Prediction of Long-term Leachate Generation in a Municipal Solid Waste Landfill in an Arid Climate

摘要

In wet climates, leachate formation is inevitable and continues over a long period. However, in arid climates, evaporation considerably exceeds precipitation so that the source of leachate is mainly limited to the water derived from the waste in the landfill. This also implies that leachate generation will eventually cease, and that the waste inside the landfill will gradually dry out. However, to date, this has not been shown quantitatively. In this study, a simple water balance model was created and applied to estimate the time period for which leachate was generated using meteorological data obtained in an arid climate. Several meteorological stations located in arid climates were selected according to the Köppen-Geiger climate classification (in Iran, USA, and Australia), and their climate data from 2000-2013 were used in the model. The configuration of a small trench that exists in landfills in Iran was taken as the landfill form in each location. The results showed that leachate was generated only for the period in which municipal solid waste (MSW) was disposed of because most of the source of leachate was formed by the moisture derived from the waste, and the greater part of the precipitation was consumed by evaporation. Almost no leachate was generated after the end of the disposal operation. This scenario applied for all of the modeled regions. The quantity of water inside the landfill was also calculated. The results from all locations indicated that the quantity of water in the landfill started to decrease after the completion of the waste disposal operation, which implies that the waste inside the landfill will subsequently dry out.