Browsing by Author "Ernest, Dora"

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    Potential of using waste water microalgae as a feedstock for biodiesel production
    (University of Dar es Salaam, 2014) Ernest, Dora
    This study deals with the use of wastewater microalgae biomass as feedstock for biodiesel production. One step transesterification process has been followed in which oil was first extracted from microalgae biomass using Soxhlet apparatus. In this study, Spirulina and Euglena were found to be dominant species in the ponds in which 60-65% (60-65 Cell/ml) were Spirulina; while 30-35% (30-35 Cells/ml) were Euglena. On harvesting 0.297 kg/m2 day of microalgae biomass is possible to be harvested. During biodiesel production process, several factors affecting the final lipid conversion rate were tested and optimized. Oil yield was found to be 11.15% out of 291.67 g of dried icroalgae biomass harvested from 10 liters of wastewater slurry. The moisture content of the dried samples was found to be 11.2%. The amount of free fatty acid and water content of the microalgae oil was found to be 0.43 and 0.94% respectively which were below the limits required which are 1% for free fatty acids and 2.5% for water content. This shows that no further pretreatment of the oil is required before transesterification process. Biodiesel production was done at different temperatures ranging from 27- 68oC in which highest lipid conversion rate of 92.8% occurred at 60oC within 5 hours reaction time, 1.5% (% g NaOH/g lipid) and at 200 rev/min. The physical-chemical and thermo –chemical properties of the biodiesel produced showed that the heating value, density, viscosity and cloud point were 38-41 MJ/kg, 891-897 kg/m3, 3.8-4.8 mm2/s and -10.8 to 11.4oC respectively in which all these properties almost correlate with most of literatures as well as with ASTM standards for biodiesel.