Hydrodynamic Modelling of Microbial Water Quality in a Drinking Water Source

Paper in proceeding, 2013

The presence of faecal contamination in drinking water sources can cause waterborne disease outbreaks. The aim of this article was to study the influence of wastewater discharges from a wastewater treatment plant on microbial water quality in a drinking water source—the river Göta älv in Sweden. To fulfil this aim, the fate and transport of the faecal indicators E. coli and somatic coliphages in the river Göta älv were simulated using a three-dimensional hydrodynamic model. The validation of the hydrodynamic model confirmed a good model performance: the correlation coefficient was 0.99; the absolute mean difference between the simulated and measured water surface elevation was 0.03 m, which is 11.1 % of the standard deviation of the measured data. The modelling results revealed that during overflow events at the wastewater treatment plant, discharges of untreated wastewater contributed more to the concentrations of faecal indicators at the water intake than discharges of treated wastewater. The hydrodynamic modelling of microbial water quality proved to be a useful tool to estimate the contribution of different sources to the total contamination of raw water used for drinking water supply and, therefore, to provide decision-support information for preventive and mitigative risk-reduction measures.