Bioremediation Process for Sediments Contaminated by Heavy Metals:  Feasibility Study on a Pilot Scale

The core stages of a sediment remediation processthe conditioning of dredged sludge by plants and the solid-bed leaching of heavy metals using microbially produced sulfuric acidwere tested on a pilot scale using a highly polluted river sediment. Conditioning was performed in 50 m3 basins at sludge...

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Veröffentlicht in:Environmental science & technology 2004-03, Vol.38 (5), p.1582-1588
Hauptverfasser: Seidel, H, Löser, C, Zehnsdorf, A, Hoffmann, P, Schmerold, R
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Sprache:eng
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Zusammenfassung:The core stages of a sediment remediation processthe conditioning of dredged sludge by plants and the solid-bed leaching of heavy metals using microbially produced sulfuric acidwere tested on a pilot scale using a highly polluted river sediment. Conditioning was performed in 50 m3 basins at sludge depths of 1.8 m. During one vegetation period the anoxic sludge turned into a soil-like oxic material and became very permeable to water. Reed canary grass (Phalaris arundinacea) was found to be best suited for conditioning. Bioleaching was carried out in an aerated solid-bed reactor of 2000 L working volume using oxic soil-like sediment supplemented with 2% sulfur. When applying conditioned sediment, the oxidation of easily degradable organic matter by heterotrophic microbes increased the temperature up to 50°C in the early leaching phase, which in turn temporarily inhibited the sulfur-oxidizing bacteria. Nevertheless, most of the metal contaminants were leached within 21 days. Zn, Cd, Mn, Co, and Ni were removed by 61−81%, Cu was reduced by 21%, while Cr and Pb were nearly immobile. A cost-effectiveness assessment of the remediation process indicates it to be a suitable treatment for restoring polluted sediments for beneficial use.
ISSN:0013-936X
1520-5851
DOI:10.1021/es030075d