Degradation of phenolic wastewater by ozonation and Fe-based catalytic ozonation in multi injection bubble column reactor

The concept of liquid waste describes phenol compounds as dangerous pollutants because of the toxicity they confer, corrosion and carcinogenicity. They are actually found in many industrial wastewaters and widely studied because of its adverse effects on the environment. The idea behind this study was due to the existence of significant weaknesses in conventional processing to degrade or remove phenol compounds in industrial wastewater hence necessitating the use of the ozonation technology. This research further aims to evaluate the performance of this technique in multiple injection columns, with or without the use of catalysts (e.g. Fe), in the degradation of phenolic wastewater. The process involved the variation of wastewater discharged (255, 405, 495) mL/min, air flow rate (8, 10, 12) L/min and the amount of the catalyst in weight (50, 100, 200) g to be investigated. Furthermore, the trend of decreasing phenol and COD levels was observed, using a UV-vis spectrophotometer. The results of this study indicate the degradation process with and without catalytic ozonation, extracted phenol up to 99.12% and 99.48% respectively, while the amount of COD reduced were 50.72% and 77.69%. The optimum condition for the treatment process was obtained at pH 12 with an air and wastewater flow rate of 10 L/min and 0.495 L/min respectively in non-catalyzed ozonation method. Furthermore, the use of Fe-based catalysts negatively affected the performance of the process as their presence seems to overload the performance of the ozonation, thereby serving as an inhibitor of phenol oxidation.