Fate and transport modelling of microbial pollution in a lake used as a drinking water source

Paper in proceeding, 2011

Faecal contamination of drinking water sources can cause outbreaks of waterborne disease. In this study a modelling approach is used to investigate the risk of contaminated raw water for the intake to the drinking water treatment plant posed by wastewater discharges in Lake Rådasjön in Gothenburg, Sweden. Microbial pollution is studied using the traditional faecal indicator organism E. coli and virus indicator somatic coliphages. Transport of faecal indicators is simulated using the three-dimensional hydrodynamic model MIKE3, and inactivation processes are described by the ecological module ECOLab. The ecological model is calibrated against decay curves obtained from microcosm experiments with lake water performed under natural conditions. The risks on drinking water supply and critical hydrometeorological situations that can cause low quality of raw water have been identified. This information provides input for further risk assessment of the entire drinking water supply system.