A chemical-biological integrated approach for the valorization of olive mill wastewaters

An integrated chemical-biological process for the recovery of natural phenolic compounds from an olive mill wastewater (OMW) and for the anaerobic production of volatile fatty acids (VFAs) from the pre-treated OMW was developed in this work. The recovery of OMW polyphenols was carried out through solid phase extraction (SPE) by using Amberlite XAD16 resin as the adsorbent and ethanol as the biocompatible desorbing phase. Thereafter, the acidogenic digestion of the dephenolized OMW was performed in a mesophilic packed-bed biofilm reactor filled with ceramic cubes, who was operated at an OLR of about 5.9 g L-1 day-1. As a result of the integrated process, more than 60% of polyphenols were recovered and 19 gCOD L-1 of VFAs were obtained, representing more than 70% of the anaerobic effluent COD.