The valorization of food wastes is a challenging opportunity for a green, sustainable, and competitive development of industry. Approximately 30 million m3 of olive mill wastewater (OMWW) are produced annually in the world as a by-product of the olive oil extraction process. In addition to being a serious environmental and economic issue because of their polluting load, OMWW can also represent a precious resource of high-added-value molecules such as polyphenols that show acclaimed antioxidant and anti-inflammatory activities and can find useful applications in the pharmaceutical industry. In particular, the possibility to develop novel nutraceutical ophthalmic formulations containing free radical scavengers would represent an important therapeutic opportunity for all inflammatory diseases of the ocular surface. In this work, different adsorbents were tested to selectively recover a fraction that is rich in polyphenols from OMWW. Afterward, cytotoxicity and antioxidant/anti-inflammatory activities of polyphenolic fraction were evaluated through in vitro tests. Our results showed that the fraction (0.01%) had no toxic effects and was able to protect cells against oxidant and inflammatory stimulus, reducing reactive oxygen species and TNF-α levels. Finally, a novel stable ophthalmic hydrogel containing a polyphenolic fraction (0.01%) was formulated and the technical and economic feasibility of the process at a pre-industrial level was investigated.

The olive oil industry is a sector of high relevance in the economy of the European Union; indeed, three quarters of the world production is concentrated in the South Europe. Unfortunately, the commonly used milling techniques generate huge amounts of highly polluting olive mill wastewater (OMWW) as a side‐product. If released in the environment, untreated OMWW have a detrimental impact on land and water because of the large amount of phytotoxic phenolic compounds contained. At the same time, due to their powerful antiradical properties, polyphenols represent the center of a very valuable market niche, where they find application in cosmetic and nutraceutic fields. Consequently, the mandatory (for evident environmental reasons) depollution of OMWW associated with an efficient and selective recovery of the phenolic fraction could be economically very advantageous. In the present study, a new methodology employing activated charcoal as the adsorbent phase was developed in order to depollute OMWW and simultaneously recover a fraction enriched in hydroxytyrosol, the most abundant and valuable phenolic compound present in this matrix. Moreover, to evaluate the technical and economic feasibility of the process at a pre‐industrial level, this strategy was submitted to a scale‐up process and a pilot plant prototype was developed.