Background The fact that fresh olive pomace, the by-products of new continuous two-phase extraction processes, is not liked by oil extractors because of its high liquid content has made its disposal a pressing matter. This problem does not actually exist, however, in view of the potential for pomace spreading, as foreseen by recent national legislation (law 574/96). Agronomic applications, however, have highlighted two handling problems: dripping of pomace during transport, and the highly disagreeable odour it gives off during spreading, especially after long storage periods. In the framework of Community policies, measures to reduce environmental impacts or to maintain environmental values in this field have been carried out on an extremely small scale, compared with the resources devoted to production support and production-oriented structural objectives. Objectives The aim of the project is to significantly reduce the environmental impact of the disposal of olive mill industry by-products. The project focuses on developing a co-blending strategy to combine, in a recycling plant, olive oil waste waters, fresh olive pomace and other natural organic by-products, into an 'improved' waste mixture for agricultural land application. The project aims at: 1. maximising the recovery of biomass coming from the processing of olives (85% of by-products in the EU) as a soil amendment, in compliance with EU laws; 2. placing on the market a sufficient amount (12000000 t per year in the EU) of organically rich materials, in order to reduce mineral fertilising costs (100,000,000 € per year in EU), with beneficial effects on chemical and physical soil properties. 3. The recovery of ground stones (1500000 t per year in EU), equivalent to 110,000,000 € per year in the EU; 4. providing alternative destinations to fresh olive pomace; 5. creating a new and versatile plant, to be integrated with the oil production process, thus complementing it. Results The project has been concluded successfully: it satisfies all the criteria from an environmental and socio-economic point of view, in fact: 1. the final products of the process allows integrated use of different bio-wastes from the agro-food industry and agricultural production, as the experimental mixes produced, present values compliant with the reference limits set by Italian regulations for simple vegetal non-composted amendments or for mixed composted amendments (Law 748/84), with characteristics that also make them suitable for Organic Agriculture (Reg 2092/91 and MiPAF Circular n. 8 of 13 September 1999); 2. The mixes contributed to a significant increase of the content of organic substance in the treated soil; 3. The amending properties of the mixes are well proved: a comparison among the three tested mixes and trees fertilised with urea indicates that the nutritional input provided by the experimental mixes is equivalent to nitrogen-enriched fertiliser; 4. The experimental fertilising treatment does not affect the quality of the oil; 5. It is possible to wash the stones at a sustainable cost. Moreover, preliminary test results confirm that the stone represents a good quality fuel in consideration of its low pollutant emissions and high thermal value. More research into fine tuning the combustion plants is however required; 6. The spreading of organic substrate produced from oily effluent can have a suppressant effect on populations of gall-forming nematodes, in addition to the numerous other agronomic benefits that derive from the input of organic substance into the soil. Spreading of organic substrate could therefore be considered an option in nematode-suppressant strategies having low environmental impact. 7. A great aspect of the project consists of addressing a variety of National and European legislation on the matter: at the end of the project, the International Oleic Council is interested in studying a sole international proposal of a law regarding the oil waste treatment and recycling and an Italian MEP (Alfonso Adria) supported the TIRSAV dissemination activity and is available to support also for a discussion on the oil waste treatment and recycling problem in the DG Environment; 8. The beneficiary produced a costs/benefit analysis regarding the plant, which is a part of final publication: it is very detailed and clear (12 scenarios taken into account; the scenarios 10, 11, 12 show that considerable increases in profits can be obtained through only slight variations in the price of the compost); 9. An association of Italian Olive Producers (APROL) requested the assistance of ISAFOM CNR and VMA to project a similar plant in Puglia, of greater size, in order to cover the needs of a consortium; 10. The International Oleic Council is interested in implementing similar projects in Morocco, Tunisia, Syria; 11. The Olive Oil Producers Association of Messina, interested in the project, organised a dissemination meeting and implemented a plant based on the TIRSAV technology; 12. The TIRSAV technology has been patented; 13. The Pieralisi S.p.A., one of the most important firms in olive oil production plant is interested in buying the licence of use of the patent.