Bio-fertilization of olive oil mills liquid wastes. The pilot plant in Messinia, Greece

A method for the biological processing of olive mills liquid wastes (OMWW) for the preparation of a product suitable for agricultural use is described. This method exploits OMWW as a substrate for the cultivation of dinitrogen-fixing microorganisms (Azotobacter vinelandii) capable of transforming the material into an organic liquid of high fertilizing and soil conditioning value. The results which have been obtained from the application of this bio-fertilizer for the culture of olive trees, vines and potatoes was very promising.