The study aims to focus on the problem of excess nutrients in the discharges of treatment depends on the use of alum, or so called aluminum sulfate water. Al₂(SO₄)₃ 18H₂O one of the materials used in the coagulation in the removal of phosphates and from the wastewater and by adding alum directly to the aeration tank through biological treatment process-based on continuous flow Activated sludge with different dose (150, 200, 250 mg / L). A comparisons Has been drawn between two basin to find the efficiency of removal the first without adding alum and the second was adding Alum at different Dose. The results showed the efficiency of alum in improving the removal of phosphate significantly since arrived removal efficiency to 98% at doses of 250 mg / L and improving the properties of sedimentation .and its not affected widely on the efficiency removal of the BOD. As the pH values decreased gradually but did not affect the efficiency of removal in the basin of the treatment. Changing has been happened on the properties of the sludge in the basin as sludge change color to White and Milk after adding alum. The study proved the possibility of using alum in the treatment to improve the properties of discharges.