Oil recovery from lime-treated wastewater of olive mills

Abstract

Olive mill wastewater is a by-product of olive oil production and generates a major environmental problem in the Mediterranean area. The amount of oil and grease, which is one of the parameters used for the characterization of this wastewater, cannot be determined easily using a standard method. Therefore some modifications of the standard method were investigated in this study. To this end wastewater was first treated with lime, without using diatomaceous-silica, then acidified, filtered through muslin cloth only, and finally extracted with an organic solvent. However, the results obtained by the modified method didn't differ significantly from those obtained by the standard method. Furthermore some tests were conducted to recover the remaining oil, which may be economically important, in these waste products. The oil could be recovered in the range of 70.6 to 96.4% if the wastewater was treated with lime while air was passed through the mixture, filtered using a muslin cloth disk, dried, and extracted with an organic solvent.