Survey on Treatment Ability of Stabilization Pond as a Natural Treatment System in Oil Refinery Wastewaters

An oil refinery is one industry that introduces large amounts of toxic phenol in receiving waters annually. Hence, the aim of this study was phenol removal from oil refinery wastewater by a natural treatment system of a stabilization pond. In this study, a pilot-scale pond volume, hydraulic load, and hydraulic retention time were 200 L, 40 L/day and five days, respectively. Influent concentration of phenol was 100-400 mg/L. Responses of the process were NH3, PO4, phenol, TCOD, SCOD, TBOD, SBOD, and pH. The results showed that increasing phenol concentration and decreasing temperature have negative effects on system efficiency. Maximum removal of NH3, PO4, phenol, TCOD, SCOD, TBOD, and SBOD were 61.08, 70.09, 93.58, 80.18, 78.89, 78.7, and 76.84% in high temperature, respectively. Maximum efficiency of wastewater treatment system was obtained in phenol concentration at 100 mg/L. Also, anaerobic stabilization ponds are cost-effective options with simple operation that can be employed for the treatment of phenol content of oil refinery wastewaters.