Influence of physical-chemical parameters on the composition of toxic constituents in landfill leachate

摘要

The characterization of leachate generated in landfills can clarify the degradation phenomena that occur inside the waste cells and indirectly indicate their toxic potential. The objective of this study was to evaluate the influence of physical and chemical parameters on toxic components, such as metals and total ammonia nitrogen (TAN), found in the leachate generated by a cell from the Sanitary Landfill in Campina Grande, Para?-ba. pH, volatile fatty acids (VFA), total alkalinity (AT), chlorides, chemical oxygen demand (COD), TAN and metals (Pb, Cr, Co, Ni, Fe and Mn) were investigated. The results showed that during the acid fermentation phase a high production of VFA occurred in the landfilled waste mass, which maintained the values of pH below neutrality and contributed for high concentrations of COD, chlorides and a higher toxicity in the leachate compared with the analyzed metals. However, in the case of methanogenic conditions, a decrease in the VFA contents was observed and, with this, the pH tended to be basicity, making the medium more alkaline, favoring the precipitation of the studied metals, but contributing to the high levels of TAN. It is possible to conclude that pH and VFA had a strong influence on the metals (Pb, Cr, Co, Ni, Fe and Mn) and TAN during the 150 days of evaluation.