The UASB reactor was applied for biodegradation of organic compounds in coking wastewater. The influent pH ranged between 6.8 and 7.2, and stirring speed and temperature were controlled at 2 r/min and 30±1°C, respectively. The reactor was successfully started up in 133 days. When the influent COD was 2,600 mg/L (VLR was 2.6 kg/m3 d), the removal rate of COD was about 54% and the effluent VFA was below 400 mg/L. GC/MS analysis indicated that the coking wastewater mainly contained aniline, phenol, o-phenol, p-cresol, benzoic acid, indole, quinoline etc. Twenty four kinds of organic compounds were detected in the influent, and 20 kinds of organic compounds were completely removed in the UASB reactor. The biodegradation of organic compounds followed Grau second-order kinetics. It was proved to be an effective and feasible method for coking wastewater anaerobic treatment.
Keywords: coking wastewater, GC/MS, start-up, UASB reactor