摘要
Biodiesel is one of those renewable fuel sources developed to fuel transportation sector to replace conventional petroleum based fuels. In the present work the key concentration is directed towards highlighting engineering and biological issues to resolve the production of biofuels from microalgae to become an economic reality. This study discusses the unit processes required for algal biofuels production in municipal wastewater (i.e. growing the algae, harvesting, dewatering, extraction and conversion to biofuel) and their scalability. The economic estimation in this article is classified as a ‘‘study estimate’’ which had a range of expected accuracy from 30% to −20%. The comparison between Microcystis aeruginosa grown in lab scale and microalgae grown in the oxidation pond system demonstrated that a mixed culture of algae species could successfully be grown on wastewater nutrients and potentially scaled to commercial production. Spirulina maxima was the most dominant species of microalgae in samples collected from Matrouh wastewater treatment plant, and responsible for the over growth detected in the maturation bond. Extracted oil from both Spirulina maxima and Microcystis aeruginosa was transesterified to evaluate the fatty acid methyl ester produced and to identify the purity of the biodiesel. Complete process simulation was carried out using a process simulation software. Assuming that the rate of biodiesel production needed was 10,000 t/year, all process units required have been sized. Total capital investment, total manufacturing cost and return on investment (ROI) were all estimated. The ROI of Spirulina maxima case equaled to 86.92%, while in case of Microcystis aeruginosa was −56.5%. So, the biofuel production from Spirulina maxima grown in wastewater treatment plants is being economically feasible.