Bentonite Liners for Isolation of Waste Disposal Sites
- 1 January 1987
- journal article
- research article
- Published by SAGE Publications in Waste Management & Research: The Journal for a Sustainable Circular Economy
- Vol. 5 (1), 93-105
- https://doi.org/10.1177/0734242x8700500113
Abstract
The applicability of bentonite as a lining material for isolation of waste disposal sites was investigated on laboratory and field scale. The permeability of sand-bentonite mixtures depends on the type of bentonite, the bentonite content in the mixture and the dry bulk density. In laboratory experiments the saturated conductivity decreased at low hydraulic head gradients, indicating that water flow in these mixtures does not obey Darcy's law. The swelling of the bentonite, which is responsible for the low permeability, is a time-dependent process. The permeability decreased with time and even after two months the permeability had not reached a constant level. In sand-bentonite mixtures with 5% (w/w) bentonite, the saturated conductivity ultimately reached a level below 1 x 10-10 m s-1, which is sufficiently low for surface capping of waste disposal sites. The sand-bentonite mixtures were 10-100 times more permeable for landfill leachate than for clean water. Bottom liners should, therefore, contain considerably more bentonite to prevent infiltration of leachate in the subsoil. Water-balance studies on experimental fields showed that there was no leakage at all through bentonite liners used for surface capping of a waste disposal site over a two-year period.Keywords
This publication has 2 references indexed in Scilit:
- Soil Compaction and Permeability Prediction ModelsJournal of Environmental Engineering, 1984
- Soil-Bentonite Slurry Trench CutoffsJournal of the Geotechnical Engineering Division, 1980