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Removal Efficiencies and Attachment Coefficients for Cryptosporidium in Sandy Alluvial Riverbank Sediment
Citation:
FAULKNER, BART R., Y. OLIVAS, M. W. WARE, M. G. ROBERTS, J. F. GROVES, K. S. Bates, AND S. L. McCarty. Removal Efficiencies and Attachment Coefficients for Cryptosporidium in Sandy Alluvial Riverbank Sediment. WATER RESEARCH. Elsevier Science Ltd, New York, NY, 44(9):2725-2734, (2010).
Impact/Purpose:
Developing drinking water systems that employ riverbank filtration.
Description:
Riverbank filtration has been shown to be effective at removing viable Cryptosporidium parvum oocysts and, therefore, drinking water systems that employ riverbank filtration may receive additional treatment credits beyond that which they can obtain using traditional engineering approaches. In order to develop guidance for planning the construction of these systems, screening level predictive modeling by colloid filtration theory combined with advection and dispersion modeling is potentially very useful. Currently, only very few studies have measured basic effective colloid filtration parameters for naturally occurring riverbank sediments. In the focus of this study we conducted flow column experiments in triplicate and measured effective attachment rate coefficients for rivers of the Southern Great Plains which are sandy and low in organic matter. We found that for these high-energy rivers there was no apparent dependency of C. parvum removal with carbon content, bacterial colony forming units, or with gross texture properties of the sands. We observed no difference in removal efficiency even among sediments which would be commonly thought to have been affected by straining, versus ones which would not. First-order colloid attachment rate coefficients ranged between 4.17×10-5 and 6.63×10-4 min-1. Total log10 removals ranged from 8.97 to 79.17 m-1. These results have application for screening level colloid filtration modeling of riverbank filtration in these systems.
