Integrated campus sewage treatment and biomass production by Scenedesmus quadricauda SDEC-13

• Campus sewage was recycled twice for S. quadricauda SDEC-13 cultivation.
• Nutrients were basically removed and sewage could be discharged on standard.
• Lipid content obtained in twice use of campus sewage were all higher 27%.
• Limited nutrients in campus sewage had no effect on the protein and lipid quality.
• Campus sewage without consuming pretreatment can be utilized directly.

The notion of wastewater treatment combined with biomass production is potential and prospective. Campus sewage was utilized twice in procession to cultivate the newly isolated microalgae Scenedesmus quadricauda SDEC-13. Nutrients was efficiently removed with the phosphorus and nitrogen removal efficiency nearly 100% and more than 70% respectively in twice use of campus sewage. Ammonium was consumed rapidly within five days in 1st use. There was no significant difference in the lipid and protein content but distinct difference in their respective productivity which is ascribed to the lower biomass productivity caused by limited nutrients in 2nd use. The diverse nutrient concentration in twice use of campus sewage and BG-11 had effects on the composition of fatty acids and amino acids. SDEC-13 performed better biodiesel quality compared with BG-11 medium and produced high quality protein when cultivated in campus sewage. Finally, the campus sewage after twice use reached the corresponding discharge standard.