Effect of polymer conditioning on dewatering characteristics of fine sediment slurry using geotextiles Available to Purchase

Results from laboratory investigations for evaluation and enhancement of the dewatering performance of fine silt slurry are presented. These experiments were conducted with and without polymer conditioning of the slurry. One type of soil and five types of geotextile were used. The optimal dewatering conditions were investigated using one woven geotextile. An innovative methodology is proposed for determining optimal dewatering considerations using a combination of simple bench-scale tests (jar sedimentation test, jar test, and pressure filtration test). The current state of practice utilises a trial-and-error approach heavily dependent on operator judgement, and ignores the role of the geotextile and the simulation of field mixing conditions. The proposed methodology provides a rational method to determine the optimal dewatering conditions in terms of dewatering time and amount of piping under anticipated field conditions. This novel approach guides the selection and evaluation of candidate polymers, which can be further evaluated in greater detail using pilot-scale tests. It is demonstrated that considerable enhancement can be achieved in the dewatering performance through polymer conditioning. Based on the results of this investigation, it is demonstrated that optimal dewatering conditions (maximum filtration efficiency and minimum dewatering time) can be arrived at with the methods proposed here.