Leachate production estimation for a landfill in south of Brazil using Hydrus-1D

Abstract

The disposal of municipal solid waste (MSW) is currently a great challenge to society mainly due to the threat posed by leachate and gases released from the decomposition sites. Landfills have been widely used for this purpose because their waterproofing, drainage and treatment systems have reduced the risks of soil, water and air contamination. Estimating the amount of leachate and gases generated is extremely important for the control and operation of these systems. In this context, this study was developed in the landfill of Timbó, State of Santa Catarina, Brazil, in order to estimate the generation of leachate and to evaluate the effect of profile composition. HYDRUS-1D was used to simulate unsaturated fluid flow through layers. Data on soil matrix such as characteristic curve and unsaturated hydraulic permeability were obtained from previous studies and pedotransfer functions and the respective curves for MSW were obtained from literature. Thirteen layers were simulated by attributing an atmospheric variably boundary condition on top cover and free drainage on the bottom of the profile for two hydrologic years (2017-2019). HYDRUS-1D overestimated the leachate volume by 33.67% when compared with field data. Layers distribution showed an attenuation effect on leachate production which is consistent with design.