Microbiological processes in drinking water (Contact:Hans-Jørgen Albrechtsen, Erik Arvin and Barth F. Smets)
Biofilm processes and bulk phase interactions including growth rates, decay and detachment are quantified for drinking water systems. The controlling factors for the biofilm formation include the composition of the microbial community, substratum, hydraulics, presence of biocides (e.g. chlorine), and the substrate available. In addition, we are developing individual-based predictive mechanistic models for biofilm growth and dynamics using the iDynoMiCS platform. These models are being validated with test strains in model flow-through biofilms. Investigations are conducted in laboratory and bench scale model distribution systems.
Microbiology of distribution systems and household installations (Contact: Hans-Jørgen Albrechtsen)
The structure, composition, diversity and development over time (maturing) of indigenous microbial communities is studied in drinking water distribution systems. Molecular based methods (e.g. clone libraries) are used to compare the microbial population in bulk water and in biofilms. The importance of biofilms for the survival and fate of intruding indicator organisms (E. coli, and coliforms, (e.g. Klebsiella pneumophila) and pathogens (e.g. Campylobacter jejuni) and the occurrence of small animals and their interaction with the microbiology is also investigated. Potential long retention times, increased temperatures and a wide range of materials may facilitate microbial growth in household installations. This is investigated in cold water as well as hot water installations, where biofilm is of concern, e.g. because it may provide a safe haven for the bacteria Legionella.
Modelling of processes in distribution systems (Contact: Erik Arvin)
The hydraulic models available for water distribution systems are very advanced. However, they have a poor capability of modelling chemical and biological transformation processes. The present work aims at developing transformation process models for antioxidants and their degradation products in polymer pipes. This includes models for migration of the organic compounds in the polymer pipes and in the water diffusion layer attached to the pipes and transformation processes in the bulk water. Afterwards, these models have to be integrated in modelling platforms, for example EPANET and commercial platforms.