Characeterization of faecal sludge and analysis of its lipid content for biodiesel production

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2014-11-13
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As urbanization continues to take place, the management of sanitation is becoming a major concern in urban areas of many African countries. For countries in Sub-Saharan Africa (SSA) to achieve the millennium development goal of halving the number of people without access to improved sanitation, a paradigm shift is needed. Aside sanitation, SSA countries lag behind the rest of the world in access to modern energy services, a situation that is militating against poverty reduction. This work looks at the characteristics that make faecal sludge (FS) from Kumasi a viable feedstock for the production of biodiesel, a renewable energy fuel. Faecal sludge from households were analysed for their lipid content, moisture content, total solids and pH. On the average, the lipid content was found to be in the range of 8.84 – 9.71% of dry FS depending on the type of faecal sludge. The moisture content varied between 82.45 – 99%, while the pH was between 6.65– 8.49. Lipids were extracted from dry faecal sludge using different methods; soxhlet extraction method (solvents: hexane, petroleum ether and methanol), ‘Bligh and Dyer’ method, Folch method and extraction with hexane-methanol-acetone combined-solvent system also known in this work as HMA extraction method. It was found that extraction with methanol yielded the highest amount of lipids, i.e., 12.67%w/w of the dry FS while petroleum ether extracted the least amount of lipids, i.e., 3.05%w/w of the dry FS. The lipids extracted with methanol contained 10.48% saponifiable matter while lipids extracted with petroleum ether contained 2.09% saponifiable matter. HPLC analyses revealed that lipids extracted with hexane and petroleum ether using soxhlet method produced the highest amount of triglycerides, i.e., 16.6% and 16.0% respectively. Soxhlet extraction with these solvents showed that they contained lower levels of free fatty acids, 2.4% and 2.2% respectively, as compared the other methods. GC analyses, indicated that all the lipids extracted from the different methods predominantly contained 16-carbon and 18-carbon fatty acids, which is a good sign since these are the kind of fatty acids in vegetable oil used as major precursors for biodiesel production.
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A thesis Submitted to the Department of Chemical Engineering, Kwame Nkrumah University of Science and Technology in partial fulfillment of the requirements for the award of the degree of Master of Science,
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