Optimization of Nitrate Recirculation Flow and External Carbon Dosage Integrated Control for A/O Biological Nitrogen Removal Process
A/O生物脱氮工艺内循环回流和外碳源投加综合控制的优化

In order to improve A/O process denitrification efficiency, five integrated control strategies of nitrate recirculation flow and external carbon dosage for denitrification were proposed and evaluated using the COST/IWA simulation Benchmark. Results show that control strategy No.1 is the best integrated control strategies from both external carbon consumption, effluent quality, and the stability of controller. It comprises two feedback control loops: one is to determine the flow rate of external carbon source, keeping the nitrate concentration at the end of anoxic zone at a pre-specified level 2 mg/L, and the other is to adjust the flow rates of the nitrate recirculation to keep the nitrate concentration at the end of the aerobic zone at a pre-specified level based on the effluent quality (usually 8-12 mg/L). This strategy can guarantee highly effective use of anoxic denitrification capacity in the low-load condition, and meet effluent discharge standards through carbon dosage in the high-load condition.