Startup and performance of full-scale anaerobic granular sludge blanket reactor treating high strength inhibitory acrylic acid wastewater

High strength inhibitory wastewaters from chemical industries are commonly treated by energy-intensive physicochemical methods. The present work examines the startup and performance of a full-scale anaerobic granular sludge blanket (GSB) plant for treatment of an inhibitory acrylic acid wastewater. From a performance test on chemical oxygen demand (COD) loading up to 9800 mg/L and 3074 kg/d, the GSB plant removed 95% of COD. Coupled with a two-stage aerobic effluent polishing unit, the integrated anaerobic-aerobic plant achieved a remarkable total COD removal of 98–99% at full design load. Final effluent ranging from 173 to 278 mg COD/L conformed to the public sewer limits of 500 mg/L. Acclimated microbes and granulation resulted in efficient degradation of the inhibitory wastewater. Adequate reactor and process designs are crucial for granulation and robust treatment. The anaerobic and aerobic processes complement each other as anaerobic prime degrader and aerobic polisher in the integrated processes.