The Effect of Different Concentrations of Phenol on Anaerobic Stabilization Pond Performance in Treating Petroleum Refinery Wastewater

In this study the efficiency of anaerobic stabilization pond for treating oil refinery wastewater at different concentrations of phenol is investigated. The anaerobic stabilization pond (ASP) was built from fiberglass plats (0.2m×1m×1m and 6mm thickness). The experimental apparatus was performed at HRT (2d) with hydraulic loading rate 95L/day. After inoculation of the biomass, reactor was run at different concentrations of phenol (100, 200, 300, and 400 mg/L). Sampling is carried out from effluent after achievement of steady state condition at all experimental tests. The samples for the determination of NH3, PO4 and Phenol, were analyzed using a spectrophotometer (Varian, UV-120-02). In addition, other parameters such as TCOD, SCOD, TBOD, SBOD, and pH were determined using standard methods. The results showed that the efficiency of system reduced at phenol concentrations of 100, 200, 300, 400 mg/L. The maximum and minimum removal rates of BOD and COD were 71.75±8.14; 76.07± 10.94 and 53.5±6.03, 55.63±3.47 by the system respectively at phenol concentrations of 100 and 400 mg/l. The optimum condition for phenol removal (89.82% and 55.86%) was determined with phenol concentrations of 100 mg/L and 400 mg/L, respectively. This study showed a comprehensive efficiency of anaerobic stabilization pond as a promising system to eliminate different concentrations of Phenol, COD and BOD, however increase of Phenol concentration to 400 mg/L was decreasing of system efficiency due to phenol toxicity for biomass.