title: Modelling the influence of total suspended solids on E. coli removal in river water.
abstract: Following sewer overflows, fecal indicator bacteria enter surface waters and may experience different lysis or growth processes. A 1D mathematical model was developed to predict total suspended solids (TSS) and Escherichia coli concentrations based on field measurements in a large-scale flume system simulating a combined sewer overflow. The removal mechanisms of natural inactivation, UV inactivation, and sedimentation were modelled. For the sedimentation process, one, two or three particle size classes were incorporated separately into the model. Moreover, the UV sensitivity coefficient α and natural inactivation coefficient kd were both formulated as functions of TSS concentration. It was observed that the E. coli removal was predicted more accurately by incorporating two particle size classes. However, addition of a third particle size class only improved the model slightly. When α and kd were allowed to vary with the TSS concentration, the model was able to predict E. coli fate and transport at different TSS concentrations accurately and flexibly. A sensitivity analysis revealed that the mechanisms of UV and natural inactivation were more influential at low TSS concentrations, whereas the sedimentation process became more important at elevated TSS concentrations.
authors.affiliation: Karlsruhe Institute of Technology, Engler-Bunte-Institut, Chair of Water Chemistry and Water Technology, Engler-Bunte-Ring 9, 76131 Karlsruhe, Germany E-mail: jueying.qian@partner.kit.edu.
authors.forename: Jueying
authors.initials: J
authors.lastname: Qian
authors.affiliation: Technische Universität München, Chair of Urban Water Systems Engineering, Am Coulombwall, 85748 Garching, Germany and Temple University, College of Engineering, Civil and Environmental Engineering, Philadelphia, PA 19122, USA.
authors.forename: Evelyn
authors.initials: E
authors.lastname: Walters
authors.affiliation: Technische Universität München, Chair of Hydraulic and Water Resources Engineering, Arcisstr. 21, 80333 München, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Rutschmann
authors.affiliation: Karlsruhe Institute of Technology, Engler-Bunte-Institut, Chair of Water Chemistry and Water Technology, Engler-Bunte-Ring 9, 76131 Karlsruhe, Germany E-mail: jueying.qian@partner.kit.edu; Karlsruhe Institute of Technology, Institute of Functional Interfaces, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Wagner
authors.affiliation: Karlsruhe Institute of Technology, Engler-Bunte-Institut, Chair of Water Chemistry and Water Technology, Engler-Bunte-Ring 9, 76131 Karlsruhe, Germany E-mail: jueying.qian@partner.kit.edu.
authors.forename: Harald
authors.initials: H
authors.lastname: Horn
mesh_terms: D004926:Escherichia coli / Q000502:physiology*; D005243:Feces / Q000382:microbiology; D008954:Models, Biological; D008956:Models, Chemical; D045483:Rivers / Q000737:chemistry / Q000382:microbiology*; D014871:Water Microbiology; D018508:Water Purification