城市污水厂A^(2)/O工艺生物脱氮过程优化控制

Optimal Control of Biological Nitrogen Removal in A^(2)/O Process of WWTP

针对城市污水厂运行过程中曝气风机能耗高、外加碳源药耗高的问题,将A^(2)/O工艺中好氧池沿程氨氮浓度、进出水总氮浓度、缺氧池末端出水的硝酸盐氮浓度和COD浓度作为分析对象,进行A^(2)/O生物脱氮过程的优化控制。首先根据好氧池沿程氨氮浓度调节好氧池的曝气量,从而进行硝化过程的优化控制。然后根据进、出水总氮浓度调节系统的内回流比,根据缺氧池末端出水的硝酸盐氮浓度和COD浓度调节缺氧池外部的碳源投加量,从而进行反硝化过程的优化控制。结果表明,采取上述生物脱氮过程的优化控制策略,使得某5×10^(4)m^(3)/d的城市污水处理厂在实际运行中曝气量降低了50%,碳源投加量降低了74%,出水水质仍能达到排放标准。

In view of the problems such as high aeration consumption and high consumption of external carbon source in the operation process of a municipal wastewater treatment plant( WWTP),the ammonia nitrogen concentration along the aerobic tank, the influent and effluent total nitrogen concentrations,nitrate nitrogen and COD concentrations at the end of the anoxic tank in the A^(2)/O process were analyzed as the objects to optimize its biological nitrogen removal process. Firstly,the aeration rate of the aerobic tank was adjusted according to the ammonia nitrogen concentrations along the aerobic tank to optimize the nitrification process. Then the internal reflux ratio was adjusted according to influent and effluent total nitrogen concentrations,and the external carbon source dosage is adjusted according to the nitrate nitrogen and COD concentrations at the end of the anoxic tank. The results indicated that taking the optimal control strategy of biological nitrogen removal process mentioned above,the aeration rate of a5 × 10^(4) m^(3)/d municipal WWTP was reduced by 50% during actual operation,and the external carbon source dosage was reduced by 74%,which can still reach the discharge standards.