Zou et al. [7] found that anaerobic
phosphorus release rate declined as soon as
NO3− -N was added to the anaerobic zone, resulting in
low phosphorus removal efficiency. Kazmi et al. [8]
modeled the remaining NO3− -N shock on phosphorus
removal, and showed that with the increase of remaining
NO3− -N from 10 mg·L−1 to 20 mg·L−1, the low phosphorus
release in the anaerobic zone would be inhibited
completely and the TP content in the effluent was
much higher than before.