Permeabilidade de misturas de solos utilizados em camadas de base de um aterro sanitário

Abstract

Faced with the problem of generating urban solid waste, the search for efficient alternatives for the destination of this waste has become a great challenge. Sanitary landfills present themselves as an economically viable alternative, of simple operation and that minimize the environmental impacts generated by the residues. However, in order to use this solution, it is necessary that the by-products generated during the biodegradation of waste do not contaminate the soil and groundwater. For this, sanitary landfills must be waterproofed with base layers, which have a low permeability to the point of preventing the flow of these contaminants. Thus, the objective of this work is to analyze the variation of permeability in soil mixtures to be used, in cells of the Landfill of Campina Grande in Paraíba. For that, tests of geotechnical characterization were carried out with samples of natural soil of the region added of bentonite in 5%, 15% and 25% of the mass of the mixture. In addition, the permeability test was carried out at variable load, to verify the permeability of the soil, under confinement and saturation conditions. The experimental area was the Landfill of Campina Grande, with the natural soil coming from the landfill region and the bentonite, from a deposit in the municipality of Boa Vista. Thus, it was found that the sample with a bentonite content of 5% presented a permeability coefficient of the order of 10 -7 cm/s (ten to less than seven centimeters per second), with the addition of bentonite being almost irrelevant to its behavior. The 15% sample, even being characterized as sandy soil, presented a permeability coefficient of the order of 10 -8 m/s (ten to less eight centimeters per second), an acceptable value by NBR 8413. presented as a clayey material and its permeability coefficient was 9.9x10 -9 m/s (ten to minus nine centimeters per second). In view of these results, it is possible to state that the mixture containing 25% bentonite content is the most suitable to be used as a base layer of the landfill, considering that it meets all national and international standards, and its use can still be justified by other studies, which prove the need for layers with these characteristics.