采用沉淀池排泥水回流的方法以强化净水厂低浊水混凝处理效果,进行了影响因素的研究,并应用于实际工程中.结果表明,当原水浊度在5～10 NTU,pH在8.0左右,回流排泥水浊度为281.2 NTU,回流体积比为5％,PAC投加量为18 mg/L时,浊度去除效果最好.在低投加量的情况下,回流排泥水后,除浊效果较为明显,可较大程度的节约投加量.该技术在孝感某水厂运行效果良好,每年可产生至少约150.96万元的经济效益.“,”Sludge water reflux in the sedimentation tank was applied to enhance the flocculation effect of low-turbidity water in water treatment plants.Influencing factors were investigated and this approach was applied in the practical projects.The results showed that the effect of the turbidity removal was optimal when the turbidity of the raw water was between 5～10 NTU,the pH was about 8.0,the turbidity of the returned sludge was about 281.2 NTU,the sludge reflux volume ratio was 5％ and the dosage of PAC was 18 mg/L.Under the circumstance of low chemical dosage and returning sludge,the effect of turbidity removal was obvious,which could greatly save coagulant dose.The technology had achieved good operating results in the second phase of a water plant in Xiaogan,which produced at least 1.509 6 million yuan economic benefits annually.