Glycerin esterification of scum derived free fatty acids for biodiesel production.

•Oil extraction from waste water scum via acid hydrolysis and solvent extraction.•Acyl-glycerol formation reactions and trends during catalyzed glycerolysis.•Free fatty acid reduction kinetics of scum derived oil for biodiesel production.•Inorganic catalyst comparison versus uncatalyzed reaction kinetics.•Sulfur reduction potential of catalysts during filtration of glycerized oil.