Grantee Research Project Results

2011 Progress Report: Association of Pathogens with Biofilms in Drinking Water Distribution Systems

EPA Grant Number: R834870
Title: Association of Pathogens with Biofilms in Drinking Water Distribution Systems
Investigators: Nguyen, Thanh (Helen) H. , Hozalski, Raymond , Liu, Wen-Tso
Institution: University of Illinois Urbana-Champaign , University of Minnesota
EPA Project Officer: Packard, Benjamin H
Project Period: June 1, 2011 through May 28, 2016
Project Period Covered by this Report: June 1, 2011 through May 31,2012
Project Amount: $600,000
RFA: Advancing Public Health Protection through Water Infrastructure Sustainability (2009) RFA Text | Recipients Lists
Research Category: Drinking Water , Water

Objective:

To focus on addressing the public health risk due to waterborne pathogen contamination of the distribution system.
To identify the factors that influence the persistence of a model pathogen, Legionella, in multi-species biofilms grown on different pipe materials under conditions relevant to distribution systems.
To use molecular biology and surface chemistry tools to characterize the microbial communities and the surface properties of the biofilms, respectively.
To further investigate novel chemical and enzymatic treatments to weaken the biofilm to promote detachment and improved cleaning.

Progress Summary:

Methodology for biofilm growth from groundwater, which is source for drinking water in Urbana, IL, and from dechlorinated tap water has been established.
Biofilms are characterized for physical and microbial structure, and chemical composition.
Legionella ATTC strain has been tagged with GFP plasmid so that deposition of fluorescence cells on biofilms can be modified.
We found that the mechanisms of E. coli attachment to groundwater biofilm change depending of the age of the biofilms. The physico-chemical properties of the water (ionic strength, hardness) govern the deposition rate of E.coli cells on PVC plates and on young/thin biofilms (age < 8 weeks). An increasing ionic strength/hardness increases the deposition rates. The physical biofilm properties govern E.coli cell attachment in the case of mature biofilms (age > 16 weeks). An increasing biofilm roughness increases the deposition rate.
A crystal violet assay is being used to assess the effect of treatment chemicals on biofilm detachment

Future Activities:

Biofilms will be grown from groundwater and dechlorinated tap water
Biofilms will be characterized as planned and the characteristics will be used to explain the deposition data.
Deposition of Legionella on biofilms grown before and after exposure to disinfectants will be conducted.
Detachment of biofilms exposed to different chemicals will be determined.

Journal Articles:

No journal articles submitted with this report: View all 8 publications for this project

Supplemental Keywords:

drinking water, pathogen

Progress and Final Reports:

Original Abstract

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.