[Chelating stabilization of heavy metals in fly ash from municipal solid waste incinerators for co-disposal in sanitary landfill].

The characteristics and leaching behavior of heavy metals in fly ash, sampled from 4 MSWI plants, were investigated in this study. The results indicated that the main elements of fly ash were Si, Ca, Al, Cl, and heavy metals such as lead, zinc, copper, chromium and cadmium were enriched in fly ash which had great environmental risk. However, co-disposal of fly ash in sanitary landfill was an available and practical resolvent. For disposal security, the leaching procedure of toxicity basing on co-disposal scenario, which had been implemented from 1st May 2007, had increased the acidity of leachant to 0.3 mol x L(-1). The experiments of chelating stabilization technology using dithiocarbamate were carried out for MSWI fly ash treatment. The results indicated that heavy metals in fly ash were fixed by DTC in manner of chelating reaction. With the amount of additive reaching 3% (mass fraction), the concentrations of heavy metals in leachate of these fly ash samples could meet the demand of co-disposal in sanitary landfill.