Riverbank filtration (RBF) has been recommended
as a treatment process to remove Cryptosporidium
parvum in surface waters. A comprehensive study
was undertaken in southwestern Ohio to investigate
several aspects of RBF, specifically the effects of infiltration,
streambed scour, and high river-stage frequencies
on RBF efficiency and potential breakthrough of
pathogens.
During periods of high river stage and flow, scour
of the streambed (e.g., removal of the fine-grained
sediments on the bottom of a river) may occur. Scour
has been thought to reduce the filtration capability of
an RBF system, and the US Environmental Protection
Agency has held that scour of the streambed at RBF
sites is problematic. In other words, if the streambed
is removed, the system becomes vulnerable to breakthrough
by Cryptosporidium and other pathogenic
protozoa. This study, undertaken in part to investigate
this concern, found no direct evidence that scour
occurred at any degree of magnitude at this site or
had any adverse effect on water quality. In addition,
this work examined variations in the rate of infiltration
of surface water caused by high river-stage
events and found that the frequency of occurrence for
high-infiltration periods was low. Results indicated
that the streambed and aquifer were able to buffer
water quality effects from major increases in the infiltration
rate.
Until now, these significant issues surrounding RBF
had not been fully investigated and were only partially
understood. This research should help build confidence
in RBF as an important treatment tool that can help
utilities comply with the Surface Water Treatment Rule
and other regulations. Includes 21 references, figures.
| Edition : | Vol. 96 - No. 12 |
| File Size : | 1
file
, 550 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 13 |
| Published : | 12/01/2004 |
