Oil extraction from scum and ex situ transesterification to biodiesel

Abstract

The aim of this study is to investigate the extraction of oil from scum obtained from a municipal wastewater treatment plant. Various parameters such as solvent volume, temperature, agitation and moisture content were optimized to maximize the oil extraction efficiency using freeze-dried scum. The oil extraction efficiency was compared for each parameter using hexane and petroleum diesel as a solvent. The optimum physical parameters for oil extraction using freeze-dried scum were 75 g solids/L solvent, temperature 60 °C, agitation 300 rpm for 60 min, and maximum oil extraction efficiency of 100 and 94.3% w/w was obtained using hexane and petroleum diesel, respectively. The obtained results using 1 g of scum were further validated using 1 kg of wet scum under optimized conditions, and oil extraction efficiency of 94.1 ± 1.3 and 91.3 ± 4.2% w/w was obtained using hexane and petroleum diesel, respectively. Furthermore, ex situ transesterification was performed, and results showed that scum had a higher neutral lipid. In brief, scum is a potential feedstock for the production of biodiesel, and more work on this must be done in future.

Keywords:

• Wastewater sludge
• scum
• oil extraction
• petroleum diesel
• ex situ transesterification
• biodiesel

Acknowledgements

Sincere thanks are given to the Natural Sciences and Engineering Research Council of Canada (Grant A 4984 and Canada Research Chair) for their financial support. The views and opinions expressed in this paper are those of the authors. We are grateful to technical staffs of INRS-ETE, for their timely help to analyze the sample on FT-IR and GC-FID.

Additional information

Funding

This work was supported by ‘Natural Sciences and Engineering Research Council - NSERC, Canada’, [grant number A 4984 and Canada Research Chair].