Australian Water Management Review Vol. 1 2014 | Page 130

Oviform Sewer
Rehabilitation in the West
Kembla Watertech field crews have just
successfully completed a challenging
contract in Western Australia. The Mount
Lawley (East Perth) main sewer was
scheduled for refurbishment, as well
as a main sewer in Fremantle. Kembla
Watertech relined these oviform sewers
with UV cured CIPP lining installations. A
major part of this contract was managing
the sewer flows, and installing a partially
unground bypass system in East Perth.
Additionally, oviform patching was a
major part of this contract.
Patching in reticulation lines has been a day to day
task at Kembla Watertech. However, field crews had
to become oviform patching experts prior to starting
patching work on this contract. Kembla Watertech
Project Manager, Paul Propper explains, “Kembla
Watertech was awarded a contract relining oviform
sewer mains in Perth, Western Australia, and due to
a sudden pipe collapse from deteriorated pipe before
lining rehabilitation, oviform patching was required.” He
continues, “Our staff successfully installed 28 oviform
patches battling extreme temperatures and high UV
index over two months in Perth and Fremantle.”
To become experts in oviform patching, the team began
an extensive period of research, where theory and existing
case studies were examined. However, it soon became

Figure 1: Above ground testing facility in Perth

124 | Australian water man age m e nt re v ie w

evident that information regarding oviform patching was
scarce, so practical testing of physical conditions would
be necessary. The team designed above ground testing
areas at our depot in Sydney, and on site in Perth to
ensure the team had a real sense of how the conditions
would impact them and began a process of trial and error
to work out an efficient and successful system. A training
program was then undertaken for other crew members to
become proficient in the patching system.
A major part of this contract was flow management.
Kembla Watertech worked closely with subcontractors
to develop an appropriate flow management process for
this project, which involved nearly a kilometre of bypass
hose in three sections, one of which was a 400 metre
underground buried bypass hose to assist with road
crossings. Kembla Watertech Project Manager, Paul
Propper explains, “The underground bypass hose helped
reduce the impact on local roadways, traffic and helped
alleviate public safety concerns in a residential area.”

a battle to install the patches prior to the resin curing.
Shade structures were implemented to reduce the direct
sunlight on both the resin and on the workers. Patches
were installed early on in the shift and later on in the early
evening to try to reduce the risk of curing the resin in the
middle and hottest part of the day.
This contract also involved installing UV cured oviform
liners into 380mm x 255mm oviform sewer lines in
Fremantle and East Perth. Ancillary work involved bypass
coordination, removing manhole benching, lids, and
step irons in order to facilitate lining equipment. Bypass
installation was a huge component with a 70m bypass
hose buried underground with four road crossings to
prevent a major traffic control set up and to reduce public
safety concerns.
The project was finished in February 2014, with many
customers commenting on the professional nature of the
workers, and attentiveness of staff when liaising about
project impacts.

Kembla Watertech Managing Director, Chris
Meredith, is pleased with the expertise gained by the
crews and said, “The project management and field
crew worked together well to complete this project
seamlessly considering the challenges faced including
working with a new client, management of multiple
subcontractors, extreme temperatures, and having to
gain expertise in oviform patching.”
The physical conditions were quite extreme and with
temperatures pushing 40 degrees on most days it became

Figure 2: Finished product

Figure 3: Above ground trial