AWWA JAW53070

This research examined removals of Giardia and Cryptosporidium by clarification(either dissolved-air flotation [DAF] or lamella [plate] sedimentation) and bydual-media filtration following clarification. Studies were conducted forchallenge conditions of cysts and oocysts (i.e., high influent concentrations)and for process design detention times and hydraulic loadings. To evaluate theeffect of water temperature on performance, sets of experiments were performedfor winter and spring seasons. DAF clarification performed better than lamellasedimentation and consistently resulted in lower turbidity levels and particlecounts. Overall log removals of Giardia and Cryptosporidium by clarification andfiltration were about the same for DAF versus lamella sedimentation. AlthoughDAF is not recognized under the Surface Water Treatment Rule or the InterimEnhanced Surface Water Treatment Rule, the authors argue that based on thesefindings, DAF plants should receive Giardia and Cryptosporidium removal creditsat least equal to those received by sedimentation plants. Includes 18 references, tables, figures.

Product Details

Edition:

Vol. 92 - No. 12

Published:

12/01/2000

Number of Pages:

15

File Size:

1 file , 290 KB