Resuspension and Attachment of PhiX174 in Sediment Laden Flow

Abstract

To improve the understating of viral pathogens’ resuspension from bed sediment and their attachment to suspended sediment, a series of flume experiments using a coliphage surrogate, PhiX174, were conducted with two sediments: sand and sandy loam. Using this data, a conceptual model was developed that quantifies the resuspension rate using a dynamic virus-sediment attachment ratio. The resuspension flux was calculated as the product of virus concentrations in bed sediment and the resuspension velocity. Two resuspension models were derived for the sediments with and without cohesive material. The resulting models correlated nondimensional bed shear stress with the virus concentration in the water. Predictions of the models satisfactorily matched the observed virus concentration. The results shed light on the underlying physics of the attachment of virus to sediment. The attachment ratio increases with bed shear stress until reaching the critical shear stress, and then decreases with a further increase of bed shear stress. Moreover, the virus reverses its attachment to sediment particles after reaching the critical condition for sediment incipient motion. The conceptual model as well as the experimental data shed light on the key processes governing the fate and transport of viral pathogens in sediment laden flow.