v>EPA
United States
Environmental Protection
Agency
Off ice of Water
Washington, D.C.
EPA 832-F-99-032
September 1999
Collection Systems
O&M Fact Sheet
Trenchless Sewer Rehabilitation
DESCRIPTION
As the infrastructure in the United States ages,
increasing importance is being placed on
rehabilitating the nation's wastewater treatment
collection systems. Cracks, settling, tree root
intrusion, and other disturbances that develop over
time deteriorate pipe lines and other conveyance
structures that comprise wastewater collection
systems. These deteriorating conditions can
increase the amount of inflow and infiltration (I/I)
entering the system, especially during periods of
wet weather. Increased I/I levels create an
additional hydraulic load on the system and thereby
decrease its overall capacity. In addition to I/I flow,
storm water may enter the wastewater collection
system through illegal connections such as down
spouts and sump pumps. If the combination of
wastewater, infiltration, and illegal storm water
connections entering the wastewater treatment
plant exceeds the capacity of the system at any
point, untreated wastewater may be released into
the receiving water. This bypass of untreated
wastewater, known as a Sanitary Sewer Overflow
(SSO), may adversely affect human health as well
as impair the usage and degrade the water quality of
the receiving water.
Under the traditional method of sewer relief, a
replacement or additional parallel sewer line is
constructed by digging along the entire length of the
existing pipeline. While these traditional methods
of sewer rehabilitation require unearthing and
replacing the deficient pipe (the dig-and-replace
method), trenchless methods of rehabilitation use
the existing pipe as a host for a new pipe or liner.
Trenchless sewer rehabilitation techniques offer a
method of correcting pipe deficiencies that requires
less restoration and causes less disturbance and
environmental degradation than the traditional dig-
and-replace method. Trenchless sewer
rehabilitation methods include:
• Pipe Bursting, or In-Line Expansion;
• Sliplining;
• Cured-In-Place Pipe; and
• Modified Cross Section Liner.
These alternative techniques must be fully
understood before they are applied. These four
sewer rehabilitation methods are described further
in the following sections.
Pipe Bursting or In-Line Expansion
Pipe bursting, or in-line expansion, is a method by
which the existing pipe is forced outward and
opened by a bursting tool. The Pipebursting™
method, patented by the British Gas Company in
1980, was successfully applied by the gas pipelines
industry before its applicability was identified by
other underground utility agencies. Over the last
two decades, other methods of in-line expansion
have been patented as well. During in-line
expansion, the existing pipe is used as a guide for
inserting the expansion head (part of the bursting
tool). The expansion head, typically pulled by a
cable rod and winch, increases the area available for
the new pipe by pushing the existing pipe radially
outward until it cracks. The bursting device pulls
the new pipeline behind itself. The pipe bursting
process is illustrated in Figure 1. Various types of
expansion heads, categorized as static or dynamic,
can be used on the bursting tool to expand the
existing pipeline. Static heads, which have no
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Source: Created by Parsons Engineering Science, Inc.,
1999.
FIGURE 1 THE PIPE BURSTING PROCESS
moving internal parts, expand the existing pipe only
through the pulling action of the bursting tool.
Unlike static heads, dynamic heads provide
additional pneumatic or hydraulic forces at the
point of impact. Pneumatic heads pulsate internal
air pressure within the bursting tool, while
hydraulic heads expand and collapse the head.
While the dynamic head pulsates or expands and
contracts, the bursting device is pulled through the
existing pipeline and breaks up the existing pipe,
replacing it with the new pipe directly behind it.
Dynamic heads are often required to penetrate
difficult pipe materials and soils. However,
because dynamic heads can cause movement of the
surrounding soils-resulting in additional pressure
and ground settlement-static heads are preferred
where pipe and soil conditions permit.
During the pipe bursting process, the rehabilitated
pipe segment must be taken out of service by re-
routing flows around it. After the pipe bursting is
completed, laterals are re-connected, typically with
robotic cutting devices.
