Effect of adding GAC to SBR system for treatment of wastewater contains a reactive dye

Reactive dyes cannot be easily removed by conventional aerobic biological treatment systems. In this study, the effect of adding granular activated carbon (GAC) to sequencing batch reactor (SBR) on treatability of a wastewater containing a reactive dye (Brill Blue KN-R) were investigated. Four cylindrical Plexiglas reactors run for 68 days (5 days for acclimatization of sludge and 63 days for normal operation in two separate phases).In all reactors, effective volume, influent wastewater flow rate and sludge retention time were 5.5 L, 3.0 L/d and 10 d, respectively. Initial dye concentrations were adjusted to be 20, 25, 30 and 40 mg/L in the reactors R1, R2, R3 and R4, Respectively. Constant concentration of GAC (1000 mg/L) was added to SBRs after 36 days operation. According to the obtained data, dye removal efficiencies were increased significantly by adding GAC to SBRs. The average dye removal efficiencies of R1, R2, R3 and R4 were increased 23, 23.6, 18.7 and 18 percent, respectively after adding GAC to SBR reactors. Additionally, no significant changes on average COD removal efficiencies were observed. Average SVI of all reactors was slightly decreased by adding GAC. The average SVI of all reactors before and after adding GAC was in the range of 37- 49 mL/g and 27- 43 mL/g, respectively.