Determination of key operating conditions for the photocatalytic treatment of olive mill wastewaters

The TiO2-mediated photocatalytic treatment of olive mill wastewater (OMW) was investigated in a batch type, laboratory scale photoreactor. UV-A irradiation was provided by a 400 W, high pressure mercury lamp and Degussa P25 TiO2 was used as the catalyst. A factorial design approach was used to study the effect of various operating conditions such as initial organic loading, TiO2 loading, pH, contact time and the addition of hydrogen peroxide on the conversion of COD and total phenols and experimental models describing the respective removals were developed. Effluent decolorization as well as process efficiency in terms of energy consumption were also evaluated. Finally, the acute ecotoxicity of OMW samples prior to and after photocatalytic treatment was assessed.