DESCRIPTION OF A PILOT PLANT FOR THE CO-COMPOSTING OF THE SOLID RESIDUE AND WASTEWATERS FROM THE OLIVE OIL INDUSTRY

Abstract

The co-composting of the solid residue and wastewater from the olive oil production process have been studied as a new method for the treatment of wastewater containing high organic and toxic pollutants. The experimental results for a demonstration plant using solid residue from olive extraction as bulking material and olive oil processing effluents as continuously fed wastewater are reported. Composting temperature was controlled between 45 and 65 °C by air supply and the wastewater addition was fed mainly in order to keep the moisture in the range of 45 to 60% and secondary to replace the carbon substrate. During twenty three days of operation in the thermophilic region, the system was fed with 263 m3 wastewater in total, which means an average rate of 11.4 m3 day-1 wastewater or 2.9 kg wastewater per kg solid residue. Then followed a three months stabilisation period in the mesophilic region until the final product reached ambient temperature.