Direct liquid - liquid extraction of lipid from municipal sewage sludge for biodiesel 1 production 2 3

16 Municipal sludge from wastewater treatment plants is a promising lipid feedstock for 17 biodiesel production as it contains a significant amount of lipids. However, the energy 18 necessary to remove its high water content is a major inconvenience for scaling up 19 because of the high associated cost. In addition, the expensive conventional sludge 20 drying methods are not effective enough for for lipid recovery, thus reducing the 21 potential biodiesel production. This study explores an alternative method, the direct 22 sequential liquid-liquid extraction, which was performed in a batch mixer-settler reactor 23 at room temperature, using hexane as a solvent, after previous sludge acidification 24 showed significant increase in the lipid efficiency. The optimisation study demonstrated 25 that, after three stages, 91% of lipid from primary sludge was recovered. The optimised 26 *Manuscript Click here to view linked References