“…It also represents a great environmental hazard if not properly managed. However, WW contain valuable resources, such as a high organic matter concentration and some nutrients, especially potassium, that could be usefully used to improve the physic-chemical and biological properties and then soil fertility and productivity; representing a valid option to close the residue-resource cycle (Roig et al, 2006). In Table 2 are reported the averages of main chemical WW characteristics, given by several Authors (Aktas et al, 2001;Filidei et al, 2003;Moreno et al, 1987;Paredes et al, 1999;Piperidou et al, 2000;Saviozzi et al, 1991;Vlyssides et al, 1996;Vlyssides et al, 2004-as cited in Roig et al, 2006 (Pacifico, 1989;Ramos-Cormenzana, 1986).…”