Effects of some operating parameters on the efficiency of a sequencing batch reactor system for treatment of textile wastewater containing acid dyes

Abstract

Abstract The purpose of this research was to find the optimal treatment conditions of a sequencing batch reactor (SBR) system for treatment of various types of textile wastewater (TWW) and synthetic textile wastewater containing acid red 18 and acid blue 9 dyes. Experiments were carried out under various BOD5:TN ratios of 100:5, 100:10, 100:15, and 100:20, with mixed liquor suspended solids of 3,000 mg/L, and at hydraulic retention times (HRT) of 5, 7.5, and 10 d in order to determine the highest removal efficiency. Also, glucose, starch industrial wastewater (SWW), and noodle industrial wastewater were tested for their suitability as a carbon source. The results showed that mixed acid dyes had no significant effect on heterotrophic bacteria, but strongly repressed denitrifying bacteria activity. The SBR system with two times diluted TWW containing 1,480 mg/L glucose demonstrated high removal efficiencies for color, chemical oxygen demand (COD), biochemical oxygen demand (BOD5), and TN (75.9 ± 2.1, 89 ± 7...