Work

Succession of bacterial biofilm communities following removal of chloramine from a full-scale drinking water distribution system

Year: 2023

Type: article

Abstract: Monochloramine is used to regulate microbial regrowth in drinking water distribution systems (DWDS) but produces carcinogenic disinfection byproducts and constitutes a source of energy for nitrifying bacteria. This study followed biofilm-dispersed microbial communities of a full-scale DWDS distributing ultrafiltered water over three years, before and after removal of monochloramine. Communities were described using flow cytometry and amplicon sequencing, including full-length 16S rRNA gene sequencing. Removal of monochloramine increased total cell counts by up to 440%. Increased abundance of heterotrophic bacteria was followed by emergence of the predatory bacteriaBdellovibrio, and a community potentially metabolizing small organic compounds replaced the nitrifying core community. No increased abundance ofMycobacteriumorLegionellawas observed. Co-occurrence analysis identified a network ofNitrosomonas,Nitrospira,SphingomonasandHyphomicrobium, suggesting that monochloramine supported this biofilm community. While some species expanded into the changed niche, no immediate biological risk to consumers was indicated within the DWDS.

Source: npj Clean Water

DOI: 10.1038/s41545-023-00253-x