Document Detail

Free chlorine demand and cell survival of microbial suspensions.
MedLine Citation:
PMID:  17624396     Owner:  NLM     Status:  MEDLINE    
The utility of chlorine residual and chlorine demand as a surrogate for microbial contamination in the water distribution system was evaluated. The chlorine demanded by and cell survival of pure culture suspensions of Escherichia coli, Staphylococcus epidermidis, and Mycobacterium aurum were quantified in solutions with initial free chlorine concentrations of 0.20, 0.40, and 0.80 mg/L. The chlorine demand increased with initial concentration of cells and free chlorine for all species. At equivalent initial cell concentrations, chlorine demand was greatest for M. aurum, followed by S. epidermidis and E. coli. The chlorine contact time required for a 3-log inactivation of E. coli, S. epidermidis, and M. aurum was calculated as 0.032+/-0.009, 0.221+/-0.080, and 42.9+/-2.71 mg min/L, respectively. The ultimate chlorine demand and cell survival were directly proportional. No chlorine demand was observed at cell concentrations less than 10(5)CFU/mL for E. coli or 10(4)CFU/mL for S. epidermidis. M. aurum demanded chlorine at all initial cell concentrations including 10(3)CFU/mL, which was the detection limit of the cell quantification assay. Chlorine demand was determined to be a suitable surrogate indicator of the organisms studied and its utility may be enhanced in locations of the water distribution system that maintain a higher free chlorine residual.
Damian E Helbling; Jeanne M Vanbriesen
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2007-06-12
Journal Detail:
Title:  Water research     Volume:  41     ISSN:  0043-1354     ISO Abbreviation:  Water Res.     Publication Date:  2007 Nov 
Date Detail:
Created Date:  2007-10-26     Completed Date:  2008-01-29     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0105072     Medline TA:  Water Res     Country:  England    
Other Details:
Languages:  eng     Pagination:  4424-34     Citation Subset:  IM    
Department of Civil and Environmental Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA.
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MeSH Terms
Chlorine / chemistry*
Disinfectants / chemistry*
Escherichia coli / physiology*
Mycobacterium / physiology*
Staphylococcus epidermidis / physiology*
Water Microbiology*
Reg. No./Substance:
0/Disinfectants; 7782-50-5/Chlorine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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