Alexandre Lisboa Lago

Aplicação integrada de métodos geofísicos em uma área de disposição de resíduos sólidos urbanos em Bauru-SP

Geophysics has shown effectiveness in identify areas contaminated by urban solid wastes, contributing to become more effective sounding programs directed to collect of samples and installation of monitoring systems. In this context, this work had as purpose evaluating the potentialities of the integration of geophysical methods (resistivity, induced polarization and self-potential) in the environmental characterization of the area of the sanitary landfill of the city of Bauru-SP. The self-potential method allowed to detect the direction of the underground flow. The resistivity and induced polarization methods allowed to identify anomalies inside of the saturated zone, that characterize the presence of contamination generated for the migration of the percolated proceeding of the disposal of solid waste. This contamination is confirmed by direct investigation (chemical analysis of the water collected in the monitoring wells). The geophysical methods used had supplied a great number of information about the several characteristics related to interaction between waste disposal area and environment.

GPR utilizado na deteção da geometria de cavas usadas para disposição de resíduos de óleos lubrificantes

A variety of environmental problems occurs due to the inadequate disposition of residues. Applied geophysics methodologies to environmental studies show great results in the investigation of contaminating. GPR is a practical and fast geophysical method in such investigations, because the electromagnetic signal assists in the delimitation of the contaminating, addressing direct techniques of investigation (boreholes and wells). This study was developed in an old disposition area to residues lubricants oils (dense nonaqueous phase liquids - DNAPL) in the municipal district of Ribeirao Preto, Sao Paulo State. This area is situated in the geological domains of the basaltic floods of the Serra Geral Formation and sandstones of the Botucatu Formation. GPR acquisition was carried out inside and next to 4 ditches of residues disposition, with 100 MHz unshielded antennas, enabling a maximum investigation depth of 7 meters. The limits and of the ditches base can be identify in the GPR sections, except in the ditch 1, which the base is not delineated by GPR. The results show that GPR signal is much attenuated below ditches. This fact could be result of a bacteriological activity in the residue or increase of dissolved salts in the soil caused by acid pH of the residue.