Characterization of biodiesel produced from microalgae grown on fish farm wastewater

Abstract

This project investigated the influence of fish wastewater nutrients on properties of fatty acid methyl esters (FAME) of three microalgae species (Tetradesmus obliquus, Heterochlorella luteoviridis and Chlamydomonas reinhardtii) cultivated in unmodified and modified fish farm wastewater (FFW). The fuel properties obtained from the FAME of microalgae cultivated in FFW were then compared to the fuel properties obtained from FAME of the same microalgae species cultivated in a standard growth media of modified tris-acetate-phosphate. FFW nutrients supported the accumulation of desirable biodiesel fatty acids. C16–C18 were the main fatty acid component in all samples making up to 95%. All samples had saturated fatty acids above 22% and over 60% unsaturated fatty acids. Fuel properties of biodiesel produced from microalgae species cultivated in FFW were similar to fuel properties of biodiesel from the same species cultivated in the standard growth media. When compared to ASTM D6751-02 and EN 14214 biodiesel standards, biodiesel from FFW had desirable fuel properties (cetane number, kinematic viscosity, density, higher heating value, cold filter plugging point and iodine value). Overall, Chlamydomonas reinhardtii (in both FFW media) had the most suitable biodiesel property, especially when looking at the cold filter plugging point.