Managing microbial quality of drinking water in buildings

Bio

Frederik Hammes leads the Drinking Water Microbiology group at Eawag (The Swiss Federal Institute of Aquatic Science and Technology). The group’s research focuses on the microbial ecology and microbial dynamics of drinking water treatment and distribution systems from source-to-tap. They specialize in the development and application of quantitative, standardized and automated applications of flow cytometry for drinking water analysis, to replace conventional culture-based approaches. They furthermore focus on understanding microbial biofilm growth on materials in contact with drinking water in building plumbing systems, and mitigating the consequences thereof.

Abstract

Complex microbial biofilms including opportunistic pathogens assemble in the drinking water plumbing systems of buildings. As a consequence, the passage of drinking water through building plumbing change the microbial composition of the water, leading in some cases to severe aesthetic and hygienic water quality deterioration. Here, biofilm assembly is predominantly governed by the ecological processes of dispersal and selection. We propose that the varying environmental conditions in different sections of the built environment  is a key driver of selection during biofilm assembly, resulting in spatially heterogenous biofilms. This presentation will revisit some of the basic concepts of biofilm formation and development, focussing on drinking water biofilms that assemble on synthetic polymeric  materials. We assess the role of continuous carbon migration from the material, relative to aperiodic inorganic nutrient supply from the water as a result of stagnation and flushing. Furthermore, the influence on  biofilm thickness, microbial community composition and the presence of opportunistic pathogens will be discussed. Finally, some mitigating strategies for managing microbial communities in plumbing systems will be considered, such as testing, grading and use of high quality plumbing materials and sensible operation of water distribution systems on building scale.