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Use of coliphages to evaluate water treatment processes and determine faecal contamination origin of source waters
Okeyo, A.; Coetzee, M. & Momba, M. N. B.
Abstract
Viral indicators were used to evaluate the
effectiveness of water treatment processes and to determine
the source of faecal pollution with a view to promote water
source management. Water samples were collected from
three critical points of the Temba, Klipdrift and Wall-
mansthal water treatment plants (raw water, settled water
and filtered water). The viral indicator concentrations and
selected physicochemical parameters were measured using
standard methods. Random water samples were subjected
to real-time polymerase chain reaction analyses. Sub-
sequent to filtration, the removal efficiency of the three
Waterworks was recorded as follows: 93.2, 96.1 and
95.7 % for somatic coliphages, respectively; and 69.4 and
68.4 % FRNA coliphages for Temba and Klipdrift. There
was a notable 50 % reappearance of FRNA coliphages in
filtered water samples from Wallmansthal. Positive corre-
lations were observed between the physicochemical
parameters and somatic coliphages, with the exception of
the pH and the temperature in Wallmansthal. Both turbidity
and temperature indicated positive correlations with FRNA
counts from Temba and Klipdrift. Negative correlations
were observed between all the physicochemical parameters
and FRNA counts from Wallmansthal. The real-time
polymerase chain reaction analyses revealed the persis-
tence of GA genotype FRNA (Group II, which is of human
faecal origin) in all the water samples. The MS2 genotype
(Group I) and Q
β
genotype (Group III) FRNA, which are
of animal origin, were detected only in the raw water from
Temba. Efforts should be focused on the protection of water sources and the optimisation of treatment processes
in order to prevent viral persistence during water treatment.
Keywords
Viral indicators; Treatment efficiency; Faecal pollution; Water source
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