Development of novel oil recovery methods for petroleum refinery oily sludge treatment

Oily sludge is one of the most significant wastes generated in the petroleum industry. It is a complex emulsion of various petroleum hydrocarbons (PHCs), water, metals, and fine solids. Due to its hazardous nature and increased generation quantities around the world, the effective treatment of oily sludge has attracted widespread attention. The complexity of its composition and diversity of its origin sources make oily sludge management a difficult and costly undertaking. Many methods have been developed for the treatment of oily sludge through oil recovery or sludge disposal approaches, but no single specific process can be considered as a panacea since each method is associated with different advantages and limitations. Efforts should focus on the improvement of current technologies and the combination of oil recovery with sludge disposal in order to comply with both resource reuse recommendations and environmental regulations. The object of this study was to develop novel combined methods for oil recovery treatment on different refinery oily sludges. The investigation focused on the oil recovery performance of combined methods based on four individual treatment processes including ultrasonic irradiation, solvent extraction, freeze/thaw, and pyrolysis in oily sludge treatment. "~The results of this research indicate that the combined oil recovery methods have the potential to be applied for the treatment of different complex oily wastes in petroleum refining industries to meet sustainable development principles. --Leaves 2-5.