composting procedures to obtain valuable organic fertilizers (Altieri and Esposito, 2010; Arvanitoyannis and Kassaveti, 2007; Tortosa et al., 2012).
Although the effect of OMW application on soil properties has been extensively studied, only a few studies have so far addressed the potential contamination of groundwater due to leaching of nutrients and polyphenolic compounds (Chartzoulakis et al., 2010; Mekki et al., 2007; Moraetis et al., 2011; Spandre and Dellomonaco, 1996). Available data on the subject are often contradictory and safety of OMW application has not been fully assessed yet. More- over, no studies are available so far about potential contamination of groundwater due to land application of olive waste compost.
The purpose of this study was to evaluate how the leaching of potential pollution from OMW and olive waste compost may reach groundwater. Two sets of lysimeters were assembled using two different soils sampled in Southern Italy. Five treatments, based on the application of either OMW or composted pomace, were compared by analysing selected chemical and physical parameters of water leached through soil columns.