Document Detail


Optimization and/or acclimatization of activated sludge process under heavy metals stress.
MedLine Citation:
PMID:  23212207     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
The present study aimed to overcome the toxicity of the heavy metals load, discharged with the industrial effluents into Alexandria sewerage network, on the activated sludge treatment system through effective acclimation for organic matter and heavy metals removal. Optimization and/or acclimatization of the activated sludge process in the presence of Cu, Cd, Co and Cr contaminating mixed domestic-industrial wastewater was investigated. Acclimatization process was performed through abrupt and stepwise addition of tested metals using sequencing batch reactors treatment approach and evaluated as microbial oxygen uptake rate (OUR), dehydrogenase activity (DHA), organic matter (COD) and heavy metals removal. Abrupt addition of metals adversely affected sludge bioactivity leading to decline in the removal efficiency of the targeted contaminants and loss of floc structure. Metals IC(50) confirmed that copper possessed the highest toxicity towards the OUR, DHA activity and COD removal with orders Cu > Cd > Cr > Co; Cu > Cd > Co = Cr and Cu > Cd > Cr > Co, respectively. The highest metal removal was recorded for Cd followed by Co, Cu and finally Cr, most of which was retained in the dissolved influent. However, controlled stepwise application of the tested metals exhibited high sensitivity of DHA and OUR activities only at the highest metal concentrations although enhanced at the lowest concentrations while COD removal was not significantly affected. In conclusion, this approach resulted in adaptation of the system where sludge microbes acquired and developed natural resistance to such metals leading to remarkable enhancement of both organic matter and heavy metals removal.
Authors:
Ebtesam El Bestawy; Shacker Helmy; Hany Hussein; Mohamed Fahmy
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-12-5
Journal Detail:
Title:  World journal of microbiology & biotechnology     Volume:  -     ISSN:  1573-0972     ISO Abbreviation:  World J. Microbiol. Biotechnol.     Publication Date:  2012 Dec 
Date Detail:
Created Date:  2012-12-5     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9012472     Medline TA:  World J Microbiol Biotechnol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
Department of Environmental Studies, Institute of Graduate Studies and Research, Alexandria University, 163 Horria Ave. El-Shatby, P.O. Box 832, Alexandria, Egypt, ebtesamelbestawy@yahoo.com.
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