title: A combination of solvent extraction and freeze thaw for oil recovery from petroleum refinery wastewater treatment pond sludge.
abstract: A combination of solvent extraction and freeze thaw was examined for recovering oil from the high-moisture petroleum refinery wastewater treatment pond sludge. Five solvents including cyclohexane (CHX), dichloromethane (DCM), methyl ethyl ketone (MEK), ethyl acetate (EA), and 2-propanol (2-Pro) were examined. It was found that these solvents except 2-Pro showed a promising oil recovery rate of about 40%, but the recycling of DCM solvent after oil extraction was quite low. Three solvents (CHX, MEK and EA) were then selected for examining the effect of freeze/thaw treatment on improving the quality of recovered oil. This treatment increased the total petroleum hydrocarbon (TPH) content in recovered oil from about 40% to 60% for both MEK and EA extractions, but little effect was observed for CHX extraction. Although the solid residue after oil recovery had a significantly decreased TPH content, a high concentration of heavy metals was observed, indicating that this residue may require proper management. In general, the combination of solvent extraction with freeze/thaw is effective for high-moisture oily hazardous waste treatment.
authors.affiliation: WZU-UNBC Joint Research Institute of Ecology and Environment, Wenzhou University (WZU), Wenzhou, Zhejiang Province, PR China; Environmental Engineering Program, University of Northern British Columbia (UNBC), Prince George, British Columbia, Canada V2N 4Z9.
authors.forename: Guangji
authors.initials: G
authors.lastname: Hu
authors.affiliation: WZU-UNBC Joint Research Institute of Ecology and Environment, Wenzhou University (WZU), Wenzhou, Zhejiang Province, PR China; Environmental Engineering Program, University of Northern British Columbia (UNBC), Prince George, British Columbia, Canada V2N 4Z9. Electronic address: Jianbing.Li@unbc.ca.
authors.forename: Jianbing
authors.initials: J
authors.lastname: Li
authors.affiliation: School of Resource and Environmental Science, Wuhan University, Wuhan, Hubei Province, PR China.
authors.forename: Haobo
authors.initials: H
authors.lastname: Hou
mesh_terms: D005615:Freezing; D006256:Hazardous Waste; D007220:Industrial Waste; D000066388:Oil and Gas Industry; D010578:Petroleum; D061005:Ponds; D059027:Recycling / Q000379:methods*; D012722:Sewage; D012997:Solvents / Q000737:chemistry*; D062065:Wastewater / Q000737:chemistry*
chemical_list: D006256:Hazardous Waste; D007220:Industrial Waste; D010578:Petroleum; D012722:Sewage; D012997:Solvents; D062065:Wastewater
keywords: Freeze thaw; Oil recovery; Oily sludge; Petroleum hydrocarbons; Solvent extraction