Many authors have documented the positive effects of flushing on water quality. Oberoi
(1994), in a study on the Edmonton water network, found that chlorine
residuals and turbidity levels were improved by flushing and the benefits remained for up
to two years. Two other authors (Kuehn et al., 2001; Cossins et al., 1999) found lower
turbidity levels in the network following UDF. Coliform positive episodes were also
found to be reduced after UDF in Fort Belvoir, according to Antoun et al. (1997).
Another study conducted by the same authors in Virginia and North Carolina came to the
same conclusions (Antoun et al., 1999).
Although the benefits of UDF have been often described, there has not been extensive
analysis of the potential adverse short term effects of flushing, due to the incomplete
removal of loose deposits at the end of the procedure. The objective of this study was
to identify the short term (1 day to 1 week) effects of flushing on water quality.
To address this issue, three unidirectional flushing campaigns were performed in
Jonquiere (Quebec, Canada) from May 2001 to May 2002. UDF conditions were
characterized by velocities of 1 to 2 m/s and a closure criterion of 5 NTU turbidity.
Water quality samples were collected before, shortly after (24 hours) and one week after
flushing and analyzed for parameters that included: turbidity, chlorine residual, total iron, total coliforms, total viable counts,
total direct counts and heterotrophic plate counts. Seven sampling locations in total were
selected for this analysis: two at the plants (as a control for influent); and five in the
selected sites. A total of 20 analyses were performed for each parameter. Water quality
data from the flushing sites were compared to samples from the plants in order to
disregard variations attributable to distributed water quality. Includes 7 references, tables, figure.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 300 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 7 |
| Published : | 11/02/2003 |
