Human waste is a big problem, but might it be turned to our advantage, offering a sustainable source of biofuels to usurp oil-derived petrochemicals? An international collaboration in Africa has assessed the potential of extracting lipids (fatty molecules) from sewage sludge and converting those fatty compounds into the kind of compounds that can be blended with conventional fuels for use in vehicles of all kinds.
The team tested the process by extracting lipids from dried sewage sludge using the soxhlet extraction technique. They then carried out a conversion to biodiesel acid catalysis transesterification to make the requisite fatty acid methyl esters. They used gas chromatography-mass spectrometry (GC-MS) analysis to test the product. The materials contained a high lipid yield of almost 80 percent and the biodiesel properties considered conformed to global specifications, the team reports.
“Sewage sludge could serve as an alternative and a cheap feedstock for biodiesel development,” the team concludes.
Obisanya, J.F., Oyekunle, J.A.O., Ogunfowokan, A.O. and Fatoki, O.S. (2018) ‘Evaluation of biodiesel potential of sewage sludge’, Int. J. Environment and Waste Management, Vol. 22, Nos. 1/2/3/4, pp.61–73.