Attenuation of Pathogen Shock Load: Analytical Analysis of Infiltration Gallery in Riverbank Filtration during Stream Stage Rise

Abstract

A risk assessment model was developed and combined with hydrogeological data to determine the permissible limit of fecal coliform in water during riverbank filtration (RBF). It combined an analytical solution of water flow and contaminant transport from a stream to an infiltration gallery. The model was developed to simulate stream stage rise conditions and monitor harmful pathogens during infiltration. The analytical element method (AEM) was used to measure the travel time of water toward the gallery for a given rise in stream stage under an unsteady state of flow condition. To study the contaminant concentration variation, pathogen transport considering dispersion and decay was analyzed. Pathogen transport in groundwater was simulated using a logistic function that integrates an AEM. To achieve the objective of an appropriate location of an infiltration gallery, the desired reduction of pathogen concentration was evaluated. The analysis for optimum distance with various trials of water travel time is also presented. This study examined the potential of RBF systems for an infiltration gallery considering its safe distance against pathogen shock load during the storm. However, further biogeochemical modeling is needed to predict the fate of contaminants during their transit to the infiltration gallery.