疏浚泥浆多级絮凝效能与絮体图像特征分析

Analysis of image characteristics of multistage flocculation efficiency and floc morphology of dredged sediment

【目的】在水库疏浚工程中,亟须对产生的高含水率泥浆进行有效处理,故通过试验研究探索出一种泥浆多级絮凝的最佳方案,以实现泥浆快速高效脱水的目的。【方法】对有机高分子絮凝剂聚丙烯酰胺(polyacrylamide,PAM)、壳聚糖(chitosan,CTS)单掺及其与明矾-聚氯化铝(alum and polyaluminum chloride,KAl(SO 4)2-PAC)无机絮凝剂组合进行对比研究,分析不同工况下PAM、CTS多级絮凝的去浊效果、形态特征与絮凝机理。【结果】PAM方案四级絮凝达到了最佳效果,此时上清液浊度降低至1.6浊度值(nephelometric turbidity unit,NTU),粒径大于1000μm的成像面积占比达95.82%,且分形维数达到最大值1.786,生成的絮体形态规则且呈团聚状,为最佳絮凝方案;多级絮凝机理分析结果表明,多级絮凝方式可以有效提升絮凝效能。【结论】本试验成果可为疏浚工程絮凝过程中实现自动控制提供理论依据。

[Objective]In the reservoir dredging project,it is urgent to effectively treat the high water content sediment,so an optimal scheme of multistage flocculation of sediment was explored through experimental research,in order to achieve the purpose of rapid and efficient dehydration of sediment.[Method]The organic polymer flocculant polyacrylamide(PAM),chitosan(CTS),and alum and polyaluminum chloride(KAl(SO 4)2-PAC)inorganic flocculant combination were compared to analyze the turbidity removal effect,morphological characteristics and flocculation mechanism of PAM and CTS multistage flocculation under different working conditions.[Result]The PAM scheme achieves the best effect of four-stage flocculation.At this time,the turbidity of supernatant is reduced to 1.6 nephelometric turbidity unit(NTU),the image area with particle size greater than 1000μm accounts for 95.82%,and the fractal dimension reaches the maximum value of 1.786;the flocs formed are regular and agglomerated,which is the best flocculation scheme;the results of multistage flocculation mechanism analysis show that the multistage flocculation method can effectively improve the flocculation efficiency.[Conclusion]The experimental results can provide a theoretical basis for the realization of automatic control in the flocculation process of dredging engineering.