Dewatering of dredged slurry by horizontal drain assisted with vacuum and flocculation

Abstract

This study proposes a new method using the combination of flocculation and prefabricated horizontal drain (PHD) assisted with vacuum pressure for rapid dewatering of high-water-content dredged slurry. First, to demonstrate the superiority of using PHD over the more commonly used prefabricated vertical drain (PVD), experiments were conducted to compare the dewatering performance between the PHD and the PVD. Then six model tests with the proposed dewatering method were performed with various contents of flocculant (anionic polyacrylamide (APAM)) to investigate the effect of APAM content on the dewatering process and soil properties (i.e. undrained shear strength, permeability and compressibility). Furthermore, particle size distributions of the slurry before and after model tests were measured to analyze the dewatering behavior and changes in material properties. Finally, particle loss during vacuum consolidation for various APAM contents were compared to study the flocculation effect on clogging problem. Results indicate that the proposed method can prevent significant bending deformation of the drain board and mitigate clogging of the drain filter and, thus, can significantly accelerate the dewatering process of high-water-content dredged slurry.

Research on closed-loop utilization of engineering waste mud in engineering sites

“…If PAC and APAM are used together, they will have a positive superposition effect on the performance of solidified soil. For example, the unconfined compressive strength and softening coefficient of the fluidized solidified soil in sample 5 can be increased by 25% and 34%, respectively, To further demonstrate the strengthening effect of the combined flocculants on fluidized solidified soil from the microstructure, SEM and XRD were used to observe the fluidized solidified soil without flocculants (1) and the fluidized solidified soil containing the combined flocculants (5). The results are shown in Figure 9.…”

“…Additionally, because of progress in the development of environmental protection, much research is conducted with the aim of prolonging the operation time of machines in direct contact with the materials used in waste recycling, e.g., metal shredder blades, transportation containers, and so forth. [5]. Excessive wear of machine parts negatively affects the entire production and technological process.…”

“…At present, the main effective reduction treatment method for engineering waste mud uses * E-mail: 997124222@qq.com dehydration to reduce water content and external displacement [5][6][7]. The main dehydration methods include mechanical pressure filtration dehydration [8,9], direct solidification dehydration [10,11], and flocculant precipitation dehydration [12,13], but mechanical pressure filtration has high mechanical requirements and low treatment efficiency.…”