Desempenho hidráulico de camada de solo compactado utilizada em aterro sanitário incrementada com biopolímeros

Abstract

Waterproofing the base of landfills is essential to prevent contamination of soil and groundwater. However, many local soils do not have the ideal permeability required by technical standards, which justifies the search for alternatives to improve their properties. In this context, this study evaluated the hydraulic performance of a biopolymer developed from a mixture of Copernicia prunifera (carnauba) and Opuntia ficus-indica (forage palm) powder in comparison to guar gum, applied to soil collected at the Crateús-CE dump. Physical characterization, compaction, permeability and free expansion tests were carried out in order to understand the properties of soil-biopolymer mixtures. The results indicated that the 5% increase in biopolymer made from palm and carnauba increased the soil consistency limits, in addition to reducing the maximum apparent dry mass (𝜌d.max) of the local soil from 1.90 (g/cm3 ) to 1.77 (g/cm3 ) and increasing the optimum humidity (Wotm) from 13.7% to 15.20%. As for permeability, there was an increase of 34% with the increment, varying from 4,63×10-7 (m.s-1 ) to 1,36×10-6 (m.s-1 ), making it unsuitable for application in landfill waterproofing layers without prior treatment. The soil expansibility index, evaluated for both water and leachate, did not show significant changes with the increase. The low resistance to degradation of the biopolymer in contact with water was a limiting factor, suggesting the need for improvements, such as cross-linking processes, to enable its use in layers of compacted soil for waterproofing landfills.