An Investigation into the Role of Secondary Leachate Collection System in Landfills by Laboratory Modeling

The role of secondary leachate collection system in solid waste landfills was investigated in a laboratory model. The model was designed to incorporate three-layer soil system, a top source reservoir, and a bottom receptor reservoir. From top to bottom, the source reservoir simulated the primary leachate collection system (PLCS), the first clayey silt layer simulated the primary compacted liner, the fine gravel layer simulated the secondary leachate collection system (SLCS), the second clayey silt layer simulated the secondary liner, and the bottom receptor reservoir simulated the underlying aquifer. During the test source and receptor solutions were taken and analyzed for chloride concentrations. Also samples were taken from the fine gravel layer to observe the chloride concentration change in the SLCS with time. At test termination, the soil samples were extruded from the model, sliced, and chloride concentration was measured in soils depth. The computer code POLLUTE was used to predict the observations. The results showed that the unsaturated SLCS could play a role in concentration decrease in the underlying soils. The model is shown to perform well and provide a useful laboratory methodology for small scale experimental modeling of engineered landfills. The observations were in good agreement with the theoretical predictions made by POLLUTE.

• ABSTRACT

• INTRODUCTION

• THE LABORATORY MODEL

• MATERIALS

• TEST METHOD

• THEORETICAL MODELING

• SUMMARY AND CONCLUSIONS

• REFERENCES