Temporal behavior analysis of leachate contamination in a tropical landfill.

Leachate generation is one of the problems present in the landfills and dumps, needing monitoring and quantification for the environmental conservation. The objective of this paper is to evaluate temporal data of leachate contamination in a municipal solid waste (MSW) landfill, located in the midwest of São Paulo state, Brazil. The physical-chemical parameters and chemical compounds of the local groundwater were evaluated during 13 years (2002 to 2015). The methodology included data processing and temporal behavior analysis by Mann-Kendall test. Physical-chemical parameters demonstrated a change from acid to basic medium and decrease of BOD, COD, and TOC concentrations. Chemical compounds demonstrated high concentrations close to the administration building of the landfill, despite the decrease of certain compounds (Al, Fe, Hg, K, Na, Pb, SO42-, total PO43-, Zn) over time in the entire landfill area. The results demonstrate that the landfill is in natural attenuation process, and the structures of the surrounding landscape and the location of the MSW disposal are fundamental to understand the presence and rate of each chemical compound.

Proposal for MSW contaminant classification applied to a tropical aquifer.

Groundwater is a natural resource exploited worldwide causing danger due to the lixiviation of waste deposited, which presents high potential degradation. Internationally, regulation aims for the maintenance of the quality of this resource. But the local lithology, mainly in countries with tropical weather, was not considered. This paper has an objective to propose two methodologies of contaminant identification of municipal solid waste (MSW) considering the Brazilian regulation, the local lithology and the temporal aspect. The study site is located in the midwest of São Paulo, at the Marília Formation, Bauru Aquifer, which presents sandstone rich in calcite. At first, the historic monitoring data accumulated between 2002 and 2015 were statistically organized. Then, methodologies of classification of major constituents and contamination method were developed. After these analyses, the compounds that possibly cause anomaly in the local environment are Al, As, Ba, Ca, Cd, Co, Cr, Cu, phosphatic, nitrogenous, and sulfated compounds, Fe, K, Mn, Ni, and Pb. Some of these have lithogenic genesis typical of tropical environment, and others come from the disposed waste. Despite different approaches, both methods demonstrate efficiency in identifying the pollutants presenting distinctions among themselves in conjunction with actual local regulation and the lithogenic source of certain compounds.

Interaction between municipal solid waste leachate and Bauru aquifer system: a study case in Brazil.

Leachate contamination is a chronic and urgent problem present in municipal solid waste (MSW) landfill. Geochemical mathematical models in this work was suitable to study the dynamics of the leachate from an MSW landfill located in the Midwest of Sao Paulo, Brazil, a region with high precipitation and temperature and rich in chalcophile compounds and lithophile compounds, despite contamination with nitrogenous compounds. After 13 years of local aquifer monitoring, some groundwater samplings in Feb. 2004, Aug. 2007, Nov. 2009, and Feb. 2014 were chosen to be simulated. The hydrolysis is the main process at the landfill, together with absorption, adsorption, complexation, dilution, cation exchange, and oxidation, besides nitrification, reoxidation, and reduction.