Comparation of nitrogen and phosphorus removal by coimmobilized bacteria-algae system with three kinds of carriers

Three kinds of carriers, including alginate-sodium, polyvinyl alcohol and composite carriers, were used to coimmobilize bacteria-algae system. Chlorella pyrenoidosa and Scenedesmus obliquus as two kinds of algae were used in the experiment. Then bacteria was obtained from activated sludge. Coimmobilized bacteria-algae system, immobilized algae system and immobilized bacteria system were respectively made to treat synthetic wastewater. The results showed that: (1) compared to polyvinyl alcohol and alginate-sodium, bacteria-algae system immobilized by composite carrier had the best nitrogen and phosphorus removal efficiency, and bacteria-algae system immobilized by polyvinyl alcohol had better removal efficiency than that immobilized by alginate-sodium. (2) Coimmobilized bacteria-algae system had better nitrogen and phosphorus removal efficiency than immobilized algae system and immobilized bacteria system, and immobilized bacteria system had lower removal efficiency than the other two. (3) The Chlorella pyrenoidosa immobilized by three kinds of carrier had better nitrogen and phosphorus removal efficiency than Scenedesmus obliquus.