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Impact of coagulation–ultrafiltration on long-term pipe biofilm dynamics in a full-scale chloraminated drinking water distribution system

Pullerits, Kristjan LU ; Chan, Sandy LU ; Ahlinder, Jon ; Keucken, Alexander LU ; Rådström, Peter LU and Paul, Catherine J. LU (2020) In Environmental Science: Water Research & Technology 6(11). p.3044-3056
Abstract
While pipe biofilms in DWDSs (drinking water distribution systems) are thought to affect the quality of distributed water, studies regarding the microbial processes are impeded by the difficulties in accessing biofilm undisturbed by DWDS maintenance. In this study, pipe sections were removed from a fully operational DWDS for biofilm sampling over two years and three months, and before and after start of ultrafiltration (UF) with coagulation treatment in the drinking water treatment plant (DWTP). Water (n = 31), surface biofilm (obtained by swabbing, n = 34) and deep pipe biofilm (obtained by scraping, n = 34) were analyzed with 16S rRNA gene amplicon sequencing; with flow cytometry, and chemical and natural organic matter (NOM) analysis as... (More)
While pipe biofilms in DWDSs (drinking water distribution systems) are thought to affect the quality of distributed water, studies regarding the microbial processes are impeded by the difficulties in accessing biofilm undisturbed by DWDS maintenance. In this study, pipe sections were removed from a fully operational DWDS for biofilm sampling over two years and three months, and before and after start of ultrafiltration (UF) with coagulation treatment in the drinking water treatment plant (DWTP). Water (n = 31), surface biofilm (obtained by swabbing, n = 34) and deep pipe biofilm (obtained by scraping, n = 34) were analyzed with 16S rRNA gene amplicon sequencing; with flow cytometry, and chemical and natural organic matter (NOM) analysis as additional parameters for water quality. UF with coagulation decreased the total cell concentration in the DWDS bulk water from 6.0 × 105 ± 2.3 × 105 cells per ml to 6.0 × 103 ± 8.3 × 103 cells per ml, including fluctuations due to seasonal change, as well as decreasing most analyzed fractions of NOM. UF treatment of the water revealed that 75% ± 18% of the cells in the water originated from DWDS biofilm, confirmed by SourceTracker analysis, with the rest of the cells likely released from biofilm on DWTP storage tanks. Following UF start, the ASVs (amplicon sequence variants) in the deep pipe biofilm decreased, and Evenness and Shannon diversity indices decreased, reflecting the community's response to the new environment created by the altered water quality. The pipe biofilm community was dominated by ASVs classified as Nitrosomonadaceae, Nitrospira, Hyphomicrobium and Sphingomonas, with relative abundances ranging from 5–78%, and also included ASVs of genus Mycobacterium, genus Legionella and order Legionellales. This community composition, together with the observation that turnover of nitrogen compounds was unchanged by UF start, indicate that nitrification in the DWDS was localized to the pipe biofilm. (Less)
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author
; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Biofilm
in
Environmental Science: Water Research & Technology
volume
6
issue
11
pages
3044 - 3056
publisher
Royal Society of Chemistry
external identifiers
  • scopus:85095451760
ISSN
2053-1419
DOI
10.1039/D0EW00622J
language
English
LU publication?
yes
id
07533a8f-9981-4632-b0fb-6b44e8a2f2c3
date added to LUP
2020-09-22 09:48:08
date last changed
2020-11-24 01:04:47
@article{07533a8f-9981-4632-b0fb-6b44e8a2f2c3,
  abstract     = {While pipe biofilms in DWDSs (drinking water distribution systems) are thought to affect the quality of distributed water, studies regarding the microbial processes are impeded by the difficulties in accessing biofilm undisturbed by DWDS maintenance. In this study, pipe sections were removed from a fully operational DWDS for biofilm sampling over two years and three months, and before and after start of ultrafiltration (UF) with coagulation treatment in the drinking water treatment plant (DWTP). Water (n = 31), surface biofilm (obtained by swabbing, n = 34) and deep pipe biofilm (obtained by scraping, n = 34) were analyzed with 16S rRNA gene amplicon sequencing; with flow cytometry, and chemical and natural organic matter (NOM) analysis as additional parameters for water quality. UF with coagulation decreased the total cell concentration in the DWDS bulk water from 6.0 × 105 ± 2.3 × 105 cells per ml to 6.0 × 103 ± 8.3 × 103 cells per ml, including fluctuations due to seasonal change, as well as decreasing most analyzed fractions of NOM. UF treatment of the water revealed that 75% ± 18% of the cells in the water originated from DWDS biofilm, confirmed by SourceTracker analysis, with the rest of the cells likely released from biofilm on DWTP storage tanks. Following UF start, the ASVs (amplicon sequence variants) in the deep pipe biofilm decreased, and Evenness and Shannon diversity indices decreased, reflecting the community's response to the new environment created by the altered water quality. The pipe biofilm community was dominated by ASVs classified as Nitrosomonadaceae, Nitrospira, Hyphomicrobium and Sphingomonas, with relative abundances ranging from 5–78%, and also included ASVs of genus Mycobacterium, genus Legionella and order Legionellales. This community composition, together with the observation that turnover of nitrogen compounds was unchanged by UF start, indicate that nitrification in the DWDS was localized to the pipe biofilm.},
  author       = {Pullerits, Kristjan and Chan, Sandy and Ahlinder, Jon and Keucken, Alexander and Rådström, Peter and Paul, Catherine J.},
  issn         = {2053-1419},
  language     = {eng},
  month        = {09},
  number       = {11},
  pages        = {3044--3056},
  publisher    = {Royal Society of Chemistry},
  series       = {Environmental Science: Water Research & Technology},
  title        = {Impact of coagulation–ultrafiltration on long-term pipe biofilm dynamics in a full-scale chloraminated drinking water distribution system},
  url          = {http://dx.doi.org/10.1039/D0EW00622J},
  doi          = {10.1039/D0EW00622J},
  volume       = {6},
  year         = {2020},
}