Removal of nitrogen and phosphorus from piggery wastewater effluent using the green microalga scenedesmus obliquus

Piggery effluent is one of the most highly produced wastewaters throughout the world, containing high levels of inorganic nutrient species. In this study, a microalga Scenedesmus obliquus YSW-14 (S. obliquus) was employed not only for nutrient removal from piggery wastewater effluent but also for lipid accumulation in the algal biomass as a feedstock for biofuel production. The piggery wastewater effluent was diluted up to fivefold with synthetic media to reduce the toxicity of (in)organic components, which resulted in improved microalgal growth, nutrient removal, and lipid productivity. Among the examined culture conditions, a 40% concentration of wastewater effluent was found to be most effective for microalga lipid productivity (0.13 mg L-1). S. obliquus removed 155 mg total nitrogen and 4 mg total phosphate per gram of dried algae for growth at the same dilution condition. These results demonstrate the feasibility of using microalgae for advanced wastewater treatment and subsequent production of lipids as biofuel feedstock.