Simulation of the operational conditions of the full-scale municipal wastewater treatment plant to improve the performance of nutrient removal

基于数学模型的模拟分析是确定规模化生物脱氮厂运行条件的有力工具之一。该模型包括活性污泥模型2号，是为了模拟札幌市该厂的性能而开发的。该厂生物反应池由厌氧-好氧-缺氧-好氧四个区组成，一级出水分步进水到厌氧区和缺氧区。我们进行了三个实验来校准和验证我们的模型：(I)用我们的测量方法表征反应池进水中的有机物；(Ii)测量工厂的COD和营养浓度；(Iii)实验室规模的批处理实验，包括厌氧-好氧-缺氧-好氧阶段。模型的标定过程表明，不需要修改参数值来评价活性污泥的工厂和种群的性能。模拟结果表明，污水分级进水比的选择不影响脱氮效果，缺氧区的反硝化速率受难降解有机物的水解率控制。小试和模拟结果表明，投加初沉池污泥发酵产物等易生物降解有机物可有效提高脱氮效果。

Simulation analysis based on a mathematical model is one of the powerful tools for determining the operational conditions for a full scale biological nutrient removal plant. The model that included the Activated Sludge Model No.2 was developed for simulating the performance of the plant in Sapporo City. The investigated plant has the biological reaction basin which consists of the four zones, anaerobic-aerobic-anoxic-aerobic phases with the step feed of the primary effluent to the anaerobic and anoxic zones. We performed three experiments to calibrate and verify our model : (i) Characterization of organic matters in the influent of the reaction basin with the OUR measurement method ; (ii) Measurement of COD and nutrient concentration at the plant ; (iii) Lab-scale batch experiments with the anaerobic-aerobic-anoxic-aerobic phases. The calibrating process of the model showed that no modification of parameter values was required to evaluate the performance of the plant and population of the activated sludge. Simulated results showed that the choice of the sewage step feed ratio did not affect the nitrogen removal and that the denitrification rate in the anoxic zone was controlled by the hydrolysis rate of the slowly biodegradable organic matters. The results of the lab-scale experiment and simulation results showed that the addition of the readily biodegradable organic matters like fermentation products of the primary settler sludge was effective to improve the performance of nitrogen removal.