Oil refinery wastewater treatment using physicochemical, Fenton and Photo-Fenton oxidation processes

Abstract

The objective of this study was to investigate the application of advanced oxidation processes (AOPs) to the treatment of wastewaters contaminated with hydrocarbon oil. Three different oil-contaminated wastewaters were examined and compared: (i) a ‘real’ hydrocarbon wastewater collected from an oil refinery (Conoco-Phillips Whitegate refinery, County Cork, Ireland); (ii) a ‘real’ hydrocarbon wastewater collected from a car-wash facility located at a petroleum filling station; and (iii) a ‘synthetic’ hydrocarbon wastewater generated by emulsifying diesel oil and water. The AOPs investigated were Fe²⁺/H₂O₂ (Fenton's reagent), Fe²⁺/H₂O₂/UV (Photo-Fenton's reagent) which may be used as an alternative to, or in conjunction with, conventional treatment techniques. Laboratory-scale batch and continuous-flow experiments were undertaken. The photo-Fenton parametric concentrations to maximize COD removal were optimized: pH = 3, H₂O₂ = 400 mg/L, and Fe²⁺ = 40 mg/L. In the case of the oil-refinery wastewater, photo-Fenton treatment achieved approximately 50% COD removal and, when preceded by physicochemical treatment, the percentage removal increased to approximately 75%.

Keywords:

• Oil refinery wastewater
• hydrocarbons degradation
• photocatalysis
• Fenton's reagent
• Chemical oxygen demand (COD)

Acknowledgment

The authors wish to acknowledge the co-operation of the ConocoPhillips Whitegate Refinery Ltd., Whitegate, County Cork, Ireland for providing wastewater samples.

Notes

*Chemical Oxygen Demand, **Suspended Solids.