Institute of Hydraulic Engineering and Water Resources Management

Vienna, Austria

Institute of Hydraulic Engineering and Water Resources Management

Vienna, Austria
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Derx J.,Institute of Hydraulic Engineering and Water Resources Management | Derx J.,Vienna University of Technology | Blaschke A.P.,Institute of Hydraulic Engineering and Water Resources Management | Blaschke A.P.,Vienna University of Technology | And 6 more authors.
Journal of Contaminant Hydrology | Year: 2013

Riverbank filtration is an effective process for removing pathogenic viruses from river water. Despite indications that changing hydraulic conditions during floods can affect the efficacy of riverbank filtration to remove viruses, the impact on advection and dispersion of viruses in the riverbank is not well understood. We investigated the effects of fluctuations in river water level on virus transport during riverbank filtration, considering 3-D transient groundwater flow and virus transport. Using constant removal rates from published field experiments with bacteriophages, removal of viruses with distance from the riverbank was simulated for coarse gravel, fine gravel and fine sandy gravel. Our simulations showed that, in comparison with steady flow conditions, fluctuations in river water level cause viruses to be transported further at higher concentrations into the riverbank. A 1-5 m increase in river water levels led to a 2- to 4-log (log10 reduction in concentration relative to the initial concentration in the river) increase in virus concentration and to up to 30 % shorter travel times. For particular cases during the receding flood, changing groundwater flow conditions caused that pristine groundwater was carried from further inland and that simulated virus concentrations were more diluted in groundwater. Our study suggests that the adverse effect of water level fluctuations on virus transport should be considered in the simulation of safe setback distances for drinking water supplies. © 2013 Published by Elsevier B.V.


Motamedi A.,Isfahan University of Technology | Motamedi A.,Graz University of Technology | Afzalimehr H.,Isfahan University of Technology | Zenz G.,Institute of Hydraulic Engineering and Water Resources Management
European Journal of Scientific Research | Year: 2011

Acoustic Doppler Velocimeters (ADV) experiments have been conducted over a fixed-dune to examine the effects of interacting dunes on the flow structure. The shape, dimensions and side angle of selected dunes were based upon previous empirical and field studies of dune morphology. Experiments were carried out on flow over a train of fixed 2D rough wall dunes in 12m flume. Dunes are developed in the height of 4 and 8 cm and in wavelength of 1m. This paper investigate the effect of lee angle (steep (>20°) and low (<10°) lee side angles) on separation zone and to study the effect of the dune bed roughness on turbulence structures and the length of separation zone calibrated RANS simulations was compared with experimental data. It is found that the models provide a good overall description measured by ADV. The separation zone also has a strong relation with lee angle and in the situation of low lee angle no flow separation was detected. Also increasing the dune height, roughness, water depth or velocity don't have an effective impact to separate the flow near the crest. © 2011 EuroJournals Publishing, Inc.


PubMed | Institute of Hydraulic Engineering and Water Resources Management
Type: | Journal: Journal of contaminant hydrology | Year: 2013

Riverbank filtration is an effective process for removing pathogenic viruses from river water. Despite indications that changing hydraulic conditions during floods can affect the efficacy of riverbank filtration to remove viruses, the impact on advection and dispersion of viruses in the riverbank is not well understood. We investigated the effects of fluctuations in river water level on virus transport during riverbank filtration, considering 3-D transient groundwater flow and virus transport. Using constant removal rates from published field experiments with bacteriophages, removal of viruses with distance from the riverbank was simulated for coarse gravel, fine gravel and fine sandy gravel. Our simulations showed that, in comparison with steady flow conditions, fluctuations in river water level cause viruses to be transported further at higher concentrations into the riverbank. A 1-5 m increase in river water levels led to a 2- to 4-log (log10 reduction in concentration relative to the initial concentration in the river) increase in virus concentration and to up to 30% shorter travel times. For particular cases during the receding flood, changing groundwater flow conditions caused that pristine groundwater was carried from further inland and that simulated virus concentrations were more diluted in groundwater. Our study suggests that the adverse effect of water level fluctuations on virus transport should be considered in the simulation of safe setback distances for drinking water supplies.

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