The partially granulated sludge in bio-ferric process has good sedimentation effect, which can provide the returned sludge with higher concentration, and thus increasing the sludge concentration in aeration tank.

• 部分颗粒化的生物铁污泥沉降效果好,能保证系统有较高浓度的回流污泥,从而提高了曝气池的污泥浓度。