In- situ transformation of municipal sewage sludge into biodiesel | 52452
Journal of Fundamentals of Renewable Energy and Applications

Journal of Fundamentals of Renewable Energy and Applications
Open Access

ISSN: 2090-4541

In- situ transformation of municipal sewage sludge into biodiesel

International Congress and Expo on Biofuels & Bioenergy

August 25- 27, 2015 Valencia, Spain

R S�?¡nchez-V�?¡zquez, I A Vasiliadou, Juan A Melero, F Mart�?­nez, L Fernando Bautista, J Iglesias, G Morales and R Molina

Scientific Tracks Abstracts: J Fundam Renewable Energy Appl

Abstract :

Biodiesel production is gaining attraction as an efficient alternative for the valorization of sewage sludge. This waste, which
can be considered as a raw material, contains significant quantities of free lipids (10-30 wt%) liable to be transformed into
biodiesel. Nevertheless, the low-quality of this feedstock makes necessary the use of novel conversion technologies, such as
heterogeneous acid catalysis. This contribution deals with the extraction of lipids from primary and secondary sewage sludge
collected from a wastewater treatment plant and their use in the synthesis of biodiesel over highly poison-resistant heterogeneous
acid catalyst based on SBA-15-supported zirconium. Catalytic tests were performed in a 25 mL stainless-steel autoclave. The
sludge was treated with different organic solvents to extract the lipids which were subsequently transformed into biodiesel over
Zr-SBA-15 (two-step process). Alternatively and advantageously, similar experiments were carried out using directly the dried
and wet sludge, without previous extraction (in-situ process). Zr-SBA-15 catalyst provided high biodiesel yields when processing
primary and secondary sewage sludge in both the ‘two-steps’ and the ‘in-situ’ processes, converting almost 95% of the saponifiable
fraction (free fatty acids and triglycerides) into fatty acid methyl esters (FAME). It must be noted that such good catalytic results
are obtained even in the presence of high amounts of unsaponifiable matter and other impurities, typically accompanying such
wastes. Besides, the excellent results (92%) obtained with wet (non-previously dried) sludge in the in-situ process demonstrate the
high water tolerance of the Zr-SBA-15 catalyst, allowing to avoid the necessity of a sludge drying pretreatment.

Biography :

R Sánchez-Vázquez received her PhD in 2013 from Universidad Rey Juan Carlos of Madrid working on biodiesel production by heterogeneous acid catalysts.
She undertook a Pre-doctoral research in the group of Prof. Adam Lee and Karen Wilson at Cardiff Catalysis Institute working on the synthesis of mesoporous
Zr-SBA-15 hybrid materials for biodiesel production. She carried out a Postdoctoral research in European Bioenergy Research Institute working on isosorbide
production. She has published 10 papers in reputed journals and her teaching experience has been developed entirely at Universidad Rey Juan Carlos with
different graduate and Postgraduate teaching responsibilities.