PAC was added into the activated sludge system at 100, 200 and 400 mg/L doses. As an average the best color removal efficiency (86%) was obtained at 400 mg/L. For the addition of 200 mg/L PAC, the color removal efficiency was 77% and for 100 mg/L, it was 65%. However, the increase of TSS concentration due to PAC addition was extremely high, resulting in high sludge volumes.