The Central Wyoming Regional Water System operates 29 groundwater
collection devices in an alluvial aquifer adjacent to the North Platte River. These
collection devices were previously designated as being "ground water under the direct
influence of surface water" (GWUDISW). In lieu of constructing a conventional surface
water treatment plant the utility opted to perform a two-year study to demonstrate that
riverbank filtration (i.e. natural filtration) provides the 2.0 log reduction of
Cryptosporidium required under the Interim Enhanced Surface Water Treatment Rule
(e.g. riverbank filtration is the primary filtration process). Using multiple surrogates of
various sizes encompassing those of Giardia and Cryptosporidium, the utility
demonstrated 2.0-log reductions in over 90 percent of matched-data pairs. No Giardia or
Cryptosporidium were found in any of the 170 groundwater samples. This level of
removal was achieved during the summer months when infiltration rates are high due to
increased river stage and well-field production. Includes 19 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 620 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 19 |
| Published : | 11/01/2005 |
