WC146 JanFeb 2026 - Magazine - Page 19
City of Calgary
treatment prior to its release back into the
Bow. Crews also used ground anchors to
secure all concrete tanks deep and solidly
into the bedrock.
Moving the existing outfall 900 metres
downriver during Phase 1 also proved
challenging. “We had to build under Deerfoot Trail and open-cut CN Rail tracks to
place our pipes underneath, and we had a
tight deadline to get it done,” Jablonski
says. As well, the outfall was placed close
to the now-closed St. Dunstan’s residential
school. “We had to bring in palaeontologists, archaeologists and historical researchers, and completed excavation and mapping of the school’s foundation prior to
construction. We also encountered unexploded ordnance—cannonballs—in the
soil along the river bank, so we had to use
bomb-proof excavators.”
There were also site constraints, which
the project team addressed in different
ways. Lacking sufficient space to manoeuvre one tower crane, crews integrated its
base into the base slab that would later be
used to help anchor the tanks. “Once the
tower crane is removed, it became the base
for our bioreactor,” Jablonski explains.
“Usually you install your tower crane next
to your construction site to lift things in
and out, but we integrated both pieces
into one inside because we couldn’t physiThe City expresses con昀椀dence that the addition of Plant D will enable Bonnybrook to adequately serve its
cally locate it next to it.”
catchment area for the immediate future.
The dearth of space was itself apparent
throughout the construction of Plant D.
Planners used the very last bit of available
into a live, operating wastewater plant because you can’t shut it
land at the Bonnybrook site for the expansion, so any further expandown,” Jablonski explains, noting careful attention to sequencsion will likely necessitate going beyond the site’s current boundaing events and procedures in the correct order. Upgrading
ries. Jablonski expresses confidence that the addition of Plant D will
existing anaerobic digesters, undertaken at the very start of
enable Bonnybrook to adequately serve its catchment area for the
Phase 1, proved a case in point. Crews could only take one
immediate future, but she acknowledges that ongoing population
digester offline at a time to work on it, which lengthened the
growth could eventually place further demands on the system. To
process somewhat.
that end, she says, City Council has approved an application to
Potential impacts from the site’s immediate proximity to the
rezone a section of land across the street for a future Plant E.
Bow River and a correspondingly high groundwater table also
For now, though, as work on Plant D winds down, Jablonski
required constant consideration. “If we dig one metre down
says the site trailer will soon be removed even as crews complete
our excavation is inundated,” Jablonski says. “But to build
the berm’s extension and final touches on equipment such as the
these concrete tanks it needs to be bone dry, so a lot of effort
anaerobic digesters as well as landscaping and civil works. “We
went into the design and construction up-front.” Crews built
might have another year and a half until everything is 100 per cent
secant walls and dewatering wells to keep the ground parched,
buttoned up and our contractors have left, but otherwise
and directed all excess waters into the treatment plant itself for
everything is operating brilliantly.”
WAT E R C A N A D A . N E T
WATER C AN ADA • JANUARY/ FEBRUARY 2026
19
