The paper mill effluents utilised for this study were taken from a modern bleached kraft mill located in western Turkey. Wastewater (4500 m3/h) are discharged into Gökova gulf (Muğla, Turkey) by deep discharging after being collected in sedimentation pools and aerated for a week. The wastewater samples used in this study were taken from aerated logoons right before the sea discharging process. The characteristics of the raw wastewater are given in Table 2.