Effect of Dissolved Oxygen on Nitrogen and Phosphorus Removal Rate in Biolak Process
In this research, the domestic wastewater was treated by full-scale Biolak/A2O process. The effects of dissolved oxygen (DO) on nitrogen and phosphorus removal of the system in oxic zone were investigated. Controlling to DO at 0.8-1.5 mg/L, the treatment efficiency of system was near optimal with the total nitrogen efficiency of 69.45%. The simultaneous nitrification and denitrification could be achieved under this condition. Based on the calculation equations and transformation pathways of nutrients, about 23.71% total nitrogen (TN) was removed by multistage A/O system in the oxic tank. When DO was 1.0-3.0mg/L, the total phosphorus (TP) removal efficiency was the highest at 73.97%. DO in the range of 1.0-1.5mg/L was optimal for the nutrient removal in Biolak/A2O process, removal efficiency of TN and TP were 68.87% and 73.68%. TN and TP of the effluent were 12.02mg/L and 0.95mg/L, respectively.