The objectives of this study were: (1) to determine the effects of different adsorbents and chemicals on color removal in activated sludge systems, (2) to determine optimum operating conditions and the kinetic constants and coefficients for cotton textile wastewater. For this purpose, optimum operating conditions of a laboratory model activated sludge system were determined and DEC, powdered activated carbon (PAC), bentonite, activated clay and Macrosorb were added under these conditions. The difference between the substances on effluent color investigated using statistical analysis.