylene (HDPE) geomembrane (GM) with an extremely low-permeability coefficient is expected to enhance the contaminant barrier effect of the vertical cut-off wall. To evaluate the barrier performance of the composite barrier composed of GM and soil-bentonite mixture towards organic contaminant, while also quantitively revealing the impact of GM defects and placement, a one-dimensional transport model for organic contaminants in composite barrier is solved under semi-infinite boundary conditions. The proposed transport model is validated by numerical simulations using COMSOL Multiphysics 5.4, and the effects of GM defect rate, placement within the composite isolation wall, and contact level with soil-bentonite on contaminant transport behavior are further studied. The results show that as the average frequency of GM defects increases from 2.5 to 50 holes per hectare, the breakthrough time of organic contaminants through composite barrier decreases by almost 70%. Poor contact level between GM and soil-bentonite mixture may reduce the breakthrough time of the composite cut-off wall by 65%. Although the selection of GM placement has limited impact on the transient flux of contaminants, it does affect the total flux of contaminants over a certain period of time. The effects of permeability coefficient, effective diffusion coefficient, distribution coefficient, and hydraulic head of the composite cut-off wall can be considered by the proposed analytical solution, which would provide guidance and reference for the design and service performance evaluation of the composite cut-off wall.https://www.mdpi.com/2073-4360/15/14/3031vertical cut-off walldefect of geomembraneorganic contaminantsthe migration behavior of contaminantsanalytical solution |
| spellingShingle | Hai Lin Wenzhou Huang Liangni Wang Zhanlei Liu Transport of Organic Contaminants in Composite Vertical Cut-Off Wall with Defective HDPE Geomembrane Polymers vertical cut-off wall defect of geomembrane organic contaminants the migration behavior of contaminants analytical solution |
| title | Transport of Organic Contaminants in Composite Vertical Cut-Off Wall with Defective HDPE Geomembrane |
| title_full | Transport of Organic Contaminants in Composite Vertical Cut-Off Wall with Defective HDPE Geomembrane |
| title_fullStr | Transport of Organic Contaminants in Composite Vertical Cut-Off Wall with Defective HDPE Geomembrane |
| title_full_unstemmed | Transport of Organic Contaminants in Composite Vertical Cut-Off Wall with Defective HDPE Geomembrane |
| title_short | Transport of Organic Contaminants in Composite Vertical Cut-Off Wall with Defective HDPE Geomembrane |
| title_sort | transport of organic contaminants in composite vertical cut off wall with defective hdpe geomembrane |
| topic | vertical cut-off wall defect of geomembrane organic contaminants the migration behavior of contaminants analytical solution |
| url | https://www.mdpi.com/2073-4360/15/14/3031 |
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