ELECTRO-KINETIC FLOW BARRIERS IN COMPACTED CLAY
Double liner systems are now required for new hazardous waste landfills and impoundments to prevent groundwater contamination caused by leachate. However, uncertainty always exists about the longevity of the synthetic flexible membrane liner, and the compacted clay components of the liner system may release some seepage in time under a sustained hydraulic head. The mechanisms of contaminant retention by clay minerals are not fully understood, and the attenuation capacity of any containment system is finite. In addition, diffusion through the clay liner under a concentration gradient may increase the rate of contaminant migration into the environment above that owing to advection alone. Electro-kinetic counterflow may be an effective measure to stop the migration of contaminants under a hydraulc gradient. An electro-kinetic fluid flow barrier can be created by the continuous or periodic application of an electrical gradient across a compacted clay liner. A coupled flow theory to describe the simultaneous flows of water, electricity, and contaminant ions under the influences of hydraulic, electrical, and chemical gradients has been developed by using the formalism of the thermodynamics of irreversible processes. An experimental testing program demonstrated the existence of electro-osmotic flow in partly saturated compacted clay and provided a basis to evaluate the validity of the theoretical predictions. An electrical gradient may move some inorganic species in soils much more effectively than hydraulic gradient. An electro-kinetic flow barrier halted the migration of the cation but accelerated that of the anion under laboratory testing conditions.
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Availability:
- Find a library where document is available. Order URL: http://worldcat.org/isbn/0309050642
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Supplemental Notes:
- This paper appears in Transportation Research Record No. 1288, Geotechnical Engineering 1990. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
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Authors:
- Mitchell, James K.
- Yeung, Albert T
- Publication Date: 1990
Media Info
- Features: Figures; References; Tables;
- Pagination: p. 1-9
- Monograph Title: Geotechnical engineering 1990 - soils, geology and foundations
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Serial:
- Transportation Research Record
- Issue Number: 1288
- Publisher: Transportation Research Board
- ISSN: 0361-1981
Subject/Index Terms
- TRT Terms: Compacted clays; Contaminants; Electrical equipment; Electrokinetics; Electroosmosis; Flow; Groundwater; Hydraulic gradient; Laboratory tests; Landfills; Leachate; Thermodynamics
- Uncontrolled Terms: Contamination; Membranes
- Old TRIS Terms: Electric gradient; Electroosmotic flow; Flow barriers; Membranes (Biology); Test results
- Subject Areas: Geotechnology; Highways; I42: Soil Mechanics;
Filing Info
- Accession Number: 00607744
- Record Type: Publication
- ISBN: 0309050642
- Files: TRIS, TRB
- Created Date: Apr 30 1991 12:00AM