A simple, fast and low-cost method for the efficient separation of hydrocarbons from oily sludge

Since a large amount of sediment organic matter and hydrophobic organic compounds presented in oily sludge sediments in petroleum storage tanks, separation or degradation of these compounds are environmentally important. Therefore, the effect of four solvents and their combinations on the extraction of hydrocarbons in oily sludge from the dredging of petroleum storage tanks in Iran was investigated in this study. Besides, the number of extraction steps and the temperature were also investigated, and the mechanical shaking method was introduced and compared with that of mixing and Soxhlet. The results showed that chloroform held the best solvent, and the combination of solvents showed better extraction than the pure solvents individually. Furthermore, hydrocarbon extraction increased as temperature and extraction steps raised. According to gas chromatography tests, all the solvents revealed acceptable extraction scales. Moreover, the amounts of extracted hydrocarbons by the mechanical shaking method had better results than that of mixer and Soxhlet. The highest percentage of that belonged to mechanical shaking method by 82.8%. It seems that the mechanical shaking method is a simple, fast, low-cost, and suitable alternative to the Soxhlet method for hydrocarbon extraction in oily sludge and petroleum sludge-contaminated soil.