Process Integration: Continuous Anaerobic Digestion−Ozonation Treatment of Olive Mill Wastewater

The purification of the olive mill wastewaters (OMW) is investigated by the combination of an anaerobic digestion, followed by an ozonation treatment. Continuous anaerobic digestion (CAD) was performed in a laboratory-scale bioreactor at constant hydraulic retention time and influent organic substrate concentration. Chemical oxygen demand (COD), total polyphenolic compounds (TP), methane production, pH, total volatile fatty acids (VFA), and alkalinity were analyzed daily. The COD removal and methane yield coefficient were 81% and 295 L CH 4 /kg COD, respectively. A kinetic study is performed using the Monod model, which, when applied to the experimental data, provides the specific kinetic constant of this model. Effluent from CAD was submitted in an ozonation stage, where the temperature and inlet ozone partial pressure were varied. COD, total aromatic compounds (A), and TP removals were established. An approximate kinetic study for design purpose was developed, which leads to evaluation of the apparent kinetic constants for COD and total aromatic compounds.