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Iranian Journal of Environmental Health, Science and Engineering
Iranian Association of Environmental Health (IAEH)
ISSN: 1735-1979
Vol. 5, No. 4, 2008, pp. 225-234
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Bioline Code: se08038
Full paper language: English
Document type: Research Article
Document available free of charge
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Iranian Journal of Environmental Health, Science and Engineering, Vol. 5, No. 4, 2008, pp. 225-234
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Effects Of 4-Chlorophenol Loadings On Acclimation Of Biomass With Optimized Fixed Time Sequencing Batch Reactor
Movahedyan, H.; Assadi, A. & Amin, M. M.
Abstract
Chlorinated phenols in many industrial effluents are usually difficult to be removed by conventional
biological treatment processes. Performance of the aerobic sequencing batch reactor treating 4-
chlorophenol containing wastewater at different loadings rates from 0.0075 to 1.2 g4CP/L.d was
evaluated. The sequencing batch reactor was operated with fill, react, settle and decant phases in the order of 10:370:90:10 min, respectively, for a cycle time of 8 h at 10 days solid retention time and 16 h
hydraulic retention time in the stable period. The effects of 4-chlorophenol loadings on the 4-
chlorophenol and chemical oxygen demand removal percents, yield coefficient (Y), biomass variation and
sludge volume index were investigated. High chemical oxygen demand removal efficiencies (95±3.5%)
and approximately complete 4-chlorophenol removal (>99%) were observed even in the absence of
growth substrate. The degradation of 4-chlorophenol led to formation of 5-chloro-2-hydroxymuconic
semialdehyde, which was more oxidized, indicating complete disappearance of 4-chlorophenol via metacleavage pathway. A compact sludge with excellent settleability (sludge volume index=47±6.1 mL/g)
developed during entire acclimation period. High removal efficiencies with sequencing batch reactor may
be due to enforced short term unsteady state conditions coupled with periodic exposure of the
microorganisms to defined process conditions which facilitate the required metabolic pathways for
treating xenobiotics containing wastewater.
Keywords
Sequencing batch reactor, 4-chlorophenol, biodegradation, organic loading, mixed culture, xenobiotic
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© Copyright 2008 - Tehran University of Medical Sciences Publications Alternative site location: http://diglib.tums.ac.ir/pub/
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