Olive oil extraction generates a large quantity of wastewater which is a strong pollutant due to its high organic load and phytotoxic. However, its content in antibacterial phenolic substances displays to be resistant to biological degradation. The discharge of olive mill wastewater (OMWW) is not allowed through the municipal sewage system and/or in a natural effluent. Unfortunately, the current technologies for the treatment of OMWW are expensive and complicated to be operated in a mill factory where the objective of this study. We have designed and implemented a process that permitted both the treatment of agro-food processing water and the recovering of compounds of market interest. The process was applied in the effluents of olive oil mill factories to recover polyphenols with a possible significant reduction of organic waste. The nanofiltration fraction obtained from a sequential treatment involved coagulation, photocatalysis, ultrafiltration and nanofiltration was performed to separate the most valuable compounds using column adsorption runs. Competitive adsorption and the selectivity were obtained for phenol and hydroxytyrosol onto macro-reticular aromatic polymer (FPX66) and macroporous polystyrene cross-linked with divinylbenzene (MN202), respectively. The investigations were followed by a single component of phenol or tyrosol, binary phenol and tyrosol and ternary components in NF concentrate of OMWW for valuable compounds recovery conducted in a fixed-bed adsorber of resins. During the intermediate stage of the column operation, adsorbed tyrosol molecules were replaced by the incoming phenol molecules due to the lower tyrosol affinity for FPX66 resin and the tyrosol concentration was higher than its feed concentration.
Part of the book: Sorption in 2020s