This research examined removals of Giardia and Cryptosporidium by clarification
(either dissolved-air flotation [DAF] or lamella [plate] sedimentation) and by
dual-media filtration following clarification. Studies were conducted for
challenge conditions of cysts and oocysts (i.e., high influent concentrations)
and for process design detention times and hydraulic loadings. To evaluate the
effect of water temperature on performance, sets of experiments were performed
for winter and spring seasons. DAF clarification performed better than lamella
sedimentation and consistently resulted in lower turbidity levels and particle
counts. Overall log removals of Giardia and Cryptosporidium by clarification and
filtration were about the same for DAF versus lamella sedimentation. Although
DAF is not recognized under the Surface Water Treatment Rule or the Interim
Enhanced Surface Water Treatment Rule, the authors argue that based on these
findings, DAF plants should receive Giardia and Cryptosporidium removal credits
at least equal to those received by sedimentation plants. Includes 18 references, tables, figures.
| Edition : | Vol. 92 - No. 12 |
| File Size : | 1
file
, 290 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 15 |
| Published : | 12/01/2000 |
