Modeling Dissolved Oxygen Effects on Biological Nutrient Removal in a Sequencing Batch Reactor with Activated Sludge Model 2d

The simulation software developed by C++ Build language based on activated sludge model 2d (ASM2d) was carried out to address the effects of dissolved oxygen (DO) on the behavior of biological nutrient removal in a sequencing batch reactor (SBR) system. Changes of COD, nitrogen and phosphorus concentrations could be reliably predicted according to the time arrangement of every phase adapted to the SBR conditions. Better performance of biological nutrient removal could be achieved as long as DO concentration was above 1.5 mg/L. If DO concentration was at a low level <1 mg/L, the growth and activity of microbes would be inhibited, especially for nitrifying organisms and phosphorus accumulating organisms (PAOs). Consequently, the nutrient removal performance of the process would be affected significantly. Therefore, maintaining DO concentration above 1.5 mg/L in the SBR activated sludge system was adaptive.