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Removing Giardia Cysts and Other Particles From Low Turbidity Waters Using Dual‐Stage Filtration
Author(s) -
Horn James B.,
Hendricks David W.,
Scanlan John M.,
Rozelle Lee T.,
Trnka Walter C.
Publication year - 1988
Publication title -
journal ‐ american water works association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.466
H-Index - 74
eISSN - 1551-8833
pISSN - 0003-150X
DOI - 10.1002/j.1551-8833.1988.tb02995.x
Subject(s) - turbidity , filtration (mathematics) , giardia , environmental science , stage (stratigraphy) , environmental engineering , chemistry , zoology , environmental chemistry , pulp and paper industry , biology , microbiology and biotechnology , mathematics , ecology , paleontology , statistics , engineering
Dual‐stage filtration (DSF) in packaged form is a good alternative to conventional rapid‐rate filtration for small utilities. The purpose of the study described in this article was to test the effectiveness of DSF for removing Giardia cysts from low turbidity (<;1 ntu), low temperature (near 32°F [0°C]) water. Removals of total coliform bacteria and turbidity were also determined. Two different water sources were tested, with runs up to 35 h in length. Dual‐stage filtration removed >;99 percent of Giardia cysts from waters with a turbidity of <;1 ntu and a temperature of <;46°F (<;8°C), when proper chemical treatment was applied and the system was operated at 10 gpm/sq ft (6.8 mm/s) or less. Removal of total coliform bacteria exceeded 98 percent, and removal of turbidity exceeded 90 percent.