Sliplining
Sliplining is a well-established method of trenchless
rehabilitation. During the sliplining process, a new
liner of smaller diameter is placed inside the
existing pipe. The annulur space, or area between
the existing pipe and the new pipe, is typically
grouted to prevent leaks and to provide structural
integrity. If the annulus between the sections is not
grouted, the liner is not considered a structural
liner. Continuous grouting of the annular space
provides a seal. Grouting only the end-of-pipe
sections can cause failures and leaks.
In most sliplining applications, manholes cannot
function as proper access points to perform the
rehabilitation. In these situations, an insertion pit
must be dug for each pipeline segment. Because of
this requirement, in most applications, sliplining is
not a completely trenchless technique. However,
the excavation required is considerably less than
that for the traditional dig-and-replace method.
System and site conditions will dictate the amount
of excavation spared.
Methods of sliplining include continuous,
segmental and spiral wound. All three methods
require laterals to be re-connected by excavation or
by a remote-cutter. In continuous sliplining, the
new pipe, joined to form a continuous segment, is
inserted into the host pipe at strategic locations.
The installation access point, such as a manhole or
insertion pit, must be able to handle the bending of
the continuous pipe section.
Installation by the segmental method involves
assembling pipe segments at the access point.
Sliplining by the segment method can be
accomplished without rerouting the existing flow.
In many applications, the existing flow reduces
frictional resistance and thereby aids in the
installation process. Spiral wound sliplining is
performed within a manhole or access point by
using interlocking edges on the ends of the pipe
segments to connect the segments. The spiral
wound pipe is then inserted into the existing pipe as
illustrated in Figure 2.
Cured-In-Place Pipe
During the cured-in-place pipe (CIPP) renewal
process, a flexible fabric liner, coated with a
thermosetting resin, is inserted into the existing
pipeline and cured to form a new liner. The liner is
typically inserted into the existing pipe through an
existing manhole. The fabric tube holds the resin in
place until the tube is inserted in the pipe and ready
to be cured. Commonly manufactured resins
include unsaturated polyester, vinyl ester, and
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Source: Created by Parsons Engineering Science, Inc., 1999.
FIGURE 2. SPIRAL WOUND SLIPLINING
PROCESS
epoxy, with each having distinct chemical
resistance to domestic wastewater.
The CIPP method can be applied to rehabilitate
pipe lines with defects such as cracks, offset joints,
and structurally deficient segments. The
thermosetting resin material bonds with the existing
pipe materials to form a tighter seal than most other
trenchless techniques. The two primary methods of
installing CIPP are winch-in-place and invert-in-
place. These methods are used during installation
to feed the tube through the pipe. The winch-in-
place method uses a winch to pull the tube through
the existing pipeline. After being pulled through
the pipeline, the tube is inflated to push the liner
against the existing pipe walls. The more typically
applied inversion-in-place method uses gravity and
either water or air pressure to force the tube through
the pipe and invert it, or turn the tube inside out.
This process of inversion presses the resin- coated
tube against the walls of the existing pipe. During
both the winch-in-place and inversion-in-place
methods, heat is then circulated through the tube to
cure the resin to form a strong bond between the
tube and the existing pipe. A typical CIPP process
by the water-inversion method is illustrated is
Figure 3.
Under both CIPP methods, as the liner expands to
fit the new pipe, dimples occur in the line where the
laterals exist. Dimples in the line can be found by
TV inspection or robotic equipment. In some
applications, a Tee is placed at the junction before
rehabilitation begins. Tee's enable junctions to be
easily identified and modified after the pipeline has
been re-lined. Laterals are typically reinstated with
robotic cutting devices, or, for large-diameter pipes,
by manually cutting the liner.
Modified Cross Section Lining
The modified cross section lining methods include
deformed and reformed methods, swagelining™,
and rolldown. These methods either modify the
pipe's cross sectional profile or reduce its cross-
sectional area so that the liner can be extruded
through the existing pipe. The liner is subsequently
expanded to conform to the existing pipe's size.
