Mid Sweden University

This master’s thesis is being carried out in the context of E. coli in the environment and to learn more about this bacterium that is now emerging in oligotrophic water bodies in the north of Sweden. The study is part of the ECWA-NOR project (E.coli as Indicator for Sustainable Water Management in Northern Oligotrophic Rivers) carried out at Mid Sweden University. An aspect of this project that was focused on in this study is to investigate the potential effect of physicochemical river properties on the inactivation rate of E. coli. The first step was to start constructing the method for laboratory experimenting, based on literature and in-house knowledge. Afterwards, an experiment was performed according to the predesigned method. Based on the results and experiences during this experiment, improvements to the method could be suggested, which resulted in a laboratory method for simulating the effect of different temperature and colour levels on the inactivation rate of a specific E. coli strain. On top of this method development, there were results from the experiments that were interpreted and integrated into the ongoing ECWA-NOR research. UV was found to have a very big impact on E. coli inactivation, which was underestimated prior to developing the experiment.