An in-situ transesterification of municipal activated sludge for biodiesel production

Activated sludge is a potential feedstock for biodiesel production with co-benefit in waste remediation and sustainable energy compared to other food-based materials. In this research, the wasted activated sludge was examined with in-situ transesterification process. The optimal mass ratio of methanol to sludge, H2SO4 catalyst concentration (v/v to methanol) and temperature were investigated as 8:1, 5% and 75°C, respectively. The highest yield was observed at 8 h of retention time being 5.28%. Three most popular fatty acid methyl esters (FAMEs) were palmitic acid (C 16:0 with 27.76% mol/mol FAMEs), oleic acid (C 18:1 with 19.30% mol/mol FAMEs) and palmitoleic acid (C 16:1 with 16.93% mol/mol FAMEs). The optimal extraction conditions were in congruent with other studies with promising FAMEs yield, implying surplus fatty acid content of this local feedstock. The physio-chemical properties of FAMEs needed further improvement to please the standard and commercialization requirement.