Dewatering of reservoir sediment slurry using woven geotextiles. Part I: Experimental results

A series of falling-head dewatering column tests (FHDT) was performed using a mixture of water and reservoir sediment and four types of woven geotextile to investigate the factors that control the permeability and piping of underdrainage dewatering systems such as geotextile containers and dewatering ponds. Some conventional criteria for the filter selection were also examined. It was found that the permeability of the geotextile dewatering system is characterized by the thickness and the void ratio of the filter cake that progressively deposits upstream of the geotextile. The filter cake exhibited a normally consolidated state with a compression index of 0.7, and the height of the potential filter cake can be predicted based on the total suspended solids and the void ratios measured in the present study. It was also found that the conventional soil retention and clogging criteria should be reformulated for the geotextile dewatering system to take into account some fundamental aspects of the system that were ignored in these existing criteria.