Ensaios de filtração in loco em geotêxteis aplicados em sistemas de drenagem de base de aterros sanitários

Abstract

Leachate collection systems in sanitary landfills play a crucial role in protecting the drainage layer from clogging, typically employing granular filters or geotextiles. The latter have gained prominence due to their practicality, lower cost, and quality control. However, geotextiles are also susceptible to clogging, particularly because of the high organic load present in leachate generated by the decomposition of municipal solid waste (MSW). In this context, the main objective of this study was to develop and implement a filtration testing methodology that closely reflects real field conditions, using leachate produced under actual landfill operations. Additionally, the study aimed to assess the performance of a geotextile with a large filtration opening (3.10 mm)—a configuration not yet explored in the literature—compared to two conventional geotextiles with openings of 0.15 mm and 0.40 mm. Filtration columns were constructed and operated in the field under two setups: one including the party of the complete system (MSW, geotextile, and gravel), and another without MSW, in order to isolate the influence of the waste on the filtration behavior. The tests were conducted from May 2024 to May 2025, with physical-chemical, microbiological, and microscopic analyses of the percolated leachate and exhumed geotextiles, along with continuous permeability monitoring. The results showed that geotextiles with smaller openings experienced more pronounced clogging effects, with a significant decline in permeability over time. It was observed that clogging mechanisms acted simultaneously but with varying intensities throughout the testing period. In contrast, the geotextile with the 3.10 mm opening demonstrated more stable hydraulic performance and less pore blockage, even in direct contact with MSW. In conclusion, the large-opening geotextile presents itself as a viable and promising alternative for drainage systems in sanitary landfills.