constructed to essentially entomb waste
that was buried at the site and prevent it –
along with impacted groundwater – from
migrating into the surrounding environ-ment.
Waste at the surface and at shallow
depths was removed and disposed of at a
licenced landfill prior to construction of
the containment cell.
“A major advantage of the Waterloo
Barrier® is that excavation of subsurface
materials is not required, thus there is
less damage to the site and disruption
of normal site activities,” Le said, adding
that the high costs associated with the
health and safety precautions that are
required to excavate and dispose of con-taminated
material were also avoided.
Watertight system
The Waterloo Barrier® is comprised of
interlocking steel piles that incorporate
a unique sealable joint system which
makes the system virtually watertight –
an essential consideration for the 5 Wing
Goose Bay project.
According to Le, conventional steel
sheet piling is seldom used in envi-ronmental
applications due to an
unacceptable amount of leakage through
the interlocking joints.
In the Waterloo Barrier® System, the
interlocking joints incorporate a cavity
that’s created by cold roll forming in the
sheet pile manufacturing process. Le
explains that a footplate at the bottom of
each cavity displaces soil laterally as the
sheets are driven into the ground, allow-ing
the joints to remain largely soil free.
“Soil that does enter the joints is
relatively loose and easily removed by
jetting with water,” he said, adding that
epoxy, cement or clay-based grout is
then injected into the sealable cavities
between the sheet piles to create a low
permeability barrier.
Le notes that the Waterloo Barrier® is
the only system where the joint sealant
is placed after the sheet piling has been
driven and is in the ground.
Le says a number of different water-tight
sealants particularly resistant to
chemical degradation are used in the
process and that because the volume
of required sealant is relatively small,
they’re economical to use.
For the 5 Wing Goose Bay project,
C3 Environmental was contracted by
Quebec firm Loiselle Environment to
GREAT CANADIAN PROJECTS
The Waterloo Barrier® System was initially developed by a team of researchers
at Ontario’s University of Waterloo in the late 1980s. In 1992, the system
was commercialized and since then it’s been used in more than a hundred
projects in Canada and the United States, according to Minh Le, president of
C3 Environmental Limited.
“Most of these projects are high-profile projects that require extremely low
permeable containment systems or cutoff walls,” Le said. “The Waterloo
Barrier® is also industry standard or the ‘go-to’ technology when comes to
environmental containment or cutoff walls for impacted groundwater.”
Le says the biggest project that’s utilized the Waterloo Barrier® System was
the Randle Reef Remediation Project in Hamilton, Ont. This $139-million
initiative involved the construction of a 6.2-hectare island in Hamilton’s
harbour on Lake Ontario that included the use of Waterloo Barrier® sheet piles
to help contain nearly 700 million cubic metres of contaminated sediment
dredged from the lake bottom.
Other remediation projects utilizing the Waterloo Barrier® System include:
• Northern Wood Preservers Sediment Remediation, Thunder
Bay, Ont. – Implemented in a containment system for creosote
contaminated sediment.
• Former Kitchener Landfill, Kitchener, Ont. – Implemented for cutoff walls
to prevent the migration of methane gas into residential areas.
• Former Venus Mine, Carcross, Yukon – Implemented for cutoff wall to
prevent migration of arsenic contaminant into an adjacent lake.
• Atomic Energy Canada Limited, Chalk River, Ont. – Implemented for
cutoff wall to prevent migration of radioactive contaminant into an
adjacent area.
• Bay Shore Former Manufactured Gas Plant, Bay Shore, N.Y. – Implemented
for cutoff wall to prevent migration of solvents and hydrocarbon into a
residential area.
• Housatonic River Remediation, Pittsfield, Mass. – Implemented for cutoff
wall to prevent migration of hydrocarbons into an adjacent river.
• Beaverbrook Art Gallery Expansion, Saint John, N.B. – Implemented for
waterproofing system to protect the new addition to the art gallery.
PILING CANADA 41