This work describes the application of a yeast biosurfactant in the removal of heavy metals and petroleum derivate in a soil used as slurry barrier using a triaxial permeability apparatus. Test specimens were prepared with soil and contaminants for percolation of the biosurfactant. The hydraulic conductivity measured along percolation of the fluids showed that the biosurfactant reduced significantly the soil permeability, demonstrating its applicability as an additive in reactive barriers. The crude biosurfactant removed around 96% Zn and Cu and reduced the concentrations of Pb, Cd, and Fe from the test specimen. The biosurfactant removed 20% of the waste oil using the permeability apparatus. The results show that the biosurfactant can be applied in new technologies where the removal of heavy metals and petroleum derivates is desirable. These results demonstrate the versatility of biomolecules with amphipathic nature, a property that makes them increasingly competitive with real possibilities for use in industries.

AVALIAÇÃO DO ÂNGULO DE ATRITO SOLO-MURO E DA RUGOSIDADE DA SUPERFÍCIE DE CONTATO

Expansive clay soils are a problem for agriculture and engineering because they are susceptible to change in volume due to seasonal variation in water content and temperature. One of its morphological properties is slickensides, which result from the ability to contract and crack when dry and expand by wetting. The objective of this study was to evaluate the processes of expansion and formation and propagation of cracks due to the change in water content over time. The expansion process [...] ABSTRACT Expansive clay soils are a problem for agriculture and engineering because they are susceptible to change in volume due to seasonal variation in water content and temperature. One of its morphological properties is slickensides, which result from the ability to contract and crack when dry and expand by wetting. The objective of this study was to evaluate the processes of expansion and formation and propagation of cracks due to the change in water content over time. The expansion process

The environmental problems caused by sewage sludge generated by the growth of the global population and urbanization are drawing the attention of the scientific community worldwide to the need of developing sustainable solutions to use that material. This work investigated the possibilities of using sewage sludge, generated in wastewater treatment plants, as a strategy to improve and stabilize collapsible soils. Different soil–sludge mixtures, with 5%, 10%, and 15% of sludge, were analyzed. For the characterization and analysis of the soil–sludge interaction, physical, chemical, and edometric experiments were performed. The results showed that the addition of sludge to the soil causes a void index reduction, improves particle packaging, and reduces soil collapsibility to the same specific dry apparent weights, i.e., showed to be a promising method for the improvement of collapsible soils.