During deformed and reformed pipeline renewal, a
new flexible pipe is deformed in shape and inserted
into the host pipe. While the method of deforming
the flexible pipe varies by manufacturer, with many
processes referred to as fold and form methods, a
typical approach is to fold the new liner into a "U"
shape, reducing the pipe's diameter by about 30
percent. After the liner is pulled through the
existing line, the liner is heated and pressurized to
conform to the original pipe shape. A typical
deformed and reformed cross-section is illustrated
in Figure 4.
Another method of obtaining a close fit between the
new lining and existing pipe is to temporarily
compress the new liner before it is drawn through
the existing pipeline. The swagelining™ and
rolldown processes use chemical and mechanical
means, respectively, to reduce the cross-sectional
area of the new liner.
During swagelining™, a typical drawdown
process, the new liner is heated and subsequently
passed through a reducing die. A chemical reaction
between the die and liner material temporarily
reduces the liner's diameter by 7 percent to 15
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How Insituform® is installed
Figure 1. A special needled felt recon-
struction tube, Insitutube®, coated on
the outside, is custom engineered
and manufactured to fit the damaged
pipe exactly. It is impregnated with
a liquid thermosetting resin and low-
ered into a manhole through an inver-
sion tube. One end of the Insitu-
tube is firmly attached to the lower
end of the inversion tube elbow.
Figure 2. The inversion tube is then
filled with water. The weight of the
water pushes the Insitutube into the
damaged pipe and turns it inside out,
while pressing the resin impreg-
nated side firmly against the inside
walls of the old pipe. The smooth
coated side of the Insitutube becomes
the new interior surface of the pipe.
Figure 3. After the Insitutube is
inverted through the old pipe to the
desired length, the water is circulated
through a boiler. The hot water causes
the thermosetting resin to cure within a
few hours, changing the pliable Insitu-
tube into a hard, structurally sound,
pipe-within-a-pipe, Insitupipe™. It has
no joints or seams and is usually
stronger than the pipe it replaced. The
ends are cut off and the inversion tube
and scaffolding are removed. Normal-
ly, there are no messy excavation re-
pairs to be made since most work is
done without digging or disruption.
RESIN
IMPREGNATED
INSITUTUBE®
INVERSION TUBE
i/MANHOLE ss C
Source: Iseley and Najafi, 1995 (from Insituform®)
FIGURE 3 A TYPICAL CURED-IN-PLACE PIPE INSTALLATION PROCEDURE
percent and allows the liner to be pulled through the
existing pipe. As the new liner cools, it expands to
its original diameter. The rolldown process uses a
series of rollers to reduce the pipe liner's diameter.
As in deform-and-reform methods, heat and
pressure are applied to the expand the liner to its
original pipe diameter after it has been pulled
through the existing pipe.
Unlike CIPP, modified cross section methods do
not make use of resins to secure the liner in-place.
Lacking resin-coated lining, these methods do not
have the curing time requirement of CIPP. A tight
fit is obtained when the folded pipe expands to the
host pipe's inside diameter under applied heat and
pressure. As with the CIPP method, dimples are
formed at lateral junctions and similar methods of
reconnecting the laterals can be employed.
Materials typically used for modified cross section
linings include Polyvinyl Chloride (PVC) and High
Density Polyethylene (HOPE).
Trenchless sewer rehabilitation methods are now
routinely applied to wastewater collection system
improvement projects in the United States and
many other countries. Trenchless sewer
rehabilitation has been successfully applied by both
large municipalities such as New York, NY; Los
Angeles, CA; Boston, MA; Miami, FL; and
Houston, TX; and smaller municipalities such as
Baton Rouge, LA; Madison, WI; and Amarillo, TX.
Kramer and Thomson (1997) estimate that the
market value for sewer and pressure pipe
rehabilitation projects will be $5 billion dollars
world-wide in the year 2000.
In many municipalities, sewer rehabilitation
projects are an essential part of operation and
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FORMED
Source: Created by Parsons Engineering Science, Inc., 1999.
FIGURE 4 DEFORMED AND REFORMED
LINERS
maintenance (O&M) programs for the collection
system. For example, as part of an O&M program
focused on pro-active maintenance, Fairfax County,
Virginia, has identified two older sewersheds for
rehabilitation. All trunk and main lines within each
sewershed are television inspected. Results of the
TV inspection are used to prioritize cleaning needs
and to help determine appropriate rehabilitation
measures. Projects within the targeted sewersheds
have utilized the CIPP and fold-and-form
rehabilitation methods.
