Paper industry is considered one of the major industry especially in Egypt. National paper company [NAPA] which produces many types of paper was selected in this study. It uses - 25000m% d of fresh water and discharges ~ 18000 m% of wastewater into Abu Kir Bay. The waste is characterized by high values of COD, BOD and SS [1650 mg/l, 630 mg/l and 965 mg/l respectively]. So, the aim of this study is to treat the NAPA mill waste to comply it with the law 4/1994 that govern its discharge. The treatment involves primary sedimentation, followed by biologically treatment and then finally clarification. The primary clarifier achieved ~ 83% of SS, 71% of COD and 68% of BOD removal after 2.5 hr sedimentation time. The sludge resulting from the clarifier was fractionated and ~ 63% of it was recycled as a useful fiber. The clarified effluent is then treated biologically using activated sludge at different hydraulic retention time [HRT] and different F/M ratio. The system achieved ~ 95% COD removal and 93% BOD at HRT 8 hr., F/M ratio ranged from 0.22 to 0.29 d-1 and after clarification for 1.5 hr. The characteristics of the final clarified treated effluent are below the permissible limits of the environmental law [4/1994).