Disposição de resíduos sólidos numa voçoroca e seus impactos sobre as águas: um estudo de caso em Uberlândia/MG

Abstract

Between 1989 and 1993 the City Hall of Uberlândia disposed all of the solid wastes generated by the municipal district, into two large ravines with advanced levels of erosion. These two ravines are located within the municipality s own agricultural zone, specifically, in an area known as Douradinho Farm. On the same year that the City Hall came to a decision to halt the dumping of solid wastes into these ravines, they also determined that these two specific locations would become a landfill. However, ever since these ravines were transformed into a landfill, no one has ever researched how the landfill is affecting the neighbouring environment. Taking this statement into consideration, the broad objective of this case study is to evaluate the landfill s consequences on the quality of the adjacent superficial and subterranean water supply. In order to achieve this objective, an extensive bibliographical review was undertaken, comprising of technical reports, cartographical materials, as well as information from other bibliographical sources pertaining to this subject matter. Furthermore, a meticulous field study enabled the carrying out of onsite geological tests, the construction of wells to monitor ground water, and the gathering of soil and water (superficial and subterranean) samples. The soil samples were collected from two sites: an onsite slope created naturally by erosion and at the top layer of the landfill. These soil samples were examined at the Geotechnical Laboratory of the College of Civil Engineering of the Federal University of Uberlândia (UFU), with the objective of ascertaining their geotechnical characteristics. Conversely, the superficial and subterranean water samples were analysed at the Chemical Analysis Laboratory of the Chemistry Department of UFU, in order to determine whether the water is contaminated or not. The test results obtained from the Geotechnical Lab clearly point out that the soil used to cover the landfill, has a high permeability, condition which allows precipitation to infiltrate and consequently produce the seepage of leachate. Therefore, it is not startling that the test results of the water samples indicate that, both the superficial water and the groundwater are contaminated. Nonetheless, the case study recommends a rehabilitation project, based on well-established landfill rehabilitation procedures, which, if executed correctly, could recover the area surrounding the landfill.