Treatment of olive mill wastewater by combined advanced oxidation and biodegradation

In the present study, olive mill wastewater (OMW) treatment is investigated experimentally in various stage processes of advanced oxidation with ozone (O-3), photodegraclation by UV radiation, and an aerobic biodegradation. The effects of these treatment processes on the removal of chemical oxygen demand (COD) of OMW are monitored. For both single-stage treatment of O-3 and two-stage treatment of O-3/UV, the chemical oxygen demand remains quite high. In contrast, a combination of biological and UV/O-3 process for the OMW treatment seems to be a serious alternative in the reduction of the COD. In particular, biodegradation of UV/O-3 pretreated OMW found to have the highest removal levels; the percent of COD removal reaches about 91%. On the other hand, the kinetic study shows that the decay of chemical oxygen demand follows a first-order and pseudo first-order models for advanced oxidation and biodegradation processes; respectively. (C) 2009 Elsevier B.V. All rights reserved.