悬浮填料生物反应器处理低浓度氨氮的动力学特性分析

城市污水经一级强化处理后,NH3-N浓度为10~15mg/L,CODCr为40~60mg/L。试验利用悬浮填料床对一级强化处理出水中的氨氮进行深度处理,分析了悬浮填料表面负荷和硝化速率与水力停留时间的关系,并模拟分析了硝化速率与氨氮浓度的关系。结果表明,悬浮填料床内混合液氨氮浓度为0.5~2.5mg/L时,硝化反应符合半级反应动力学,半级反应速率常数k1/2为0.48(g/m)0.5/d;混合液氨氮浓度>2.1mg/L时,硝化反应遵循零级反应动力学,rmax为0.71g/(m2.d)。动力学理论计算值与实际运行结果基本吻合,说明动力学模型对悬浮填料床的硝化性能具有良好的预测和指导意义。

ANALYSIS OF KINETIC CHARACTERISTICS OF TREATING LOW CONCENTRATION NH3-N BY SUSPENDED PACKING BIOREACTOR

The concentrations of NH_3-N and COD_ Cr in municipal wastewater are 10～15 mg/L and 40～60 mg/L respectively after enhanced primary treatment,for which the advanced treatment is done by a suspended packing bed.The relationship between the loading of the suspended packing & nitrification rate and hydraulic residence time is analyzed; and the relation of the nitrification rate to NH_3-N concentration is also simulated.The results show that when NH_3-N concentration of mixed solution is 0.5～2.1 mg/L in the bed the nitrification reaction is the half-order kinetics,whose rate constant (k_ 1/2 ) is 0.48(g/m) 0.5 /d.But if NH_3-N concentration exceeds 2.1 mg/L the nitrification follows zero-order kinetics and τ_ max is 0.71 g/(m2.d).The calculated values agree basically with those of actual operation.