Treatment of Refinery Wastewater by Chemical Advanced Oxidation Processes (UV-Photolysis, Fenton, and Photo-Fenton): A Comparative Study

A huge amount of oily wastewater is discharged from industrial activities, especially the refinery plants. Therefore, scientists focus their research on the investigation of effective methods to treat this kind of wastewater. This work investigates and compares the effectiveness of chemical advanced oxidation techniques to remediate real refinery wastewater generated from the Al-Samawa refinery plant which has not been treated before by using the present technologies. Real refinery wastewater underwent a batch photo-Fenton oxidation treatment (UV/H2O2/Fe2+) to reduce the oil content. The experiments were designed using a factorial experimental design containing the effects of 30-90 min irradiation time, 25-250 ppm hydrogen peroxide, and 2-8.5 pH. A statistical program was used to analyze the results. The optimum values of these variables were 90 min, 100 ppm H2O2, and pH 3. The effect of solution temperature on the removal efficiency was studied in the range of 20-400 degree celsius. It was found that the temperature notably influences the treatment process, where the highest removal of the organic content of 95.15% was achieved at 30degree celsius. Adsorption equilibrium investigation revealed that the Langmuir model was a more fitted model (R-2 = 0.9999) for photoFenton elimination of oil content than other isotherm models. Consequently, a comparative study of the treatability of UV-photolysis, Fenton, and photo-Fenton processes has been conducted. The core findings of this comparison showed that the oil content removal by using the UV-photolysis process is (49.2%), the Fenton process (69.6%, while it shows that the photo-Fenton process is the most effective at getting rid of pollutants (92.75%). As observed the photo-Fenton methods are more effective than other studied methods to treat refinery wastewater.