Bentonite/municipal solid waste leachate interactions in barriers.

摘要

This thesis examines the physical and chemical properties of commercial bentonite and assesses bentonite behaviour and compatibility with municipal solid waste leachate in slurry walls and sand-bentonite liners. The permeability/compatibility testing was performed in a fixed-ring, constant flow permeameter.;The characterization of five commercial bentonites showed a content of 50-90% smectite of montmorillonite type. The d-spacing of montmorillonite in the bentonite was found to result from the combined effect of the ESP, the specific surface, the surface charge density, the salt and carbonate content, and the pH.;The compatibility of Hydrogel bentonite slurries of initial void ratios ranging from 3.5 to 12 with domestic waste leachate of salinities ranging from 0.7 to 30.0 g/L was examined. Increases in hydraulic conductivity upon leachate permeation, k;The k-values of slurries permeated by the intermediate salinity leachates resulted from changes in pore water salinity.;Permeation with very saline leachate produced only increases in k either at constant void ratio or under decreasing void ratio.;Water compacted sand/bentonite mixtures containing 5 and 10% Avonseal bentonite were permeated directly with MSW leachate.;Leachate permeated sand-sodium bentonite mixtures exhibited early breakthrough of the contaminants particularly in samples compacted dry-of-optimum and with a low bentonite content. (Abstract shortened by UMI.).