Application of effluent from WWTP in cultivation of four microalgae for nutrients removal and lipid production under the supply of CO2

The application of effluent from wastewater treatment plant in cultivation of four microalgae under the continuous supply of CO2 was evaluated in a photobioreactor. The results exhibited that Scenedesmus obliquus (S. obliquus) had the highest biomass value (0.76 g L−1), followed by Chlorella pyrenoidosa (C. pyrenoidosa) (0.71 g L−1) and Scenedesmus dimorphu (S. dimorphu) (0.58 g L−1), lowest by Chlorella vulgaris (C. vulgaris) (0.36 g L−1). The TN and TP in the effluent all experienced a sharply decreasing trend. The ratio of consumed N versus P is varying within the cultivation of microalgae, strongly related with microalgae species. No significant difference was found for the amount of N consumed among the four microalgae, but C. vulgaris had the quickest P consumption during the first 2 d. S. dimorphu had the highest lipid content (30.8%), followed by C. vulgaris (29.1%) and C. pyrenoidosa (24.4%), S. obliquus lowest value (17.0%). No significant difference was observed about the CO2 removal rate for four microalgae, but S. obliquus had highest carbon fixation rate of 0.27 g L−1 d−1.