Coupled microalgal cultivation with the treatment of domestic sewage and high-level CO 2 .

The ability of Scenedesmus quadricauda SDEC-13 to accumulate biomass and remove nutrients in domestic sewage from campus when incorporated with 15% CO2 was explored. The maximum specific growth rate, biomass productivity, biomass concentration, and CO2 fixation rate were 0.14 d-1 , 0.08 g/L/d, 0.69 g/L, and 0.076 g-CO2 /L/d, respectively. The lipid content of SDEC-13 at different culture phases was also evaluated and it increased following nutrient limitation. The removal efficiencies of total nitrogen, total phosphorus, nitrate, and ammonium were all above 90%. A coupled system was designed with hydraulic retention time of 8.33 d and biomass harvest ratio of 12%, which could yield 0.54 g/L biomass and 25% lipid content with efficient domestic sewage treatment.