Test investigation of percolation through municipal solid waste (MSW) with a triple function physical model

Abstract

In this study, municipal solid waste (MSW) was considered as a three-phase structure including a waste body with a given field capacity and permeability, preferential channels with high permeability and impermeable sections. Hence, a landfill simulation reactor (LSR) consisting of rockwool and Sand (as the waste body), copper pipes (as preferential channels) and plastic pieces (as impermeable sections) was operated to analyze the leachate percolation from a landfill site. Waste permeability and field capacity were formulated as a function of two operating variables (impermeable sections and preferential channels) using response surface methodology (RSM). The results indicated that the preferential channels increased the MSW permeability; however, they did not affect the field capacity significantly. It was also found that even small changes in the impermeable sections severely affected both the permeability and the field capacity of MSW. The obtained experimental data and the actual leachate data of full-scale cells in Tehran Landfill were used to calibrate the landfill parameters. According to the calibration results, the estimated volume of impermeable sections in the landfill was 15.05% per cubic meter MSW, of which, 10% is activated in recirculation and intense precipitations (as secondary field capacity). Besides, the ratio of leachate discharge through preferential channels (instantly) to the total discharge was estimated at 0.26 and the travel time of leachate through the waste body was approximately 46 days.