Environmental problem targeted

In terms of area occupied, the olive trees are among the most cultivated crops in the Mediterranean basin. There are approximately 750 milion productive olive trees worldwide, occupying an area of 7 million ha. The Mediterranean region alone provides 98% of the total surface area dedicated to olive orcharding and 97% of the olive world production, which is, on average, 17,000x10³tons per year (Faostat 2007). The main olive oil producers are Spain (27%), Italy (26%), Greece (18%), Turkey (6%) and, to a lesser extent, Tunisia, Morocco and Syria (4% each) and Portugal, Egypt and Algeria (2% each).

The amount of olive waste generated, about 13,500x10³tons per year, represents a key environmental problem in Mediterranean areas, especially because the olive oil production is concentrated between November and March. The olive waste is thus generated in huge quantities in a short period of time and, due to considerable concentrations of phenols, lipids and organic acids, it is also highly phytotoxic. On the other hand, these residues contain valuable resources like large quantities of organic matter and a wide range of recyclable nutrients.

For many years, the olive mill waste water (OMWW), produced by the three-phases system, has been the most pollutant waste produced by the Mediterranean olive mills. For this reason the management of this liquid residue was extensively investigated. However, from the early 1990s, the implementation of a new extraction two-phase system, mainly in Spain, originated a new solid waste (TPOMW or alperujo) which requires specific management since it causes a different environmental impact.

By now, the careless management of these hazardous residues has been representing an environmental concern for water, soil and atmosphere. In contrast, numerous environmental and social benefits could be obtained by producing either biogas via anaerobic fermentation, or biomass through phytoremediation. The energy obtained by the valorization of the olive waste meets the requirements of the EU White Paper on Renewable Energy encouraging the development of alternative ways of renewable energy production in order to reduce CO₂ emissions.

The problem of the disposal/reutilization of the olive wastes is strictly related to EU environmental policies according the following legislations:

6^th EAP, EU Directive: (I) 2000/60/EC in matter of water policy;
2006/12/EC in matter of waste policy;
COM (2006) 231, COM (2006) 232, SEC (2006) 1165 and SEC (2006) 620 in matter of soil protection;
The European Strategic Energy Technology Plan (Set-Plan IP/07/1750) in matter of energy policy.