The present paper aims to expose two techniques of dewatering for sludge, analyzing its operations and dewatering processes. It describes the field tests performed on two geotextile systems, a closed geotextile tube and an open geotextile drying bed, both of which are submitted to two filling cycles. The sludge used in the filling cycles for the field trials is from a water treatment plant. Data about height abatement and solids content in time due to the dewatering were collected. With the laboratory analysis of the sludge allied to the data collected in the field, it was possible to perform a comparative study between the two systems. The tests were carried out on three fronts: field tests, including the filling cycles of the systems with the sludge, taking measurements of filling time per cycle and maximum filling height per cycle, heights against the abatement by dewatering of the systems over time; laboratorial tests, including the characterization of the sludge and removal of material samples from the systems to ascertain the solids content within per time and; comparing the data obtained in the field and laboratory tests for the two systems. Through the study, it was possible to perceive that the process of densification inside a closed system, such as the geotextile tube, occurs faster than the observed in the drying bed system. This process of accelerated densification can be explained trough the pumping pressure of the sludge in its filling and by the confinement of the residue through the permeable geotextile membrane, accelerating the process of dewatering by its own weight after filling.
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