Could Landfill Leachate be a Resource for a Proper Environmental Management of Closed Landfills?

Abstract

Copyright: © 2013 Del Moro G, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The disposal of urban waste into landfill has been used for long time because of its relatively low cost. One of most important drawbacks associated to such a practice is related to managing the leachate that is generated when water passes through the waste. Leachate is, in fact, the aqueous effluent generated by rainwater percolation through wastes, biochemical processes in waste cells and the inherent water content of the waste itself [1-4]. The chemical composition of landfill leachate is influenced by a number of factors including seasonal precipitation,waste composition, and, mainly, the age of the landfill [5]. Consequently, the age of the landfill site is one of the main variables that affects the leachate characteristics [4,6]. Usually, young landfill leachates contain large amounts of biodegradable organic matter (i.e., volatile fatty acids) that decrease with increasing landfill age as a result of the anaerobic decomposition that takes place in the landfill site. As the content of volatile fatty acids decreases, organic matter in the leachates becomes dominated by refractory compounds, such as humicand fulvic acid-like ones with consequent reduction of the BOD/COD ratio [7]. In addition, ammonia concentration increases at higher landfill age as a result of the fermentation of organic matter containing proteins, being concentration higher than 2 g/L typical in old landfill leachates. Therefore, stabilized landfill leachates are more difficult to treat with respect to young ones. Although leachate composition may widely vary within the successive aerobic, acetogenic, methanogenic and stabilization stages of waste evolution, three types of leachates are commonly defined according to landfill age (recent, intermediate and old).