Integrated aquaculture wastewater treatment and biodiesel production using mixed algal consortia

Abstract

This study investigates the feasibility of integrating the process of waste treatment into aquaculture facilities, and biodiesel production can be achieved using multiple algae species. A mixed consortium consisting of Anabaena sp., Chlorella sp., together with Oscillatoria sp., Oedogonium sp., and Scenedesmus sp., was grown in untreated aquaculture wastewater for 15 days alongside F/2 synthetic medium cultivation. The combined system outperformed by effectively eliminating total nitrogen by 90.5% and removing total phosphorus along with orthophosphate at 100% and achieving 91.1% and 76.8% removal of nitrate and nitrite, respectively. Biomass production reached 7.3 g/L during wastewater-based cultivation, which doubled the results obtained from the F/2 control. The wastewater-grown cells accumulated lipids corresponding to a weight fraction of 43.9%, which generated 3.20 g/L lipid production. After the transesterification process, biodiesel yield matched the lipid yield (3.20 g/L), which produced an 81% greater output than in synthetic media. Laboratory tests on fatty acid methyl ester (FAME) composition showed high levels of palmitic acid (C16:0) and oleic acid (C18:1) that met all international biodiesel specifications according to ASTM D6751 and EN 14214. The research verifies how mixed microalgal cultures promote simultaneous water purification with sustainable biodiesel outcomes. A unified method publishes bioeconomy circularity through the conversion of aquaculture wastewater into renewable energy materials while it improves both aquatic farming sustainability together with operational energy efficiency.