Hydraulic behaviour of a geosynthetic clay liner in three wastewater lagoons

Abstract

Three wastewater lagoons were lined thanks to a geosynthetic clay liner (GCL) containing natural sodium bentonite confined thanks to argilo-calcarous soil containing silex. Leaks were detected as soon as water was introduced into the ponds. The various explanations are puncturing and weakness of the confining layer. The study performed showed that the hydraulic conductivity and swelling index of the bentonite evolved at the contact of the calcareous soil. This phenomenon itself allows explaining the rate of leakage obtained. Nonetheless, the use of soils containing puncturing elements is not consistent with the state of the art and has to be forbidden.