Removal of residual oil in storage tanks by a bacterial consortium existing in wastewater of Kermanshah oil refinery

Residual oil in the storage tanks usually lead to accumulation of oily sludge which should be treated and disposed in a suitable manner. In this paper, the bacterial consortium of oil sludge in Kermanshah plant wastewater was used for treatment of oily slug in storage tanks. Broth culture was used for culturing bacteria. In this work, effect of many parameters on degradation process was investigated such as temperature, pH, oily slug content, phosphate ion, residence time and humidity. Results show that the maximum of microorganisms efficiency was in pH of 7.5 and the temperature of 30oC. Removal of hydrocarbons was decreased in both increase of phosphate ion and decrease of humidity. Also the results indicated that the use of microorganisms in the refinery wastewater treatment of oily sludge in storage tank was an efficient, inexpensive method, and also reduced hydrocarbons to acceptable levels.