Thesis
HYDRAULIC AND MECHANICAL BEHAVIOR OF AN ELECTROCHEMICALLY REMEDIATED CLAYEY SOIL
Washington State University
Master of Science (MS), Washington State University
01/2021
DOI:
https://doi.org/10.7273/000005490
Handle:
https://hdl.handle.net/2376/119198
Abstract
Electrochemical (EC) method has shown promising tendencies as an alternative to excavation and off-site disposal for in-situ treatment of inorganic contaminated fine-grained soils. However, the post hydro-mechanical behavior of the treated soil is not fully known. In this study, laboratory-scale reactor experiments resemblant of a field-scale EC system were conducted on soil samples collected from two borehole locations from a rights-of-way site in Illinois, reported to be contaminated with arsenic (As) and manganese (Mn) that violates their maximum allowable concentration (MAC). Using a combination of hydrogen peroxide (H2O2) and/or citrate buffer as treatment solutions, the reactor experiments were carried out for a duration of 28, 17 and 14 days, while applying a low intensity electrical field to compacted soil samples. Treatment using 10% H2O2 and citrate buffer solution had an average removal of 23% and 8% for Mn and As. For the second reactor experiment where 4% H2O2 and citrate buffer was used, 39% (for Mn) and 24% (for As) removal efficiency were achieved; while using only citrate buffer as the treatment solution for the third reactor experiment, 49% (for Mn) and 9% (for As) extraction were achieved. All chemical regimes adopted in this study reduced the concentration of As and Mn to below their MAC for use as fill material in Illinois as specified by the United States Environmental Protection Agency (USEPA). Results from geotechnical analyses demonstrated that the treatment process has effects on the hydraulic, mechanical, and overall physiochemical properties of the soil. These changes occurred owing to the reactions, including pH gradient and redox reactions that occurred within the EC system. Furthermore, the plasticity (1%, 117% increase and 32% reduction for experiment 1, 2 and 3 respectively), strength (6%, 26% reduction and 100% increase for experiment 1, 2 and 3 respectively) and water retention behavior of the treated soil exhibited several phenomena when varied with residual concentration of As and Mn. The findings from this study indicates that EC treatment has considerable effects on the post hydromechanical behavior of soils, and thus, becomes imperative for proper evaluation and care when adopted in the field.
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Details
- Title
- HYDRAULIC AND MECHANICAL BEHAVIOR OF AN ELECTROCHEMICALLY REMEDIATED CLAYEY SOIL
- Creators
- Taiwo Olawale Akinleye
- Contributors
- Idil D Akin (Advisor)Balasingam Muhunthan (Committee Member)Amanda K Hohner (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Civil and Environmental Engineering
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Number of pages
- 149
- Identifiers
- 99900592260901842
- Language
- English
- Resource Type
- Thesis