Fig. 1 shows that COD, which was present as acetate, was constantly being removed from the synthetic wastewater according to the influent and effluent analysis.
The system also demonstrated a remarkable potential of nitrification as well as phosphate removal during a steady-state cycle at 30°C, 40°C and 50°C. Throughout the anoxic feeding phase, cycle profile measurements revealed that acetate was utilized to 34.15% in SBR30, 51.22% in SBR40 and 38.79% in SBR50.
Simultaneously, phosphate was released during the anoxic feeding phase. Subsequently, the rest of the acetate was utilized in the period of aerobic cycle while phosphate was removed. The removal efficiency for the biological phosphorus improved gradually during the aerobic phase and achieved an average removal rate of 72.46% at 50°C, followed by 68.50% and 67.00% at 30°C and 40°C, respectively which is comparable to previous study by Ebrahimi et al. (2010) in treating synthetic wastewater using biogranules.