Liners for Waste Containment Facilities - Environmental Geomechanics - page 491

types of pollutants; improving the efficiency of the drainage bottom system; and for
delaying direct contact between the mineral liner and the leachate, thereby reducing
potential compatibility problems in some cases. Some of these aspects are only
qualitatively estimated; further research is necessary for a quantitative assessment.
− GCLs, integrated with an attenuation layer can be considered a possible
alternative to CCLs in composite liners. Careful comparison must be carried out
between the two alternatives on a case-by-case basis. The actual boundary
conditions in the time and space domains, different pollutant transport phenomena,
contaminant lifespan and active service life of the composite barrier materials and
other landfill components must be taken into account.
In order to comply with the performance design approach, landfill proposals
must provide an evaluation of environmental impact and related risk analysis
including the theoretical models of barrier behavior. The use of theoretical models
must be based on reliable input parameters, such as the field-scale hydraulic
conductivity, compatibility with the pollutants to be contained, desiccation potential,
sorption capacity, diffusion coefficients and service life. All these features of
different types of barriers have been discussed and, in particular for some,
indications for correct laboratory test procedures and appropriate interpretation
algorithms have been illustrated.
16.10. Bilbliography
[BEN 94a] B ENSON C.H., D ANIEL D.E., “Minimum thickness of compacted soil liners: I.
Stochastic models”, Journal of Geotechnical Engineering , vol. 120, no. 1, 1994, pp. 129-
152.
[BEN 94b] B ENSON C.H., D ANIEL D.E., “Minimum thickness of compacted soil liners: II.
Analysis and case histories”, Journal of Geotechnical Engineering , vol. 120 no. 1, 1994,
pp.153-172.
[BEN 94c] B ENSON C.H., H ARDIANTO F.S., M OTAN E.S., “Representative specimen size for
hydraulic conductivity assessment of compacted soil liners”, Hydraulic Conductivity and
Waste Contaminant Transport in Soil, ASTM STP, no. 1142 , Philadelphia, 1994, pp. 3-29.
[BOU 00] B OUAZZA A., V ANGPAISAL T., “Gas advective flux of partially saturated
geosynthetic clay liners”, Advances in Transportation and Geoenvironmental Systems
using Geosynthetics , Geotechnical Speciality Publication no. 103 , 2000, pp. 54-67.
[BOU 01] B OUAZZA A., K AVAZANJIAN E. J R ., “Construction on former landfills”, Proceedings
2 nd ANZ Conference on Environmental Geotechnics , Newcastle, Australia, November
2001, pp. 467-482.