During the last few decades, olive oil industrial sector has grown as a result of the modernization of olive oil mills, in response to the increasing demand of olive oil worldwide. As an undesired side effect, the amount of olive mill effluents (OME) increased, especially as a result of changing old batch press method for the continuous centrifugation-based olive oil production processes currently used, which ensure higher productivity. This chapter presents the state of the art of OME management, with focus on biological and advanced oxidation processes, either alone or in combination, varying in complexity, ease of operation and costs associated. Up to this moment, there isn’t a management strategy that can be adopted in a global scale, feasible in different socio-economic contexts and production scales. The most reasonable approach is to regard OME valorisation as a regional problem, defining decentralized treatment that in some cases can be implemented for a group of olive oil mills in the same geographic area. This aspect is receiving strong attention as European Commission is promoting the transition towards a circular economy, which aims at “closing the production loop” by recycling and reusing resources, bringing benefits for the environment, society and the economy.
Part of the book: Products from Olive Tree
The olive oil production is one of the main industrial activities in the Mediterranean Basin: Italy, Portugal, Greece, and Northern African countries—Syria, Algeria, Turkey, Morocco, Tunisia, Libya, Lebanon, and Egypt. Also, France, Serbia and Montenegro, Macedonia, Cyprus, Turkey, Israel, and Jordan produce a considerable annual yield. Moreover, it is an emergent agro-food industry in China, the USA, Australia, the Middle East, and China, which is expected to develop a considerable production potential. Hence, the treatment of olive mill effluents is a task of global concern. In this context, advanced separation technologies comprising membranes and adsorption resins have been a breakthrough in terms of advanced separation and purification technologies, but many aspects are still in development or under investigation. In this chapter, a focus on the use of membrane and ion adsorption technologies for the purification of these wastewaters will be given. The effect of different factors comprising the type of membrane, i.e., ultrafiltration, nanofiltration, and reverse osmosis; the type of adsorbent (waste material, resins); and the operating conditions will be addressed. Conventional treatments are not able to abate the high concentration of dissolved species present in these effluents. The use of these technologies can be a feasible solution if properly engineered.
Part of the book: Desalination
Nanofiltration (NF) technology offers several advantages over classic separation processes. NF membranes have been increasingly implemented in water treatment processes (e.g., desalination of brackish water and seawater) and for wastewater (e.g., textile, pulp and paper, pharmaceutical, and agro-industrial). The specific selectivity toward small solutes and the lower energy consumption of NF membranes have enhanced their use. However, some drawbacks need to be faced when NF is applied on an industrial scale. The main drawback is fouling that reduces the production capacity of the plant and shortens the membrane service lifetime if of irreversible nature, thus increasing the operating and capital costs. Moreover, fouling alters the selectivity of the membrane and thus the rejection efficiency. This chapter focuses the use of NF for the treatment of different agro-industrial effluents (such as dairy, tomato, and olive oil) and addresses membrane fouling as the main drawback against NF competitiveness.
Part of the book: Nanofiltration