Solubility of ion and trace metals from stabilized sewage sludge by fly ash andalkaline mine tailing
ZHANG Hongling , SUN Lina , SUN Tieheng
DOI:
Received August 30, 2007,Revised November 26, 2007, Accepted , Available online
Volume 20,2008,Pages 710-716
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Stabilized sewage sludge (SS) by fly ash (FA) and alkaline mine tailing as artificial soil, to be applied on the ecological rehabilitation
at mining junkyards, o ers a potentially viable utilization of the industrial by-product, as well as solves the shortage of soil resource
in the mine area. An incubation experiment with di erent ratios of SS and FA was conducted to evaluate the solubility of ions and
trace elements from stabilized sewage sludge. Results showed that fly ash o set a decrease in pH value of sewage sludge. The pH
of (C) treatment (FA:SS = 1:1) was stable and tended to neutrality. The SO4
2?? and Cl?? concentrations of the solution in the mixture
were significantly decreased in the stabilized sewage sludge by alkaline fly ash and mine tailing, compared to the single SS treatment.
Stabilized sewage sludge by FA weakened the nitrification of total nitrogen from SS when the proportion of FA in the mixture was more
than 50%. The Cr, Ni, and Cu concentrations in the solution were gradually decreased and achieved a stable level after 22 days, for all
treatments over the duration of the incubation. Moreover stabilized sewage sludge by fly ash and/or mine tailing notably decreased the
trace metal solubility. The final Cr, Cu, and Ni concentrations in the solution for all mixtures of treatments were lower than 2.5, 15, and
50 μg/L, respectively.
