A dynamically controlled anaerobic/aerobic granular sludge reactor efficiently treats brewery/bottling wastewater

Abstract

This study investigated the application of a dynamic control strategy in an aerobic granular sludge (AGS) reactor treating real variable brewery/bottling wastewater. For 482 days, the anaerobic and aerobic reaction steps in a lab-scale AGS system were controlled dynamically. A pH-based control was used for the anaerobic step, and an oxygen uptake rate (OUR) based control for the aerobic step. Additionally, the effect of an elongated aerobic step, and the effect of the removal of the suspended solids from the influent, on AGS formation were also investigated. In comparison to a static operation, the dynamic operation resulted in similar reactor performance, related to effluent quality and the anaerobic dissolved organic carbon (DOC) uptake efficiency, while the organic loading rate was significantly higher. The removal of suspended solids from the influent by chemical coagulation with FeCl3 turned hybrid floccular-granular sludge into fully granular sludge. The granulation coincided with a significant increase in the abundance of the glycogen-accumulating Candidatus Competibacter and an increase in the content of gel-forming EPS to respectively around 14% and 30%. In conclusion, this study showed the successful application of a dynamic control strategy based on common and low-cost sensors for AGS treatment of industrial wastewater. HIGHLIGHTS Successful granulation in a dynamically operated anaerobic/aerobic AGS system.; Complete granulation with a low hydraulic selection pressure (<0.13 m/h).; The dynamic control of the anaerobic phases was based on the pH profile.; The dynamic control of the aerobic phases was based on the OUR profile.; The dynamic control strategy coped with industrial brewery/bottling influent.;

Keywords

• aerobic granular sludge
• dynamic control
• glycogen accumulating organisms (gao)
• industrial wastewater
• oxygen uptake rate (our)
• ph