混凝沉淀工艺深度处理污水厂二级出水的混凝剂优化

通过烧杯试验，确定了采用混凝、沉淀工艺深度处理城市污水处理厂二级出水时，最佳的混凝剂组合及投量。结果表明，铝盐混凝剂与PAM组合使用时比铁盐混凝剂与PAM组合使用时的处理效果更好，当PAC＋PAM的组合投量为20mg／L＋5mg／L或30mg／L＋1mg／L、硫酸铝＋PAM的组合投量为30mg／L＋5mg／L时，混凝、沉淀出水浊度为2．5～3．5NTU，COD为25-40mg／L，TP为0．06-0．12mg／L。由于混凝后水中所形成的絮体较小，难于沉淀，因此混凝沉淀工艺对SS的去除效果较差，实际工程中可考虑增设过滤单元。

Coagulant Optimization of Coagulation and Sedimentation Processes for Advanced Treatment of Secondary Effluent from Municipal WWTP

The optimal coagulant combination and dosage during use of coagulation and sedimentation processes for advanced treatment of secondary effluent from municipal WWTP were determined by a jar test. The results show that the combination of aluminum salt coagulant and PAM has higher treatment efficiency than the combination of iron salt coagulant and PAM. When the combined dosage of PAC and PAM is 20 mg/L and 5 mg/L or 30 mg/L and 1 mg/L, and the combined dosage of aluminum sulfate and PAM is 30 mg/L and 5 mg/L, the effluent turbidity, COD and TP are 2.5 to 3.5 NTU, 25 to 40 mg/L and 0.06 to 0.12 mg/L respectively. Because flocs produced from the coagulation process are small and difficult to be sedimentated effectively, the removal efficiency of SS is poor. Therefore, consideration can be given to the addition of a filtration unit in engineering application.