Microbiome of Drinking Water Distribution Systems

Abstract

Drinking water distribution systems appear as vulnerable engineered systems constantly sown and colonized by microorganisms representing several hundreds of species. Such microorganisms originate firstly from finished potable drinking water, secondly from growth in the distribution systems in the bulk water and on the surface of pipes and reservoirs as biofilms, and thirdly from accidental or continuously low introduction of pathogens. This biomass is a source of technological problems (microbiologically influenced corrosion, red water, odor, and taste of tap water) caused by some specific microbes. Investigation and control of the microbial population community and its behavior in drinking water distribution systems should be the cornerstone of efforts to protect distribution system integrity, water quality, and public health. This silent contamination could also be responsible for endemic gastrointestinal illnesses attributable to tap water meeting current standards. As shown throughout this literature review (mainly limited to papers published from 1990 to 2014), distribution systems must be considered as bioreactors. First, we present bugs systematically found in drinking water distribution systems all over the world (bacteria, viruses, yeasts, fungi, protozoa, microcrustaceans, rotifers, and oligochaete worms). Then, we analyze and discuss several items related to biofilms grown under conditions relevant to drinking water environments including mechanisms of biofilm formation, structure, cohesiveness, biodiversity, and pathogen reservoirs. Finally, the chapter concludes with a review of some of the parameters governing biofilm accumulation in drinking water distribution systems.