Biological clogging of geocomposites exposed to raw landfill leachate over an extended period

Considerable savings in void space could be achieved if it were possible to demonstrate the viability of geocomposites as an alternative to stone basal draining layers in landfills. Geo composites have not been used in this context because of their susceptibility to particulate and biological clogging. There is limited data available to guide designers on the use of geocomposites exposed to landfill leachate. Double column permeameters were used to model the flow rate of six geocom posites exposed to raw landfill leachate over a 7-month period. The onset of biological clogging was rapid in all cases and, in most cases, stabilised after approximately 70 days. The equilibrium value for overall discharge/time of discharge ranged from 17 to 39% of the mitial value. The potential eco nomic and environmental benefits of a reliable alternative to stone drainage blankets justify further investigation to vali date and extend the data from this preliminary study.