复合调理对淤泥机械压滤脱水特性的影响机理分析

Influence Mechanism of Composite Conditioning of Sludge on Dehydration Performance of Mechanical Pressure Filtration

机械压滤脱水是广泛应用的河湖淤泥脱水工艺,淤泥调理方式是影响机械压滤脱水效率的关键因素之一,采用聚丙烯酰胺(PAM)为代表的絮凝剂调理以及絮凝剂与无机调理剂联用的复合调理是2种典型的淤泥调理措施。复合调理近年来发展迅速,研究絮凝剂单一调理与复合调理对机械脱水效率的影响、探索作用机理,对淤泥机械压滤脱水的工艺优化具有重要意义。以官田湖底泥为试验对象,对比PAM、新型低碱性淤泥改性剂(LAC)的淤泥调理、脱水效果,分析PAM及PAM+LAC复合调理淤泥脱水工艺参数,利用压汞试验与扫描电镜(SEM)揭示复合调理对脱水泥饼结构影响。结果表明,调理药剂的促进作用主要在过滤脱水阶段最显著;LAC具有替代和强化PAM调理效果的作用,改善了泥饼卸料性能;加入LAC有助于维持泥饼骨架结构和增大泥饼孔隙,增加的孔隙以开口孔隙为主。

Dehydration through mechanical pressure filtration is widely used for dehydrating river and lake sludge.The conditioning of the sludge significantly impacts the efficiency of mechanical filtration dehydration.Two common conditioning measures include utilizing flocculant with polyacrylamide(PAM) and employing a compound conditioning approach that combines flocculant with an inorganic conditioner.In recent years,compound conditioning methods have seen rapid development.Studying the impact of single and compound conditioning of flocculants on the efficiency and mechanism of mechanical filtration dehydration is crucial.Focusing on the sludge sourced from Guantian Lake,this study compares the conditioning performance of PAM and LAC and their dehydration performance,and analyzes the dehydration technical parameters in PAM and PAM+LAC conditioning cases.The effect of composite conditioning on the structure of dehydrated sludge cake is also revealed via mercury intrusion test and SEM scanning.Findings indicate that the conditioning agent primarily enhances the filtration and dehydration stages,as evidenced by water loss meter tests aligning well with the plate and frame mechanical filtration press results.The use of LAC as a supplement to PAM can improve the unloading performance of the sludge cake by enhancing conditioning effects.Microscopic analysis revealed that LAC enlarged the pore size of the sludge cake and increased the proportion of open pores.