舟山高浊度海水混凝除浊研究

测定了舟山高浊度海水悬浮物的粒度分布,分析了高浊度海水自由沉降特性,选用氯化铁(FeCl)3、聚合氯化铁(PFC)、聚合硫酸铁(PFS)3种混凝剂,利用正交试验方法对高浊度海水进行混凝沉淀对比试验,采用极差分析方法研究了影响混凝效果的因素。试验结果表明:舟山海域悬浮物组成以粉砂为主,用自然沉降的方法是很难去除;各因素对浊度去除率影响的主次顺序均为:慢搅时间>慢搅速度>快搅时间>快搅速度;对于高浊度海水混凝除浊最佳水力条件为:快搅时间为2 min,快搅速度为300 r/min,慢搅时间为15 min,慢搅速度为60 r/min;聚合硫酸铁是较理想的絮凝剂,最佳投药量范围在15～25 mg/L,对浊度去除率高达99%以上。

Study on Removal of Turbidity from Zhoushan High Turbidity Seawater by Coagulation Method

On the basis of investigating the particle size distribution and free settling characteristic of Zhoushan high turbidity seawater,the coagulation and sedimentation experiments were carried out by using FeCl3,PFC or PFS as coagulants,applying orthogonal test method,and the factors affecting the coagulation effect have been studied by range analysis method.The results showed that: silt is main composition of suspended matter in sea area of Zhoushan,which could not be removed only by free settling;the effects of four main factors on turbidity removal rate have been verified as follows: low stirring time>low stirring velocity >fast stirring time > fast stirring velocity;the best hydrodynamic conditions were that fast stirring time and velocity is 2 min and 300 r/min separately,low stirring time and velocity is 15 min and 60 r/min separately;PFS was the better coagulant,and its optimum dosage was 15～25 mg/L,the removal rate of turbidity exceeded 99% correspondingly.