A feasibility study on capping bauxite residue coastal disposal areas with dredged material /
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1993.
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| Subjects: | |
| Online Access: | ProQuest, Abstract Link to OAKTrust copy |
| Abstract: | An environmentally-sound and economically efficient method for capping bauxite residue disposal sites using coastal dredged material is developed in this dissertation. The methodology is comprised of two stages: (i) laboratory experiments, and (ii) computer modeling. The bauxite residue-dredged material interface studied fall into three categories, namely, geotextiles, six-inch sand layer, and direct contact between bauxite residue and dredged material. The results presented include a comprehensive analysis of the effect of different variables on the salt migration between bauxite residue and dredged material layers. Twelve laboratory cylinder tests were set up to study the effect of numerous variables involved on the salt-transport process. Geochemical analysis indicated that irrespective of the nature of the interface, pore fluid in the dredged material has a tendency to dilute the alkalinity of the bauxite residue. But, in some cases with no interface between the bauxite and dredged material, there was a noticeable zone of mixing near the interface due to splashing of the dredged material during placement in the cylinder. The alkalinity values in the dredged material seemed to be little affected by the salt-transport process. It can be concluded from these results that the dredged material serves as a good capping material for the disposal site. A two-dimensional linear boundary element model was written in Fortran as part of this dissertation research. Three capping alternatives were investigated with the total number of nodes on the boundary varying between 28 and 113, and the total number of internal nodes varying between 24 and 121. A total of nineteen runs were executed to include different variables such as interface type, watertable position, dredged material depth, amount of water on top, number of nodes, and order of gauss quadrature. The model results indicate that all three types of interfaces studied could be successfully used in capping the disposal site. However, placement of dredged material would probably be more efficient on a layer of sand or geotextile. The model results showed good agreement with the analytical and experimental results. |
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| Item Description: | Vita. "Major subject: Ocean Engineering." |
| Physical Description: | xix, 180 leaves : illustrations ; 28 cm |
| Bibliography: | Includes bibliographical references. |