For employees of the TRILITY Group and Joint Ventures
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Emergency reinstatement of essential services to
Rotorua residents
Just before Easter, our Rotorua team in conjunction with Rotorua Lakes
Council and network partner Fulton Hogan worked in collaboration to
reinstate vital services. Their work continued through and post-Easter to
remedy the consequences of a failed major gravity main that had affected
one of the 90 pump stations TRILITY operate and maintain across Rotorua.
The TRILITY team, Council and Fulton Hogan worked tirelessly to access
and undertake the works to reinstate the collapsed sewer main.
The Hona Road pump station pumps failed due to blocking because of the
collapse in the gravity main entering the station. The Tomo that was formed
approximately six metres upstream of the wet well was significant enough to
dump greater than 15 cubic metres of material such as pumice, rubble, house
bricks and bitumen as shown in the images below. The well level experienced
an instantaneous two metre rise due to the displacement of water caused by
the Tomo material. This material immediately incapacitated both the duty
and standby pumps rendering the pump station inoperable until the material
and the pump wet well risers were cleared of debris.
The situation was deemed a high priority emergency works; residents were
asked to minimize water use to assist with remediation. Reinstatement of
the pump station proved to be challenging; multiple specialist crews were
engaged to undertake work on the pump station. It required the mobilsation
of a significant amount of plant, people and other resources including trucks,
four large diesel pumps for pumping over the wet well, divers, fencing and
floodlights etc. on-site. The remediation works were conducted over several
attempts at night because this is when flows into the pump station were at
their lowest and sucker trucks could easily move through the roads to access
the disposal site to dump the recovered material.
Tim Overland, Commercial Manager Operations
toverland@trility.com.au
Main collapse of Tomo forming
Represenation of material removed from pump station wet well
Throughout the reinstatement an overflow of the pump station was
completely avoided, this was an excellent result given the proximity of the
pump station to Lake Rotorua.
The reinstatement was successful due to the combined efforts of all involved;
with the restoration of the pumps in the pump well and return to normal
operations being achieved within 11 days.
Removing manhole top
Pipe relined