Biodegradação dos resíduos sólidos urbanos por meio das características do lixiviado gerado no aterro sanitário em Campina Grande-PB.

Abstract

Physicochemical and biological reactions occur inside the landfill massif, which generates by-products such as leached liquids. To monitor these liquids by conducting physical and chemical tests, allows analyzing the landfill behavior, considering that this effluent reflects the variations that take place in the residues massif. Based on the understanding of indicators in leachate it is possible to evaluate the process of waste biodegradation over time. Therefore, the objective of this work was to study the biodegradation of urban solid waste deposited in a landfill in the Brazilian semiarid, taking into account the leachate generated in different Cells. The research consisted of a collection of leachate samples, in natura, from three Cells (Cell 3, Cell 4 and Cell 1+3). The collection was carried out in manholes that receive the leachate generated by the Cells under study. After the collections, the leachate was characterized by physical-chemical tests (potential of hydrogen (pH), Volatile Fatty Acids (VFAs), Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD) and heavy metals); and toxicity (phytotoxicity). Besides, Principal Component Analysis (PCA) was applied to the data obtained over the study period. The results show that the advancement of the biodegradation phases of the grounded waste, evidencing a transition between the acidic and methanogenic phases. It is noteworthy that when pH values were acidic, high concentrations of VFAs, COD and heavy metals were obtained, as the biodegradation process evolved, the pH values increased and the indicators mentioned above decreased, indicating that the easily biodegradable residues were transformed and metabolized. The leachate showed a higher phytotoxic effect on tomato seeds tomato (Solanum lycopersicum) and cabbage (Brassica oleraceae) in the acid phase, when the degradative process evolved, with the consequent transition between phases, there was a reduction in the toxic load of the leachate. From the analysis of the physicochemical indicators, it was noted that the leachate had similar behavior in the studied cells, but due to the age difference between them, there is an indication that they are in different stages of the waste degradation. Overall, such analysis can contribute to the understanding of the degradation of municipal solid waste.