A new screening model for leachate production assessment at landfill sites

This paper presents an alternative water balance model for predicting leachate production in landfills, from the operative to the post-closure management. The developed model, based on analytical and empirical equations, provides a quantitative estimation of leachate volumes, using a water balance approach which accounts for the different rates of the incoming water, water losses and water consumption. Aging and compression are also included, allowing to assess the progressive variation of hydraulic and physical properties of deposited wastes. In this work, after a brief description of the model architecture, different applications to hypothetical scenarios and to a real landfill are presented. Namely, in order to highlight how aging and biodegradation can influence the expected leachate production, the results of the developed model are also compared with those provided by the Hydrologic Evaluation of Landfill Performance model which neglects both these processes. The obtained results showed that wastes compression may affect leachate prediction in a large extent during operative stage of a landfill, and neglecting these processes could lead to underestimation up to one order of magnitude. Also biodegradation of waste organic matter may result relevant for leachate volumes assessment, influencing water storage capacity of wastes and leading to a leachate production 2–3 times greater than those obtained neglecting these phenomena. Finally, the application of the developed model to the real landfill shows a quite good agreement with the field data, whereas the Hydrologic Evaluation of Landfill Performance model tends to underestimate the leachate volumes with errors up to 80 %.

Keywords
Biological-hydrological processes; Compression; Percolate; Water balance model; Wastes