Coupled photo-Fenton-biological system: effect of the Fenton parameters such as residual H2O2, Fe2+ and pH on the efficiency of biological process.

The aim of this research work is to evaluate the performance of packed-bed bioreactors under typical conditions of photo-Fenton treatment (residual iron, residual hydrogen peroxide, acidic pH). The target pollutant selected was 4-Chlorophenol which is included in the list of Priority Substances (Decision No 2455/2001/EC) in the field of water policy and amending Directive 2000/60/EC. It was found that the biological process operated correctly during eight days when the pH was in the range of 3.5-7. In the same way, the presence of hydrogen peroxide in similar concentrations to that used in the photo-Fenton process was not negative on the biological activity. On the other hand, the presence of residual iron in the biological treatment could not be observed as a consequence of the optimal dosage used for the photo-Fenton treatment. The iron dosage is still low enough to ensure non-inhibitory effects. The results obtained in this study can provide a practical knowledge for a real application.