Understanding, Monitoring, and Controlling Biofilm Growth in Drinking Water Distribution Systems

Abstract

ABSTRACT:In drinking water distribution systems (DWDS), biofilms are the predominant 1 mode of microbial growth with the presence of extracellular polymeric substance (EPS) 2 protecting the biomass from environmental and shear stresses. Biofilm formation poses a 3 significant problem to the drinking water industry as a potential source of bacterial 4 contamination, including pathogens and in many cases also affecting the taste and odor of 5 drinking water and promotes corrosion of pipes. This article critically reviews important 6 research findings on biofilm growth in DWDS, examining the factors affecting their 7 formation and characteristics, as well as the various technologies to characterize, monitor and 8 ultimately, to control their growth. Research indicates that temperature fluctuations 9 potentially affect not only the initial bacteria-to-surface attachment but also the growth rates 10 of biofilms. For the latter, the effect is unique for each type of biofilm-forming bacteria -11 ammonia oxidizing bacteria for example, grow more developed biofilms at typical summer 12 temperature of 22C compared to 12C in fall , while the opposite occurs for the pathogenic 13 RNA, EPS, protein and lipid stains) and electron microscopy imaging (ESEM). Importantly, 24 thorough identification of microbial fingerprints in drinking water biofilms is achievable with 25 3

A Keystone Methylobacterium Strain in Biofilm Formation in Drinking Water

“…Thus, part of our study here was focused on bacterial aggregation in drinking water under stagnant conditions. Motility, stress, and quorum sensing are all known to play an important role in triggering the switch from planktonic to biofilm mode of life in bacteria [70,71]. In the oligotrophic conditions in DWDS, where chemical stresses like chlorination are imposed, biofilms unsurprisingly seem to be the favoured mode of life for microorganisms.…”

Online characterization of bacterial processes in drinking water systems

“…Bacterial growth in the DWDSs is attributed to numerous aspects, including the amount of nutrient present for growth (e.g., biodegradable dissolved organic carbon), oxidant residuals, presence of predators, presence of corrosion, and operational conditions (e.g., feed water temperature and flow regimes) 4,12 . Bacterial growth in DWDS can be controlled by adding a disinfectant such as chlorine, chlorine dioxide, and monochloramine before distribution of drinking water in concentrations that would maintain a disinfectant residual in DWDS or by limiting growth-promoting nutrients in the water 4,13 .…”

Nitrification in Premise Plumbing: A Review

“…Biofilms form in DWDSs along the pipe wall through a series of stages including: attachment, extracellular polymeric substances (EPS) development, cell proliferation, maturation, and finally detachment [46]. Biofilms constitute a majority of the bacterial concentrations in DWDS and provide an environment where different bacterial species can survive cooperatively [47][48][49][50].…”