悬浮区对竖流沉淀效果影响研究

Study on the influence of suspension layer on treatment effect of vertical flow sedimentation

竖流沉淀依靠絮体自然沉淀和悬浮区拥挤沉淀实现固液分离,适度絮凝能充分发挥二者的协同作用,降低药剂投加量,提高沉淀效果。为了明确悬浮区的作用,开展了连续流竖流沉淀试验,考察测试不同工况下絮体的形态、悬浮区状态、沉淀效果等变化规律,重点分析了轻度絮凝、中度絮凝和重度絮凝3个典型的工况。结果表明:轻度絮凝的絮体自然沉降效能和悬浮区拦截效果均不佳;重度絮凝虽然絮体自然沉降效果好,但是悬浮区拦截效果较差;只有中度絮凝可以较好地平衡絮体自然沉降和悬浮区拦截的协同作用,沉淀效果最好,对应的絮体分型维数为1.83,密度为1.391 g/cm^(3),悬浮区高度为2.2 m左右。

Vertical flow sedimentation relies on natural sedimentation of flocs and hindered sedimentation of the sus⁃pension layer to achieve solid-liquid separation.Moderate flocculation could completely leverage the synergistic effect,reduce the dosage while also improve the sedimentation effect.For the purpose of clarifying the significance of the sus⁃pension layer,this paper conducted a continuous vertical flow sedimentation experiment to observe and test the changes in the morphology of flocs,suspension layer state,and sedimentation effect under different operating condi⁃tions.The analysis was focused on three typical operating conditions:mild flocculation,moderate flocculation,and heavy flocculation.The results suggested that the natural settling efficiency of flocs and suspension interception effect under mild flocculation were inferior.Although the natural settling effect of heavy flocculation was outstanding,the in⁃terception effect in the suspension layer was not satisfied.Only moderate flocculation could effectively balance the syn⁃ergistic effect of natural sedimentation and suspension layer interception,with the best sedimentation effect,corre⁃sponding to a floc fractal dimension of 1.83,density of 1.391 g/cm^(3) and suspension layer height of 2.2 m.