| Summary: | Geosynthetics are used in a wide variety of applications, including lining and
drainage of waste containment facilities. A limited amount of data were available on the
clogging potential of geonets and needed to be addressed. Using leachate from a MSW
landfill simulated realistic conditions. In addition, a hydraulic gradient and confining stress
of 0.02 and 300 kPa respectively were used as constant test parameters.
Clogging rates of 36 and 96 hours were observed with new leachate that was high
in iron. Reduced rates of clogging occurred where the leachate strength was lower. All
tests did, however, have rapid clogging (all test combinations would have clogged within
100 days). This clogged material pooled in the pores of the geonet and did not adhere
strongly to either the geonet or the geomembrane.
Differences were observed with the various combinations. Textured
geomembranes had higher rates of clogging than smooth geomembranes. High density
polyethylene did not reduce the cross sectional area of a geonet as much as low density
polyethylene. Both the transmissivity values of the geonet as well as the geonets imprint
on the geomembrane substantiated this. Geonet orientation appears to have the greatest
effect on transmissivity with those geonets having their channels oriented more in the
direction of flow having higher transmissivities. Further testing is, however, needed to
determine if geosynthetic use in leachate collection and detection systems is adequate.
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