Efeitos da adição de lodo de ETA como substituição parcial de solo em tijolo de solo-cimento

Abstract

In Brazil, about 75% of drinking water comes from conventional treatment in water treatment plants (WTPs). In this process, waste ends up being generated, especially the sludge from decanters (WTPS), solid waste that needs an environmentally appropriate destination, since its estimated generation in the country is 4 million tons per year. The present work sought to evaluate the effects of the addition of WTPS as a partial soil substitute in soil-cement bricks, with a 1:9 mix (cement:soil). The residue was collected during the cleaning of the decanters and by means of siphoning at the WTP in the municipality of Toledo - PR. Bricks were made with replacement of 5, 10,15, 25 and 35% of the soil by WTPS, in addition to control samples (0%). The moldings took place in industrial equipment, in order to reproduce as much as possible real manufacturing conditions. The samples were submitted to water absorption and compressive strength tests. By increasing the percentage of sludge, the compressive strength of the material showed a reduction, however, the normative requirements were met until the addition of 15% of WTPS. As for absorption, there was an increase in this parameter while the percentage of sludge was increased, however, similarly to the mechanical strength, the material was able to meet the regulatory requirements until the addition of 25% of WTPS. In view of the above, it is observed that the incorporation of this environmental liability in soil-cement bricks can present itself as a viable alternative to processes that generate more impacts on the environment, such as in natura release into rivers and even disposal in landfills.