Wastewater treatment using algae and utilization of grown biomass for bioethanol production

Abstract

The rise in fossil fuel price as well as the concern over environmental impacts caused by the usage of fossil fuel has led to the research and developmentof more sustainable renewable fuels Bioethanol derived from renewable biomass rich in carbohydrate is recognized to be an alternate way thus many attempts to harness bioethanol was carried out recently However usage of sugar and starch materials as feedstocks for producing bioethanol causes major competition with food market as well as the land for cultivation which makes the sources economically less feasible Hence the use of microalgae as a feedstock for bioethanol production has been proposed owing to the presence of huge amount of carbohydrates in the physiology of the microalgal cell Cultivation of carbohydrate rich microalgae coupled with the wastewater treatment creates the process more eco friendly and economically feasible Hence it is necessary to explore the adaptability of microalgae in wastewater treatment In this study Scenedesmusabundans and Chlorella vulgaris were cultivated in municipal wastewater using 5 L transparent polypropylene photobioreactor supplemented with 2 5 CO2 in air mixture Initially the algae were grown in synthetic laboratory media and was acclimatized to the corresponding wastewater When assessed for microalgae growth in wastewater the biomass concentration of both the species peaked at Day 8 during exponential growth which declined later However C vulgaris showed superior growth of 3 6 g L as compared to S abundans 3 45 g L To understand the growth rate of two microalgae the different kinetic models such as Logistic model modified Gompertz model and Richards model were fitted with experimental data newline