HR: 08:25h
AN: H41H-02    [Abstracts]
TI: Long-Term Transport of Cryptosporidium Parvum
AU: * Andrea, C
EM: acortis@ucdavis.edu
AF: Department of Land, Air and Water Resources, University of California Davis, 229 Veihmeyer Hall, Davis, CA 95616-8628 United States
AU: Harter, T
EM: thharter@ucdavis.edu
AF: Department of Land, Air and Water Resources, University of California Davis, 229 Veihmeyer Hall, Davis, CA 95616-8628 United States
AU: Hou, L
EM: lhou@vmtrc.ucdavis.edu
AF: Department of Population Health & Reproduction VMTRC-Tulare University of California Davis, Room 4, Veterinary Medicine Teaching and Research Center 18830 Road 112 Tulare, Tulare, CA 93274 United States
AU: Atwill, E R
EM: ratwill@vmtrc.ucdavis.edu
AF: Department of Population Health & Reproduction VMTRC-Tulare University of California Davis, Room 4, Veterinary Medicine Teaching and Research Center 18830 Road 112 Tulare, Tulare, CA 93274 United States
AU: Packman, A
EM: a-packman@northwestern.edu
AF: Department of Civil and Environmental Engineering, Northwestern University, A314 Technological Institute, 2145 Sheridan Road, Evanston, IL 60208-3109 United States
AU: Woodrow-Mumford, K
H41H-02 AF: Department of Population Health & Reproduction VMTRC-Tulare University of California Davis, Room 4, Veterinary Medicine Teaching and Research Center 18830 Road 112 Tulare, Tulare, CA 93274 United States
AU: Maldonado, S
H41H-02 AF: Department of Population Health & Reproduction VMTRC-Tulare University of California Davis, Room 4, Veterinary Medicine Teaching and Research Center 18830 Road 112 Tulare, Tulare, CA 93274 United States
AB: The protozoan pathogen Cryptosporidium parvum is a leading cause of waterborne disease. Subsurface transport and filtration in natural and artificial porous media are important components of the environmental pathway of this pathogen. It has been shown that the oocysts of C. parvum show distinct colloidal properties. We conducted a series of laboratory studies on sand columns (column length: 10 cm - 60 cm, flow rates: 0.7 m/d - 30 m/d, ionic strength: 0.01 - 100 mM, filter grain size: 0.2 - 2 mm, various solution chemistry). Breakthrough curves were measured over relatively long time-periods (hundreds to thousands of pore volumes). We show that classic colloid filtration theory is a reasonable tool for predicting the initial breakthrough, but it is inadequate to explain the significant tailing observed in the breakthrough of C. parvum oocyst through sand columns. We discuss the application of the Continuous Time Random Walk approach to account for the strong tailing that was observed in our experiments. The CTRW is generalized transport modeling framework, which includes the classic advection-dispersion equation (ADE), the fractional ADE, and the multi-rate mass transfer model as special cases. Within this conceptual framework, it is possible to distinguish between the contributions of pore-scale geometrical (physical) disorder and of pore-scale physico-chemical heterogeneities (e.g., of the filtration, sorption, desorption processes) to the transport of C. parvum oocysts.
DE: 0466 Modeling
DE: 4809 Colloids
DE: 7859 Transport processes
SC: Hydrology [H]
MN: Fall Meeting 2005