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Giardia and Cryptosporidium removals by clarification and filtration under challenge conditions

TitleGiardia and Cryptosporidium removals by clarification and filtration under challenge conditions
Publication TypeJournal Article
Year of Publication2000
AuthorsEdzwald JK, Tobiason JE, Parento LM, Kelley MB, Kaminski GS, Dunn HJ
JournalJournal - American Water Works Association
Volume92
Issue12
Start Page70
Pagination70-84
Date Published12/2000
Other NumbersProduct Number: JAW_0053070
Abstract

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.