Index to evaluate closed landfills based on leachate parameters

Abstract

After the end of their useful life, waste landfills and their surroundings should continue to be monitored constantly. The main concern is the pollution of groundwater and surface water by leachate, which represents a serious risk to public health. In this work an index is proposed to assess the conditions of a landfill after closure. Insufficient data on the waste entering these areas causes uncertainty as to how long the material will continue to degrade. The presence of polluting elements in landfill leachate was evaluated by characterizing the effluent over a period of ten years. The leachate data were analyzed statistically to test the significance of Pearson’s linear correlation coefficient. Multivariate statistical analysis was used to describe the similarity between the samples considering the total set of variables and their correlations. These results showed the importance given to certain parameters that are not relevant for Brazilian landfills, in which the presence of organic matter is high. The present work contributes by generating information for a better understanding of the impacts caused by landfills in Brazil and in most countries of the Third World, in which organic waste represents at least 50% of the waste discarded in landfills. Through the proposed Deactivated Landfill Assessment Index (DLAI), involving four-parameter analysis (pH, BOD, COD and ammoniacal nitrogen), possible pollution threats can be detected, allowing prioritizing areas for remediation and better allocation of resources.