Applicabilité directe en tube géotextile du procédé de traitement par stabilisation et solidification de boues de dragage hydraulique

Abstract

The development of port activities today in many countries requires the construction of new harbor infrastructures in order to meet growing needs in terms of docking quays, transshipment activities and handling areas. The construction of these new harbor infrastructures will particularly require the dredging of a large volume of sediments or potentially contaminated muds. Stabilization and solidification (S/S) of contaminated sludges were proposed as a treatment solution. The study conducted in this thesis proposes an innovating alternative to the S/S treatment on hydraulic dredging sludges. The direct coupling of the S/S treatment process and the passive dehydration process by geotextile tube is proposed as a feasible solution so as to limit the space required for mud draining and to control the suspended substances rejected into the river while draining. This innovating alternative solution to the S/S treatment could be the direct injection of valuable components (such as cement and polymer) in the conduits during the pumping of the dredging muds towards the geotextile tubes. Two experimental phases were elaborated in the methodological procedure. Phase I aimed at evaluating the performance of the S/S treatment on elutriated muds. The yielded results show that the treated material has a resistance approximates 2 at 5 MPa, a permeability of about 10-9 cm/s, and a mass loss 1% after 56 days of wetting-drying cycles. The chemical characteristics of the material obtained in phase I show metal and PAHs concentrations lower than the values of class 2 according to the Ministry of sustainable development, environment and the fight against climate change (MSDEACC) and Environment Canada (EC) recommendations. Phase II aimed to evaluate with a prototype of sludge pumping system, the performance of the present process on slurries. The evaluation of the quality of the water rejected at the end of the treatment seems to comply with the EC and MSDEACC standards of water rejection. The results of chemical diffusion and leaching tests showed a decrease in the mobility of metals (copper, nickel and zinc). The results of turbidity (31 NTU) and suspended matter (SM) (32 mg/L), show that the process allows the retention of SM in the geotextile tubes and the clarification of the filtration water. Similarly, the results of the physical tests on the material extracted from the geotextile tubes bring some interest in the idea of re-utilizing and a safe valuing of muds as filling material in construction projects.

Date	18 Jul 2018
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Jean-Sébastien Dubé (Supervisor) & Jean Philippe Boudreault (Co-supervisor)