www.epa.gov
science BRIEF
BUILDING A SCIENTIFIC FOUNDATION FOR SOUND ENVIRONMENTAL DECISIONS
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National Risk Management
Research Laboratory
www.epa.gov/nrmrl/
Aging Water Infrastructure Research Program
Addressing the Challenge Through Innovation
Condition Assessment of Collection Systems
"Our nation's extensive water
infrastructure has the capacity to
treat, store, and transport trillions
of gallons of water and wastewater
per day through millions of miles
of pipelines. However, as our
infrastructure deteriorates, there
are increasing concerns about
the ability of this infrastructure
to keep up with our future needs."
George Gray, Ph.D.
Assistant Administrator for
Research and Development
United States Environmental
Protection Agency
EPA has begun a new research program
intended to generate the science and
engineering that will address our aging
water infrastructure. The program,
entitled "Innovation and Research
for Water Infrastructure for the 21st
Century," calls for research relating
to system rehabilitation, advanced
concepts, and condition assessment.
To assess the condition of a collection
system, data and information are gathered
through observation, direct inspection,
investigation, and indirect monitoring
and reporting. An analysis of the data and
information helps determine the structural,
operational, and performance status of
capital infrastructure assets. Condition
assessment also includes failure analysis
to determine the causes of infrastructure
failures and to develop ways to prevent
future breakdowns. Condition assessment
enhances the ability of utilities to make
technically sound judgments regarding
asset management.
Current Issues
There are several concerns related
to condition assessment of collection
systems. Since the Clean Water Act
was passed in 1972, sewer system
condition assessment has focused on
the reduction of:
• Infiltration - ground water that enters
a sewer system through pipe leaks
• Inflow - water that flows into a sewer
system through improper connections,
such as downspouts, sump pumps,
and manhole covers
Excessive infiltration and inflow must
be conveyed and treated; too much of this
infiltration and inflow in a sewer system
can cause backups and system overflows,
and peak-flow treatment at wastewater
treatment plants becomes challenging.
Deterioration of a wastewater collection
system can result in infiltration of ground
water and the export of recharge water
from watersheds. This situation, when
combined with the impervious surfaces
found in urban and suburban areas,
reduces flows in streams, which can
adversely affect aquatic ecosystems
and reduce water availability.
A universal challenge for wastewater
utilities is corrosion of the collection
infrastructure. Specifically, sulfuric
acid corrosion negatively affects
concrete surfaces, mortar, and metal
reinforcement material. To address this
issue, it's important to identify the extent
of the pipe corrosion, where corrosion
could happen, and the best resolution
(i.e., rehabilitation, repair, retrofitting,
or replacement).
State of the Technology
Comprehensive asset management is
broadening the focus of sewer system
condition assessment to include the
likelihood and consequences of capital
infrastructure deterioration and failure.
The current state of the technology in
the area of inspection and condition
assessment is the ability to visually
examine the internal condition of a
gravity sewer using internal cameras,
usually closed circuit television (CCTV).
Most utilities employ a rating system that
uses the results from CCTV investigations
to make an overall assessment of each
section of sewer. The rating can be
combined with other data and information
to determine maintenance and system
rehabilitation priorities.
Inspection technologies using
sonar, laser, ultrasonic, and infrared
(technologies not traditionally applied
to sewer system investigation) are
emerging with concurrent advances
in digital, modular, and robotics
technologies.
U.S. Environmental Protection Agency
Office of Research and Development, National Risk Management Research Laboratory
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New Research
Beginning in fiscal year 2007, EPA's new
research program will initiate projects
that address inspection and condition
assessment in the following areas:
• Assess State of the Technology
- Convene technology forum
- Develop state-of-the-technology
capsule reports
o Internal camera inspection
o Advanced integrity monitoring
• Conduct Technology demonstration
studies
- Develop protocols and metrics
for field demonstrations
- Determine site selection criteria
for field demonstrations
- Initiate field demonstrations
The Door Is Open for
Collaboration
EPA, whose primary role is that
of advocate for a sustainable water
infrastructure, is only one partner in
this effort. The Aging Water Infrastructure
research program presents opportunities
for utilities, vendors, researchers,
academics, water associations (trade
and professional), and other agencies
and organizations to collaborate.
In fact, the success of the program
depends on stakeholder involvement,
sharing information and tools, and
working together toward the long-term
stewardship of our water infrastructure.
CONTACT
Daniel J. Murray, Jr., P.E.,
Senior Environmental Engineer
Office of Research and Development
U.S. Environmental Protection Agency
National Risk Management Research Laboratory
(513)569-7522
murray.dantoiepa. gov
REFERENCES
Sustainable Infrastructure for Water and Wastewater
http://www.epa.gov/waterinfrastructure/index.html
U.S. EPA. (2007). "Innovation and Research for
Water Infrastructure for the 21st Century, Research
Plan." April 30.
U.S. EPA. (2007). Statement of George Gray,
Ph.D., Assistant Administrator for Research and
Development and EPA Science Advisor, before
the Subcommittee on Energy and the Environment,
Committee on Science and Technology, United States
House of Representatives. March 14.
Recycled/Recyclable
Printed with vegetable-based ink on
paper that contains a minimum of
50% post-consumer fiber content
processed chlorine free
U.S. Environmental Protection Agency
Office of Research and Development, National Risk Management Research Laboratory
EPA/600/F-07/014
September 2007
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