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Removal of Cr from tannery sludge by indigenous sulfur-oxidizing bacteria.

Authors :
Fang, D.
Jin, C. J.
Zhou, L. X.
Source :
Journal of Environmental Science & Health. Part A. Toxic/Hazardous Substances & Environmental Engineering. Nov2007, Vol. 42 Issue 13, p2065-2069. 5p. 1 Chart, 4 Graphs.
Publication Year :
2007

Abstract

The aim of the present study was to examine Cr removal from tannery sludge by bioleaching method using indigenous sulfur-oxidizing bacteria with special emphasis on the influence of bioleaching process on sludge settleability. Chemical leaching with sulfuric acid was designed as the control. The results showed that the inoculation of sulfur-oxidizing bacteria and the addition of elemental sulfur were effective in removing Cr from tannery sludge. After 144 hours of bioleaching, 98% of Cr could be leached. Although it took only 8 hours to reduce the sludge pH from 7.8 to about 2.0 by chemical leaching as compared to 144 hours for bioleaching treatment, chemical leaching removed only 91% of the total Cr. Regardless of bioleaching and chemical leaching treatments, sludge settleability improved considerably with a decrease in sludge pH. Bioleaching treatment performed better than chemical leaching in terms of the percentage of settled sludge and the effluent suspended solids (ESS) content in sludge supernatant. Nevertheless, further work should be carried out to investigate the precise mechanisms leading to such enhanced sludge settleability during sludge bioleaching process. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
10934529
Volume :
42
Issue :
13
Database :
Academic Search Index
Journal :
Journal of Environmental Science & Health. Part A. Toxic/Hazardous Substances & Environmental Engineering
Publication Type :
Academic Journal
Accession number :
27406412
Full Text :
https://doi.org/10.1080/10934520701631670