Characterization of dissolved organic matter in leachate discharged from final disposal sites which contained municipal solid waste incineration residues.

Abstract

The properties of dissolved organic matter (DOM) in the leachates discharged from lysimeters and landfill sites containing municipal solid waste incineration residues (MSWIRs) were studied. DOM samples were divided into hydrophobic acid, base, neutral (Hpo-A, Hpo-B, Hpo-N) and hydrophilic (Hpi) fractions using the fractionation method employing DAX-8 resin. Hpi was the smallest fraction of all the raw leachate samples. The proportion of Hpo-N increased with increasing operating time. Landfill sites containing abundant non-combustible wastes showed a higher proportion of Hpo-B than Hpo-A. The molecular weights and functional groups of the DOM fractions were studied by using gel permeation chromatography and FTIR, respectively. In addition, the fluorescent properties and binding sites of the DOM fractions were investigated using fluorescence analysis. In the synchronous scan spectra of each DOM fraction, most of DOM fractions showed an emission peak for the main fluorophores at around 300 nm or 350 nm, which are regarded as aromatic amino acid-like fluorophores. The interaction between the DOM fraction and the pollutants (Cu(2+), pyrene and phenanthrene) was investigated using the fluorescence quenching method. It was observed that the aromatic amino acid-like fluorophores in the DOM fractions could be an important factor affecting complexation with the pollutants.