In an effort to monitor the effectiveness of the
rehabilitation efforts, the department installed
permanent and temporary meters in these two
sewersheds. Fairfax County's focused approach to
maintenance has reduced average flows to the
wastewater treatment plant (WWTP) despite several
years of above- normal rainfall.
APPLICABILITY
While trenchless techniques may be applied to
rehabilitate existing pipelines in a variety of
conditions, they are particularly valuable in urban
environments where construction impacts are
particularly disruptive to businesses, homeowners,
and automotive and pedestrian traffic. Other
underground utilities and existing infrastructure are
an obstacle in the traditional dig and replace
method, and trenchless techniques are widely
applied where these are present. Most trenchless
techniques are applicable to both gravity and
pressure pipelines. Many trenchless methods are
capable of performing spot repairs as well as
manhole to manhole lining.
For most applications, trenchless sewer
rehabilitation techniques require less installation
time-and therefore less pump-around time- than
traditional dig-and-replace methods. Installation
time can be critical in deciding between trenchless
sewer rehabilitation methods and dig- and-replace
methods. For example, when considering sewer
repair or replacement options for a critical force
main crossing the Elbe River in Heidenau,
Germany, city officials determined that the line
could not be out of service for more than 12 days
(Saccogna, 1998). As a result of this time
constraint, as well as reduced disruption to
riverboat traffic, city officials chose to rehabilitate
the sewer using the swagelining™ process. The
successfully rehabilitated sewer was out of service
only eight days.
Trenchless sewer rehabilitation can be performed to
increase the hydraulic capacity of the collection
system. While pipe bursting typically yields the
largest increase in hydraulic capacity, rehabilitation
by other trenchless methods may also increase
hydraulic capacity, by reducing friction. A
hydraulic analysis of the pre- and post-rehabilitation
conditions can be performed to evaluate the impact
on collection system capacity. In general, the
hydraulic analysis is performed by municipal
engineers and/or consultants who prepare
specifications for contractors.
Each of the trenchless rehabilitation methods
described has been used for various applications
over a range of pipe sizes and lengths. A
comparison of trenchless techniques is shown in
Table 1.
ADVANTAGES AND DISADVANTAGES
By reducing I/I levels in the collection system,
trenchless rehabilitation projects can assist
communities in complying with the EPA's Clean
Water Act and thereby protect the aquatic integrity
of receiving water-bodies from potentially high
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TABLE 1 A COMPARISON OF VARIOUS SEWER REHABILITATION TECHNIQUES
Method:
In-Line Expansion
Sliplining
Cured-ln-Place
Product Linings
Modified Cross-
Section Methods
Internal Point
Repair
Pipe Bursting
Segmental
Continuous
Spiral Wound
Inverted-ln-Place
Winched-ln-Place
Spray-on-Linings
Fold and Form
Deformed/Reformed
Drawdown
Rolldown
Thin-walled lining
Robotic Repair
Grouting/Sealing
& Spray-on
Link Seal
Point CIPP
Diameter Range (mm) Maximum Installation (m) Liner Material
100-600 (4-24 in.)
100 -4000 (4-1 58 in.)
100 -1600 (4-63 in.)
150 -2500 (6-100 in.)
100-2700 (4-1 08 in.)
100 -1400 (4-54 in.)
76-4500 (3-1 80 in.)
100-400 (4-1 5 in.)
100-400 (4-1 5 in.)
62-600 (3-24 in.)
62-600 (3-24 in.)
500-1, 100 (20-46 in.)
200-760 (8-30 in.)
N/A
100-600 (4-24 in.)
100-600 (4-24 in.)
230 (750 ft.)
300 (1,000 ft.)
300 (1,000 ft.)
300 (1,000 ft.)
900 (3, 000 ft.)
150 (500 ft.)
150 (500 ft.)
210 (700 ft.)
800 (2, 500 ft.)
300 (1,000 ft.)
