Moreover, Michailides et al. (2011) developed a full-scale system for aerobic biological treatment of OMW. Continuous recirculation of the wastewater was used to provide oxygen concentrations from 0.7 to 1.2 mg/L. This system reduced 50% of phenolic concentrations under a HRT of 24 h, a higher aeration time does not allow to increase the reduction of polyphenols.