Study of Bacterial Growth in Drinking Water Distribution Pipes as a Function of the Water Quality

This study examines the impact of water produced by membrane processes on bacterial dynamics within drinking water distribution systems. Employing a closed-loop pilot plant designed to replicate real-world conditions, the research focused on two primary objectives. First, it assessed the effects of different water compositions, which vary in their nutrient concentrations, including tap water, softened water, ultrafiltered water, and low-pressure reverse osmosis (LPRO) water, on bacterial development in pipes over successive 30-day phases. The findings indicated that water produced by LPRO, characterized by low nutrient levels, reduced microbial concentrations and altered the composition of bacterial communities, leading to the lowest overall bacterial counts during stationary phases. Second, the study investigated the behavior of established biofilms in response to changes in water type (tap water/LPRO water), revealing that after a certain duration, aging biofilms maintained their structural integrity and diversity despite variations in water quality. The presence of a robust biofilm could buffer the microbial community against drastic shifts associated with different water types, suggesting that pipe history plays a critical role in microbial dynamics within distribution systems. These results highlight the complex interplay between water quality and biofilm characteristics in the drinking water distribution systems.