Effect of different extra dosing methods on the production of PHA from aerobic granular sludge

To enhance the production of polyhydroxyalkanoates (PHA) by aerobic granular sludge (AGS), the impact of four different extra dosing strategies (no-dosing, aerobic 0h-dosing, aerobic 0.5h-dosing, and aerobic 1h-dosing) on the synthesis of PHA by AGS were investigated. Simultaneously, the removal efficiencies of chemical oxygen demand (COD), total nitrogen (TN) and solubility orthophosphate (SOP) by AGS, along with changes in the microbial community composition were examined. The results indicate that extra dosing of organic carbon positively influenced PHA production, with the highest yield (125.06mg/g) observed under aerobic 1h-dosing condition. Additionally, the nutrient removal efficiency of AGS was influenced by dosing time. When dosing was postponed from aerobic 0h to 1h, TN removal decreased from (87.49 ± 5.49)% to (67.60 ± 16.24)%, and the removal efficiency of SOP decreased from (94.08 ± 1.42)% to (62.91 ± 15.33)%. Notably, under various dosing conditions, the microbial community structure of AGS exhibited significant variation. The dominant bacteria under no-dosing and aerobic 0h-dosing conditions were Acinetobacter, capable of both PHA production and nutrients removal. Conversely, while under aerobic 1h-dosing conditions, Hydrogenophaga and Flavobacterium were the dominant bacteria, specializing in PHA production. © 2024 Chinese Society for Environmental Sciences. All rights reserved.