RECOVERY OF POLYPHENOLS FROM OLIVE MILL WASTEWATER BY NANOFILTRATION

In this research, the efficiency of an integrated acid cracking membrane filtration system in the treatment of olive mill wastewater (OMW) was investigated. OMW was pretreated by acid cracking and subjected to three stages of microfiltration (MF) through membranes with nominal pore sizes of 50, 5 and 0.2 mu m. These stages led to reductions of 99%, 23% and 52% in the content of suspended solids, total phenols and chemical oxygen demand (COD), respectively. Then, MF permeates were subjected to ultrafiltration (UF), followed by nanofiltration (NF). The COD and the amount of phenolic compounds obtained as a result of OF were of 50.2% and 60.8%, respectively. NF showed high efficiency in decreasing COD (more than 90%) and in the removal of phenolic compounds (78.3%), as well as moderate desorption of mineral salts (41%). Also, the effect of operating parameters, such as pressure and volume reduction factor (VRF), on the membrane flux was investigated. The results achieved are in good agreement with those reported in the literature.