The paper introduced scum sludge to biodiesel production and
compared the biodiesel yield of scum sludge with that of primary
and secondary sludge through ex-situ and in-situ production systematically.
The results had shown that scum sludge had almost
twice calorific value of primary and secondary sludge under
freeze-drying. However, all sludge types contained a significant amount of palmitic acid (C16:0) and oleic acid (C18:1) regardless of
the co-solvent used in extraction. Palmitic acid methyl ester was
the dominant component in the FAMEs and accounted for approximately
45% and 37% of total biodiesel produced from primary and
secondary sludge respectively. However oleic acid methyl ester
was the dominant component in the FAMEs produced of scum
sludge and constituted more than 35% of total biodiesel