Characteristics of solid residues from olive oil processing as bulking material for co-composting with industrial wastewaters

The present work concentrates on the study of the chemical and physical characteristics of the olive oil processing solid residues. The investigation aims to use the resulting material as an organic substrate for the production of organohumic compounds either by composting it or by co-composting it, using effluents containing high organics. The chemical characteristics, that were studied with respect to particle size, include moisture content, fats and oils, lignin, wood, total carbon total nitrogen, total phosphorous, total sugars, hemicellulose, cellulose, and ash. The physical characteristics that were studied according to particle size were water holding capacity, porosity, density, apparent density. The experimental results indicate that the olive oil processing solid residues constitute a suitable solid organic substrate for the development of the composting process by providing that adjustments of the moisture content, phosphorous and nitrogen are made, or for co-composting with industrial effluents that would supplement the rest of the required moisture, nitrogen, phosphorous and easy degradable carbon compounds.