Quick start-up of external circulation (EC) anaerobic reactor

The performance efficiency, stability and inner sludge distribution were investigated in the operation of the full-scale EC reactor for brewing wastewater treatment and the key factor to the formation of anaerobic granular sludge was analyzed, which provides the references for the start-up and operation of EC reactor. After operation for 95 d, the influent organic load and removal efficiency were 8.5 kg/(m³ · d) and 80% respectively, and the effluent COD was lower than 400 mg/L. Meantime, the granular sludge with size of 0.5-1.0 mm was observed from the heights of 1.2 and 4 m in the EC reactor. The results demonstrate that EC anaerobic reactor using the intermittent-continuous start-up mode for treating the low COD concentration and high flow of brewing wastewater is feasible and the upflow velocity in range of 2.5-5 m/h is helpful to form granular sludge quickly. The experiment validates that the EC anaerobic reactor can start up stably and efficiently in the brewing wastewater treatment.