300 (1,000 ft.)
960 (3, 000 ft.)
N/A
N/A
N/A
15 (50 ft.)
PE, PP, PVC, GRP
PE, PP, PVC, GRP
(-EP&-UP)
PE, PP, PE/EPDM,
PVC
PE, PVC, PP,
PVDF
Theromoset
Resin/Fabric
Composite
Theromoset
Resin/Fabric
Composite
Epoxy
Resins/Cement
Mortar
PVC
(thermoplastics)
HOPE
(thermoplastics)
HOPE, MDPE
HOPE, MDPE
HOPE
Exopy Resins
Cement Mortar
Chemical Grouting
Special Sleeves
Fiberglass/Polyester,
etc.
Note: Spiral wound slipling, robotic repair, and point CIPP can only be used only with gravity pipeline.
All other methods can be used with both gravity and pressure pipeline.
EPDM = Ethylene Polypelene Diene Monomer
GRP = Glassfiber Reinforced Polyester
HOPE = High Density Polyethylene
MDPE= Medium Density Polyethylene
PE = Polyethylene
PP = Polypropylene
PVC = Poly Vinyl Chloride
PVDF = Poly Vinylidene Chloride
Source: Iseley and Najafi (1995)
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pollutant concentrations by reducing SSOs. In
addition to potential improvements in receiving
water-bodies, trenchless sewer rehabilitation
requires substantially less construction work than
traditional dig-and-replace methods. In wetland
areas and areas with established vegetation,
construction influences can be especially harmful to
the plant and aquatic habitat. Underground utility
construction can disrupt citizens living and working
in areas near the construction zone. Trenchless
sewer rehabilitation, with the potential to reduce
surface disturbance over traditional dig- and-replace
methods, can reduce the number of traffic and
pedestrian detours, spare tree removal, decrease
construction noise, and reduce air pollution from
construction equipment. In addition to these
benefits, reducing the amount of underground
construction labor and surface construction zone
area confines work zones to a limited number of
access points, reducing the area where safety
concerns must be identified and secured.
Rehabilitation techniques should be selected based
on site constraints, system characteristics, and
project objectives. A comparison of economic,
cultural and social costs of sewer rehabilitation with
those of traditional dig-and-replace methods can
help determine whether or not a trenchless sewer
rehabilitation is suitable and economically feasible
for a particular site. Because some digging may be
required for point repairs, construction limitations
should be evaluated when deciding whether
trenchless sewer rehabilitation techniques can be
applied. If there are major changes in cross section
between manholes or if the existing alignment,
slope, or pipe bedding material must be changed,
each line must be rehabilitated as an independent
segment, necessitating even more digging. Specific
limitations of each trenchless rehabilitation method
are listed in Table 2. As seen, the sliplining,
deform-and- reform methods, and CIPP methods
will reduce the pipe diameter tending to decrease
the hydraulic capacity of the sewer. The
rehabilitated pipeline, however, may be less rough
than the original. The roughness coefficient
depending on the liner material. New high
performance plastic materials tend to reduce pipe
roughness against aged concrete materials.
Additionally, the hydraulic capacity may be
modified during rehabilitation as groundwater
intrusion is inadvertently redirected to unlined side
sewers. An evaluation may be performed to
determine whether the change in pipe friction and
TABLE 2 LIMITATIONS OF TRENCHLESS SEWER REHABILITATION
Method
Limitations
Pipe Bursting
Sliplining
CIPP
Modified Cross Section
Bypass or diversion of flow required
Insertion pit required
Percussive action can cause significant ground movement
May not be suitable for all materials
Insertion pit required
Reduces pipe diameter
Not well suited for small diameter pipes
Bypass or diversion of flow required
Curing can be difficult for long pipe segments
Must allow adequate curing time
Defective installation may be difficult to rectify
Resin may clump together on bottom of pipe
Reduces pipe diameter
Bypass or diversion of flow required
The cross section may shrink or unfold after expansion
Reduces pipe diameter
Infiltration may occur between liner and host pipe unless sealed
Liner may not provide adequate structural support
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groundwater redirection will offset the decrease in
pipe diameter and meet project objectives for an
increase in peak flow and/or reduction in SSOs.
