Degradação de resíduos e alterações na resistividade elétrica, pH e Eh

Abstract

DC resistivity combined with pH and Eh measured in soil samples, were used for evaluation of the geochemical behavior of buried solid waste, during the degradation process of organic matter. The studied area is a controlled landfill, characterized by the disposition of domestics waste in ditches, of which closed ditches were selected among 12/2001 to 12/2007. The presence of values below 30Ω.m in the lines obtained on the ditches and the absence of this value range in the reference line, suggest the leachate presence. The time correlation between pH and Eh can indicate the geochemical predominant conditions, which govern the solubility or precipitation of ions, consequently, the electric resistivity pattern. The pattern described for the closed ditches between 2005 and 2007 can indicate growing leachate production. The obtained data for the 2004 ditch suggest initial processes of geochemical instability, with relative increase of the electric resistivity probably associated to the ions precipitation, whose evolution results in the pattern described for the 2003 ditch. The retaking of the decomposition process of organic residues is evidenced by high and low resistivity value and pH and Eh increase, for the 2001 and 2002 ditches. © 2009 Sociedade Brasileira de Geofísica.