Study on production and transfer of leachate in a waste landfill

During the study of different landfill barrier systems conducted on a real site, operated by CGEA-ONYX, with financial help from the French Ministry of the Environment and the Agency for the Environment and Energy Control, the quantity of drained leachate and rainfall on site were measured. For the past three years, the IRIGM-LGM has been working simultaneously on two complementary studies: characterisation of the waste in laboratory and numerical modelling of the hydraulic behaviour of waste. The experimental installation is used to define the hydraulic characteristics of the waste: permeability and water content, which depend on capillary pressure. Data obtained on site were also used to adjust the numerical computer model. The simulation is based on a model of hydraulic transfer in a porous medium. This is a finite-element, two-dimensional transient model. This work is important for two reasons: before construction of the landfill site, it can help to evaluate the drainage system and leachate treatment installation; during operation, it may be possible to detect a harrier watertightness problem.