Most trenchless rehabilitation applications require
laterals to be shut down for a 24 hour period.
Coordinating shut-downs with property owners can
be a difficult and unpopular task. Unforseen
conditions can increase construction time and
increase the risk and responsibility to the client and
contractor. For example, during a rehabilitation
proj ect in Norfolk, Virginia, pipe bursting had to be
coordinated with the relocation of a nearby
electrical substation and the rerouting of flow from
a sanitary force main found in a manhole where an
insertion pit was to be located (Small, Gidley, and
Riley, 1997). In addition to these issues, numerous
abandoned underground utilities which were not
indicated on city or private utility records were
encountered during the project. Such underground
conditions are found in many other urban
environments around the United States. When
trenchless rehabilitation is planned, public works
projects and utility work by other agencies should
be coordinated with sewer rehabilitation projects.
PERFORMANCE
The performance of trenchless techniques in
reducing I/I can be determined through flow
measurements taken before and after the
rehabilitation. Effectiveness is typically calculated
by correlating flow measurements with
precipitation data to determine the peak rate and
volume of I/I entering the collection system.
Another method of calculating I/I is to isolate the
rehabilitated line and measure flows both before
and after the rehabilitation.
The performance of sewer rehabilitation projects in
three Northeastern Illinois communities was
documented by Goumas (1995). Results of pre-
and post-monitoring within these three
communities indicate that I/I reductions of 49
percent, 65 percent and 82 percent were achieved.
The Washington Suburban Sanitary Commission
(WSSC) uses the isolation and measurement
method to assess the performance of rehabilitation
projects. An analysis of 98 sewer mains
rehabilitated between 1989 and 1995 indicates that
I/I flow was reduced by 70 percent in the
rehabilitated sewers (WSSC, 1998).
The Miami-Bade Water and Sewer Department
(MDWASD) is completing one of the country's
largest I/I reduction programs. The program, aimed
at reducing I/I thoughout the system, utilizes the
fold and form, CIPP, pipe bursting, and sliplining
rehabilitation techniques in conjunction with point
and robotic repairs. MDWASD has already
experienced success with this program; an average
I/I reduction of 19 percent (20 MGD) has been
achieved between January 1995 and May 1998
based on comparing plant flow and billed flow
(MDWASD, 1998)
In Fairfax County, VA, between June 1994 and
June 1998, wet weather flows were significantly
reduced within the two sewer sheds identified in the
County's focused rehabilitation program even
though the program addresses only main and trunk
sewer lines and does not address I/I from private
laterals (Fairfax County, 1998).
These studies should only be used as an indicator of
potential I/I removal. Removal rates will vary
depending on the material and condition of the pipe,
local soil type, groundwater flow, and other site-
specific conditions.
COSTS
Cost ranges for trenchless rehabilitation of a typical
size sewer main are provided in Table 3. These
costs include a standard cleaning of the sewer line
(major blockages and point repairs increase the
cost) and inspection of the sewer line before and
after the sewer is rehabilitated. Sewer rehabilitation
by both trenchless and traditional dig- and-replace
methods can reduce treatment and O&M costs at
the receiving treatment plant by potentially
eliminating I/I flows to the plant. In addition to
treatment cost savings, energy costs for transporting
flows to the treatment plant could also be reduced
due to the reduced flow volume.
A cost comparison of trenchless and traditional
sewer rehabilitation methods must consider the
condition and site characteristics of the existing
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TABLE 3 TYPICAL COST RANGE FOR SMALL SEWER MAINS
Technique
Pipe Diameter, mm (in.)
Cost Range, per linear meter (ft.)
Pipe Bursting
Sliplining
CIPP
Modified Cross Section
203 (8)
457(21)
203 (8)
203 (8)
$130-$260 ($40-$80)
$260-$550($80-$170)
$80-$215($25-$65)
$58-$162($18-$50)
Sources: Kung'u (1998), Burkhard (1998), Cost in 1998 dollars.
