Effects of tri-valent (Cr(III)) and hexa-valent (Cr(VI)) chromium on the growth of activated sludge

The effects of Cr(VI) and Cr(III) species on the activated sludge growth rate have been assessed for a batch growth system, for a range of chromium concentration between 0 and 320 mg l −1. Cr(VI) was found to stimulate microbial growth for concentrations up to about 25 mg l −1, exhibiting maximum gr...

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Veröffentlicht in:Journal of hazardous materials 2006-05, Vol.133 (1), p.212-217
Hauptverfasser: Gikas, Petros, Romanos, Pavlos
Format: Artikel
Sprache:eng
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Zusammenfassung:The effects of Cr(VI) and Cr(III) species on the activated sludge growth rate have been assessed for a batch growth system, for a range of chromium concentration between 0 and 320 mg l −1. Cr(VI) was found to stimulate microbial growth for concentrations up to about 25 mg l −1, exhibiting maximum growth stimulation at 10 mg l −1, whilst the lethal dose was found to be between 80 and 160 mg l −1. On the other hand, Cr(III) was also found to stimulate microbial growth for concentrations up to about 15 mg l −1, (with a maximum stimulation concentration at 10 mg l −1), whilst the lethal dose was found to lie between 160 and 320 mg l −1. The results indicate that Cr(VI) is more toxic to biomass at relatively high concentrations (higher than 70 mg l −1) whilst it has a more pronounced growth stimulation effect at relatively smaller concentrations (less than 25 mg l −1), compared with Cr(III).
ISSN:0304-3894
1873-3336
DOI:10.1016/j.jhazmat.2005.10.023