Aplicação da eletrorresistividade para detecção de zonas de acúmulo de biogás em aterro sanitário

Abstract

Energy production from biogas generated in sanitary landfills is an economically viable and sustainable alternative, contributing to the global energy transition. Biogas is a gaseous mixture primarily composed of methane (CH₄) and carbon dioxide (CO₂) resulting from the anaerobic degradation of organic matter in solid waste. Brazil has significant potential for energy generation through biogas, as approximately 45.3% of the country's urban solid waste is composed of organic matter. This study presents the results of a geophysical investigation conducted at the Metropolitan West Sanitary Landfill of Caucaia (ASMOC), aiming to characterize the existing geoelectrical layers and identify potential biogas accumulation zones. Eight geophysical acquisition sections were performed using the electrical resistivity method and a dipole-dipole array. Aerial images were also obtained for aerophotogrammetry of the ASMOC, and flow rates from biogas collection wells in the landfill were analyzed. The geophysical inversion sections revealed a predominantly conductive character throughout the landfill, with resistivities ranging from 1.2 to 127 ohm·m. The background resistivity values found in the sections varied between 1.2 and 5 ohm·m, indicating an extremely conductive nature within the ASMOC, which is associated with the presence of organic matter, leachate, and rainwater percolation. The study identified a zone with higher resistivity values (associated with biogas) located in the shallower and central region of the landfill (up to 15 meters deep). Flow rate data showed that the most productive biogas wells are located in the central region of the ASMOC, corroborating the geophysical findings.