The COD and color of influent, biomass concentration (MLSS), TSS, pH, temperature and dissolved oxygen concentration of the aeration section, as well as COD and color of filtered effluent were measured throughout the experimental program. Prior to color measurement, both the influent and the effluent were filtered through a membrane filter (0.45 μm) to prevent turbidity. Color measurements were carried out with a spectrophotometer. Since the wastewater contains different kinds of dyes (depending on the production), the traditional method of applying the maximum absorbance was not utilized. Color content was determined by measuring the absorbance at three wavelengths (445, 540, and 660 nm) and taking the sum of these absorbencies [4] and [5].