Avaliação das propriedades ambientais do lixiviado de obras geotécnicas melhoradas com coprodutos siderúrgicos

Abstract

In the construction of geotechnical works, the local soil often does not have sufficient characteristics to be used for this purpose, making it necessary to improve its mechanical and chemical characteristics. One of the possibilities is to add other materials to interact with the soil. Linked to this need for civil construction, there is an opportunity to use co-products generated by the steel industry. These have proven characteristics for soil improvement. Once these materials can be used, they add value to them and reduce the environmental impacts generated by their final destination and soil extraction in their deposit. However, questions about the soil-co-product interaction and leaching products of these mixtures are still recurrent by several environmental agencies.Thus, the objective of this work was to evaluate the effects of incorporating steel byproducts into the soil in environmental control parameters. Soil-co-product mixtures were investigated in the proportions of 30% for KR (Kanbara Reactor), steel slag (LD), air-cooled blast furnace slag (ACBFS or EFRA), granulated blast furnace slag (EGAF) and 6% for Flue Gas Desulfurization (FGD), in terms of dry mass. In order to be able to compare with other stabilizing agents typically employed as soil improvers, soils were mixed with Portland cement. The possible changes in the properties of the soil and the percolating effluent were verified through the percolation column test. The risk of co-products to the environment was also assessed through toxicological and ecotoxicological assessments.The results showed that the incorporation of steel residues into the soil modifies the efluente and soil properties, but in almost all these parameters still remain in accordance with the recommendations used as a reference, CONAMA 420, 430 and Potability Standard of Resolution No. 5.Thus, it was found that the use of co-products in soil mixtures, in the proportions studied, does not pose a risk to the environment and human health, except for the sample effluent containing a mixture with LD, in which the nitrite parameter was above the allowed to be considered drinkable to human beings