title: Scum sludge as a potential feedstock for biodiesel production from wastewater treatment plants.
abstract: The main goal of this study was to compare the component and yield of biodiesel obtained by different methods from different sludge in a wastewater treatment plant. Biodiesel was produced by ex-situ and in-situ transesterification of scum, primary and secondary sludge respectively. Results showed that scum sludge had a higher calorific value and neutral lipid than that of primary and secondary sludge. The lipid yield accounted for one-third of the dried scum sludge and the maximum yield attained 22.7% under in-situ transesterification. Furthermore the gas chromatography analysis of fatty acid methyl esters (FAMEs) revealed that all sludge contained a significant amount of palmitic acid (C16:0) and oleic acid (C18:1) regardless of extraction solvents and sludge types used. However, the difference lay in that oleic acid methyl ester was the dominant component in FAMEs produced from scum sludge while palmitic acid methyl ester was the dominant component in FAMEs from primary and secondary sludge. In addition, the percentage of unsaturated fatty acid ester in FAMEs from scum sludge accounted for 57.5-64.1% of the total esters, which was higher than the equivalent derived from primary and secondary sludge. In brief, scum sludge is a potential feedstock for the production of biodiesel and more work is needed in the future.
authors.affiliation: School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China. Electronic address: wangyi1003@sina.com.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
authors.forename: Sha
authors.initials: S
authors.lastname: Feng
authors.affiliation: School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Bai
authors.affiliation: College of Chemistry & Materials Science, Northwest University, Xi'an 710069, China.
authors.forename: Jingchan
authors.initials: J
authors.lastname: Zhao
authors.affiliation: School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; School of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Siqing
authors.initials: S
authors.lastname: Xia
mesh_terms: D056804:Biofuels / Q000032:analysis*; D002681:China; D005227:Fatty Acids / Q000032:analysis; D012722:Sewage / Q000032:analysis*; D018505:Waste Management / Q000379:methods*; D062065:Wastewater / Q000032:analysis*
chemical_list: D056804:Biofuels; D005227:Fatty Acids; D012722:Sewage; D062065:Wastewater
keywords: Biodiesel production; Scum sludge; Wastewater treatment plant