The wastewater reuse is an important way out facing the water resource and energy crisis, and the coupled process of the advanced wastewater treatment and the microalgal energy production is an important issue in this respect. In this paper, the activated sludge as the fixing bacteria is immobilized with Chlorella vulgaris and Scenedesmus obliquus, respectively, for the enhanced municipal wastewater treatment. The microalgal growth, the nitrogen and phosphorus removal and the oil production of the coimmobilized microalgae and bacteria, the immobilized microalgae, and the suspended microalgae are then compared. It is shown that the co-immobilized bacteria and algae are better than the immobilized bacteria and the immobilized algae in their effect on the nitrogen and phosphorus removal, and better than the non immobilized algae and bacteria as well, while the co-immobilized bacteria and algae produce much more lipid. When the concentrations of the NH₄⁺ - N and PO₄^3--P in the municipal wastewater are about 25 mg/ L and 3 mg/L, the NH₄⁺ -N and PO₄^3- -P in the wastewater are removed completely by the co-immobilized Secenedesmus obliquus and bacteria, whereas the lipid yield of C. vulgaris reaches 16.5%.

microalgae  /  nitrogen and phosphorus removal  /  bioenergy