Abstract
This investigation compared the performance of Fenton and photo-Fenton oxidation processes in the treatment of sulfidic spent
caustic wastewater. Response surface methodology, particularly central composite design was used to investigate the effect of
Fe/H2O2 and H2O2/COD in assessing treatment process efficiency. Empirical models were developed to describe the relationship
between the factors and responses. The models were validated through analysis of variance and were further used in process
optimization. The best solution for Fenton process was found to be at Fe/H2O2 and H2O2/COD ratio of 0.07 and 2.52
correspondingly. On the other hand, lower H2O2/COD ratio of 1.84 was achieved in photo-Fenton process. Removal of COD and
sulfide up to 97% and 100% was observed with photo-Fenton process.