Adição de lodo de esgoto em solo de cobertura de aterros sanitários

Abstract

Sewage treatment plant sludge - SSTP is an unavoidable by-product of biological sewage treatment that contains toxic substances. With the growth of services in this sector, the generation of SSTP has a great potential for increase which, without proper destination, would cause serious environmental damage. On the other hand, in landfills, the great demand for material for coverage is an economic barrier. Therefore, studies that evaluate the conditions for the application of SSTP in these coverings are extremely important. In order to determine the viability of this practice, the geotechnical parameters for the soil + SSTP mixture were studied, and for SSTP, the agronomic characteristics. The study of the mixture for the application in daily, intermediate coverings and for the hydraulic barrier layer of the final cover, was done based on the determination of the parameters of permeability and stability of slopes, in mixtures 0 (control), 5 and 10% of SSTP. The granulometric analysis, liquidity and plasticity limits, compaction, permeability and direct shear were determined. The application of LETE in the erosion control layer of the final cover was evaluated based on data on concentrations of nutrients, chemicals and microbiological analysis. The results showed that the soil + SSTP mixture is suitable for use in coverings and layers when 5% SSTP is used. This mixture complied with the minimum parameters of geotechnical behavior indicated for use in daily, intermediate coverings and hydraulic layer of the final cover (k <5x10-5 cm / s, classification according to SUCS as SC, and IP of 7% to 15%) . Regarding the erosion control layer of the final cover, it was observed that the SSTP has characteristics that allow it to be applied, considering that it is a Class B1 sludge according to CONAMA resolution No. 498. The annual application rate was 15, 82 t ha-1 , estimated based on nitrogen measurements.