The generation of agro-industrial byproducts is increasing at a fast rate all over the world. In Mediterranean regions, the production of wine achieved a value of 2.92x10¹⁰ L in 2018 and the production of olive achieved a value of 3.2 million ton in 2015/2016. These two agro-industries generate high volumes of wastewater, with a high content alcohols, organic acids, sugars and phenolic compounds, capable of great environmental impact with notable effects such as pollution of water, degradation of soil, odors and air emissions and low biodegradability.

In this work, it was collected and reviewed recent findings aiming the feasibility of coagulation-flocculation-decantation (CFD) and advanced oxidation processes (AOPs) for the treatment of agro-industrial wastewaters. The application of plant-based coagulants and oenological coagulants revealed to be effective in the removal of turbidity and total polyphenols from the wastewater. The literature review showed that the application of AOPs was effective for the removal of organic matter from the wastewater. It was also observed by several authors that hydroxyl radical (HR)-AOPs, sulfate radical (SR)-AOPs and ozone-AOPs were more effective with the application of ultra-violet (UV) radiation, due to the increase of hydroxyl and sulfate radicals generation. Finally, based in literature review, the combination of CFD with AOPs achieved higher removal results, considering that the pre-treatment with CFD process reduces the turbidity and suspended solids from the agro-industrial wastewaters, allowing the radiation to penetrate more easily. In conclusion, the application of CFD process as a pre-treatment followed by AOPs are an efficient process for agro-industrial wastewater treatment.