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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.

Treatment of rapidly varying wastewaters in anaerobic/aerobic 21 aerobic granular sludge (AGS) systems remains problematic. This 22 study investigated AGS formation and the impact of varying COD 23 and phosphorus concentrations on an enhanced biological 24 phosphorus removal (EBPR) AGS SBR with a conductivity based 25 anaerobic and OUR based aerobic dynamically controlled step. 26 Phase 1 investigated the development of AGS. Phase 2 examined 27 the flexibility of the dynamic control strategy and AGS efficiency while 28 rapidly altering the influent composition. AGS was formed 29successfully in phase 1: the DV50 increased to 285 µm., and the 30 SVI5 and SVI30 decreased to 51 and 40 ml/g respectively. In phase 31 2 the effluent COD and PO4-P concentration remained low at 32 respectively 58 ± 27 mg/L and 0.53 ± 0.77 mg/L. With an anaerobic 33 DOC uptake efficiency of 98.4 ± 0.9 %.

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