Análise da incorporação do lodo de uma Estação de Tratamento de Água (ETA) em solo para utilização em camadas impermeabilizantes de aterro sanitário

Abstract

Water treatment is essential to guarantee the drinking water supply to the population. Raw water undergoes physical operations and chemical processes that are necessary for treated water distribution to cities, which in turn generates residues. These residues generated in water treatment plants (WTP) is called WTP sludge, whose disposal must follow criteria so that it does not cause environmental harm. Sanitation companies face a major challenge in managing the WTP sludge, both in terms of its final disposal and alternatives for its treatment. On the other hand, solid waste disposal directly on the ground is harms to the environment. To minimize this environmental impact, waterproofing barriers are designed in landfills to prevent liquid percolation and consequent underground water resources contamination. Thus, this work evaluated the potential of using WTP sludge in landfills’ base and cover layers. This practice is used in countries such as the USA and the United Kingdom and has the following advantages: reducing the extraction of soil from deposits and environmentally appropriate disposal of this waste. The research involved the characterization of the WTP sludge as well as carrying out compaction tests of two different concentrations of soil-sludge mixtures (2.5% and 5%) with different moisture levels. With the test results, the compaction curve was drawn to choose the best soil and sludge mixture concentration, with which the hydraulic conductivity and consolidation tests were carried out. The results indicated that the addition of sludge maintained (2.5%) or improved (5%) the permeability characteristics for the residual soil under study, meaning that, in the best condition, the permeability was in the order of magnitude of 10-9 m/s, ideal for waterproofing applications, such as mineral barriers in landfills.