Dewatering rate of vacuum tube filter (VTF)-system-treated sand–clay mixed slurry

Abstract

Vacuum dewatering methods are widely used to treat high-moisture dredged sludge; however, significant particle migration problems exist during treatment, particularly for sand–clay mixture slurries. A dewatering technology called a vacuum tube filter (VTF) system is proposed herein to alleviate the particle migration problem of sand–clay mixture slurries. First, four sets of model tests were performed using the VTF system and conventional vacuum (dewatering) method (CVM, i.e., a prefabricated strip-shaped drain assisted by vacuum) with two types of sand–clay mixed slurries. The water content distribution, settlement, and discharged water from the VTF system were compared with those from the CVM. The VTF system was superior to the CVM in terms of the dewatering rate and effect. Moreover, the particle migration problem was theoretically analyzed using a consolidation solution. With both slurries, the VTF system exhibited a lower particle-migration-problem-induced clogging effect. Thus, the VTF system can effectively alleviate the particle migration problem and enhance the dewatering of high-moisture sand–clay slurries.