Harmful microbes found on sewer pipe walls

Date:
July 6, 2020
Source:
Rutgers University
Summary:
Can antibiotic-resistant bacteria escape from sewers into waterways
and cause a disease outbreak? A new study examined the microbe-laden
''biofilms'' that cling to sewer walls, and even built a simulated
sewer to study the germs that survive within.



FULL STORY ==========================================================================
Can antibiotic-resistant bacteria escape from sewers into waterways and
cause a disease outbreak?

==========================================================================
A new Rutgers study, published in the journal Environmental Science:
Water Research & Technology, examined the microbe-laden "biofilms"
that cling to sewer walls, and even built a simulated sewer to study
the germs that survive within.

They found that these biofilms often contain harmful, antibiotic-resistant bacteria and can withstand standard treatment to disinfect
sewers. Cleaning with bleach can reduce the density of biofilms but not entirely remove them, potentially leaving wastewater treatment workers
and the public exposed to health risks.

Still, disinfecting a sewer line may be a good idea before sewer
maintenance is done, especially following events such as a disease
outbreak or bioterrorism incident that might expose sewer lines to
high-risk microbes. Luckily, with respect to SARS-CoV-2, the coronavirus causing COVID-19, water and wastewater are not expected to be important transmission routes.

Normally, what's flushed down a toilet goes to a wastewater treatment
plant.

But rainfall can cause overflows of untreated waste into bays, rivers,
streams and other waterways. The researchers say a potential worst-case scenario would be an infectious disease outbreak following a sewer
overflow that releases wastewater, sewer solids and biofilms to surface
water.

"Given the current interest in wastewater-based epidemiology for
monitoring the coronavirus, our study highlights the need to consider
sewer processes and how best to combat pathogens," said senior author
Nicole Fahrenfeld, an associate professor in the Department of Civil
and Environmental Engineering in the School of Engineering at Rutgers University-New Brunswick. "We will work to repeat a portion of our
experiments to understand how long the coronavirus may linger in sewers
and if that will impact monitoring of it in wastewater." The researchers
found that sewer pipe materials (concrete or PVC plastic) did not affect
the formation of biofilms but played a role in the effectiveness of
bleach to disinfect them. Bleach is better at removing biofilms from
PVC than from concrete, likely because PVC is smoother.

The lead author is William R. Morales Medina, a Rutgers doctoral student.

Alessia Eramo, who earned a doctorate at Rutgers, and Melissa Tu,
a Rutgers undergraduate student, contributed to the study.


========================================================================== Story Source: Materials provided by Rutgers_University. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. William R. Morales Medina, Alessia Eramo, Melissa Tu,
N. L. Fahrenfeld.

Sewer biofilm microbiome and antibiotic resistance genes as
function of pipe material, source of microbes, and disinfection:
field and laboratory studies. Environmental Science: Water Research
& Technology, 2020; DOI: 10.1039/D0EW00265H ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200706094128.htm

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