Analysis of quantification methodologies for humic substances in leachates from solid waste landfills

Abstract

Humic substances (HS) are defined as amorphous polymers, with high molecular weight and complex and heterogeneous structures that frequently change their configurations depending on the interactions between the functional groups present in their structures. The presence of these substances, particularly in landfill leachates and in greater quantities in leachates from old landfills, hinders the treatment of leachate due to the high degree of recalcitrance of organic matter. In this study, two quantification methods were tested for two leachates generated in solid waste landfills located in Rio de Janeiro State: the Gericinó Controlled Landfill Gericinó (GCL) and the Gramacho Metropolitan Landfill (GML). The study also analyzed the fractionation of humic substances in fractions of Humic acids (HA) and fulvic acids (FA). The results of the quantification of HS were, respectively, 616 and 608 mg L^-1 for the leachate from GCL and 1182 and 1191 mg L^-1 for leachate from GML. The leachate from GCL presented 33% (201 mg L^-1) of HA and 67% (411 mg L^-1) of FA and the leachate from GML presented 37% (437 mg L^-1) of HA and 63% (741 mg L^-1) of FA.

Keywords:
fulvic acids; humic acids; recalcitrant organic matter.