Avaliação dos efeitos da infiltração de concentrado de osmose inversa em um aterro sanitário

Abstract

The increasing generation of municipal solid waste (MSW) and its management is one of the major environmental challenges faced by society today. In this context, landfills represent the main solution for the final disposal of MSW in Brazil and worldwide, although the leachate generation is an inherent byproduct of this practice and requires appropriate treatment. Reverse osmosis (RO) stands out as one of the most efficient technologies in this context, but it generates a residual stream known as reverse osmosis concentrate (ROC), the disposal of which remains a challenge. Among the alternatives for managing ROC, infiltration into the landfill body is the most widely adopted practice. The aim of this study was to evaluate the effects of ROC infiltration in a large landfill located in northeastern Brazil, consisting of two units: a decommissioned (Landfill A), currently in the post-closure care phase, and an operational (Landfill B). The RO system is installed at Landfill B, and its ROC is directed for infiltration into Landfill A. Data from four years of monitoring of rainfall, leachate production, infiltrated volume, and the physicochemical characterization of the leachate from Landfill B and its ROC were analyzed. In addition, six sampling campaigns were conducted over one year for the physicochemical characterization of the leachate from Landfill A and the ROC from Landfill B. The results indicated that ROC infiltration did not significantly influence leachate production at Landfill A, which was more strongly affected by rainfall. The one-year monitoring of leachate from Landfill A and ROC showed a strong correlation between chloride values in the leachate and the following parameters in the ROC: chloride, conductivity, DOC and TAN. ROC conductivity also showed a strong correlation with COD, DOC and TAN in the leachate. However, the results of the Mann-Kendall test did not indicate any upward trend in these parameters in the leachate from Landfill A. Thus, it is concluded that, under the studied conditions, the infiltration of ROC into a decommissioned landfill did not contribute to an increase in leachate production. Furthermore, although a strong correlation was observed between certain leachate parameters and the ROC, no increasing trends in these parameters were identified in the leachate generated at Landfill A.