In:
Applied and Environmental Microbiology, American Society for Microbiology, Vol. 64, No. 4 ( 1998-04), p. 1237-1241
Abstract:
Semicontinuous biohydrometallurgical processing of fly ash from municipal waste incineration was performed in a laboratory-scale leaching plant (LSLP) by using a mixed culture of Thiobacillus thiooxidans and Thiobacillus ferrooxidans . The LSLP consisted of three serially connected reaction vessels, reservoirs for a fly ash suspension and a bacterial stock culture, and a vacuum filter unit. The LSLP was operated with an ash concentration of 50 g liter −1 , and the mean residence time was 6 days (2 days in each reaction vessel). The leaching efficiencies (expressed as percentages of the amounts applied) obtained for the economically most interesting metal, Zn, were up to 81%, and the leaching efficiencies for Al were up to 52%. Highly toxic Cd was completely solubilized (100%), and the leaching efficiencies for Cu, Ni, and Cr were 89, 64, and 12%, respectively. The role of T. ferrooxidans in metal mobilization was examined in a series of shake flask experiments. The release of copper present in the fly ash as chalcocite (Cu 2 S) or cuprite (Cu 2 O) was dependent on the metabolic activity of T. ferrooxidans , whereas other metals, such as Al, Cd, Cr, Ni, and Zn, were solubilized by biotically formed sulfuric acid. Chemical leaching with 5 N H 2 SO 4 resulted in significantly increased solubilization only for Zn. The LSLP developed in this study is a promising first step toward a pilot plant with a high capacity to detoxify fly ash for reuse for construction purposes and economical recovery of valuable metals.
Type of Medium:
Online Resource
ISSN:
0099-2240
,
1098-5336
DOI:
10.1128/AEM.64.4.1237-1241.1998
Language:
English
Publisher:
American Society for Microbiology
Publication Date:
1998
detail.hit.zdb_id:
223011-2
detail.hit.zdb_id:
1478346-0
SSG:
12
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