Biodiesel production from algae grown on food industry waste water

Energy crisis is a worldwide problem; Pakistan is facing severe shortage of this, especially in summer. To overcome these crises, huge amount of fossil fuels is being utilized which ultimately resulting in their exhaustion. In order to cope up the increasing energy requirements, alternative energy sources are required that should be cost-effective, environment friendly and technically feasible. In this scenario biodiesel production from algae has attracted scientist's attention worldwide. At present, the major constraint in biodiesel production from algae is nutritional cost for algal growth. Present research work was planned to minimize nutritional requirements of algae by using food industry waste water as a medium for algal growth towards economical biodiesel production. For this purpose four algal strains (A1, A2, A3 and A4) collected from different fresh water sources were evaluated for their potential use in biodiesel production. The waste water was pre-analyzed to determine the concentrations of different nutrients. All algal strains were grown in Bristol media and different dilutions (10, 20, 40, 80 and 100%) of food industry waste water. Growth data was recorded for one week. The results showed that algal biomass gradually decreased with increasing dilution of food industry waste water and was found higher in 100% waste water concentration than other dilutions. Cultivated algae were harvested for biodiesel production with n-Hexane as oil extractant and NaOH as a catalyst in different combinations through a chemical process ca\led transesterification. The FFA (free fatty acid) profile of algae 1 (A1) by using 75% hexane and 0.5% NaOH combination was found to be higher than other combinations. Higher concentration of NaOH (1%) resulted in soap formation. The aforesaid situations, plus owing to the best biomass production using 100% waste water concentration, deemed algae 1 (A1) as the best candidate among all four strains evaluated for biodiesel production.