These costs are an indicator of some project costs but each project cost is site-specific.
pipeline. Factors influencing the cost of a
trenchless sewer rehabilitation project include:
• the diameter of the pipe;
• the amount of pipe to be rehabilitated;
• specific defects in the pipe (such as joint
offsets, root intrusions, severe cracking or
other defects);
• the depth of the pipe to be replaced, and
changes in grade over the pipe length;
• the locations of access manholes;
• the number of additional access points that
need to be excavated;
• the location of other utilities that have to be
avoided during construction;
• provisions for flow by-pass;
• the number of service connections that need
to be reinstated; and
• the number of directional changes at access
manholes.
In general, the less the amount of excavation
required for a rehabilitation operation, the more
cost-effective trenchless sewer rehabilitation
becomes as compared with the traditional dig-and-
replace method. In addition to excavation and
installation costs, sewer cleaning and inspection are
typically required before sewer rehabilitation
REFERENCES
1. Fairfax County Department of Public
Works, Burke, Virginia, 1998. I. Khan,
Director of Line Maintenance Division,
personal communication with Parsons
Engineering Science, Inc.
2. Goumas, J., 1995. "Tri-Villages of Greater
Chicago Reduce I/I with CIPP," Trenchless
Technology 4(3): 70-71.
3. Iseley, T. and M. Najafi, 1995. Trenchless
Pipeline Rehabilitation. Prepared for the
National Utility Contractors Association,
Arlington, VA.
4. Kramer, S. R. And J. C. Thomson, 1997.
"Trenchless Technology in the Year 2000
and Beyond." In Trenchless Pipeline
Projects: Practical Applications, ed. Lynn
E. Osborn, pp. 174-182. New York: ASCE.
5. Kung'u, Francis, 1998. Excavation and
Elimination: No-Dig Solutions to Sewer
Problems, Civil Engineering News 10 (7):
45-49.
6. Kutz, G.E. Predicting I/I Reduction for
Planning Sewer Rehabilitation, 1997. In
Trenchless Pipeline Projects: Practical
Applications., ed. Lynn E. Osborn, pp. 103-
110. New York: ASCE.
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7. Miami-Bade Water and Sewer Department,
(MDWASD) Coral Gables, FL, 1998. L.
Aguiar, Assistant Director, personal
communication with Parsons Engineering
Science, Inc.
8. Pipeline Rehabilitation Council, 1998. M.
Burkhard, president, personal
communication with Parsons Engineering
Science, Inc
9. Saccogna, Laura L., 1998. Swagelining
Renews Force Main Under the Elbe River,
Trenchless Technology International 2(1):
28-29.
Missouri Western State College
Mohammad Najafi, Ph.D., P.E.
Department of Engineering Technology
St. Joseph, MO 64507
The mention of trade names or commercial
products does not constitute endorsement or
recommendation for use by the U. S. Environmental
Protection Agency.
10. Small, A.B., J.S. Gidley, and D.A. Riley,
1997. "Design and Rehabilitation of an
Urban Gravity Interceptor Using
Pipebursting in Norfolk, Virginia,"
Trenchless Pipeline Projects: Practical
Applications., ed. Lynn E. Osborn, pp. 174-
182. New York: ASCE.
11. Washington Suburban Sanitary
Commission, Laurel, MD, 1998. A.
Fitzsimmons, Washington Suburban
Sanitary Commission, personal
communication with Parsons Engineering
Science, Inc.
ADDITIONAL INFORMATION
Fairfax County, Virginia
Ifty Khan, Director -Line Maintenance Division
Fairfax County Department of Public Works
6000 Freds Oak Road
Burke, VA 22015
Louisiana Tech University
Raymond L. Sterling, Ph.D., P.E.
Trenchless Technology Center
West Arizona Avenue
P.O. Box 10348
Ruston, LA 71272-0046
Miami-Dade Water and Sewer Department
Luis Aquiar, Assistant Director
4200 Salzedo St.
Coral Gables, FL 33146
For more information contact:
Municipal Technology Branch
U.S. EPA
Mail Code 4204
401 M St., S.W.
Washington, D.C., 20460
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Excellence in compliance through optfmal technical solutions
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