Enhanced phosphorus removal in biological nitrogen and phosphorus removal process using membrane bioreactor

In order to study the effect and characteristics of phosphorus removal in biological nitrogen and phosphorus removal process using membrane bioreactor, this paper investigates the removal efficiency of total phosphorus (TP), and discusses the contributions of biological growth phosphorus removal, denitrifying phosphorus removal, aerobic phosphorus removal, and membrane filtration phosphorus removal. The results show that the average removal efficiency of TP is 92.0%. The phosphorus removal mechanism in this process is different from that in the conventional biological phosphorus removal process in which aerobic phosphorus uptake plays the most important role. In the process, denitrifying phosphorus removal is enhanced and contributed by 34.0%-38.6% in the total phosphorus removal. In addition, membrane can reject a portion of colloidal phosphorus, leading to a further decrease of total phosphorus concentration in membrane bioreactor permeate.