In this study, the relevance of the presence of
Escherichia coli
in drinking water as an indicator of
point-of-use chlorination efficiency is examined. The survival of clinical isolates of human enteric pathogenic bacteria
(
Klebsiella pneumoniae
,
Pseudomonas aeruginosa
,
Salmonella typhi
,
Shigella dysenteriae
,
Staphylococcus aureus
,
Streptococcus faecalis
and
Vibrio cholerae
) as well as
E. coli was monitored as a function of effective germicidal
concentration and contact time. The inactivation kinetics indicated that the minimum effective dose for three-log units
(99.9%) inactivation of
E. coli (C·
T99.9% = 10 mgl
-1-min) can sufficiently eliminate the other pathogens (C·
T99.9% ranged
from 5.6–10.5 mgl
-1-min); the exception being
K. pneumoniae, which required more than 1.4-times higher dose. In
general, the results implied that the branded hypochlorite solution should effectively inactivate almost all vegetative
bacteria in household drinking water at the manufacturer’s recommended dosage of 0.5 mgl
-1 after at least 30 minutes
contact time. The application of point-of-use chemical disinfectants to drinking water in households will significantly
reduce the incidence of water-borne infections particularly in rural communities where central treatment of water is
mostly unavailable.
