Innovative Technology Used To Replace Sewer Pipes
Contractors have this week started work on relining sewer mains in Rotorua’s Whakatau area using an innovative process
called inversion which involves manufacturing new pipes within old pipes using polyester resin.
The $1.03 million wasterwater pipe renewal project which puts a flexible resin liner inside existing pipes, should be
completed by next month.
Because of the process used it should have very little impact on residents, said Rotorua Lakes Council contract
supervisor Geoff Kitson.
The method used extends the life of underground sewer and drainage structures without digging up people’s lawns or with
any lengthy interruptions.
PipeWorks, a Fletcher Construction Company subsidiary, has used the Cured-in-Place Pipe Liner technology throughout New
Zealand in both small and large diameter sewer lines, stormwater drains, circular and egg shape pipes.
Much of their work in recent times has been in Christchurch post the 2012 earthquake.
Initial work in Rotorua involved putting a camera into the pipes to check their structural condition and to identify any
impediments such as tree roots, broken pipes and rotten rodents.
It was important to get those impediments out of the way, clean the pipes and make minor repairs before starting the
renewal process, said Kitson.
“The primary work, which started this week in Whakatau St, involved putting a flexible resin liner inside the existing
pipe. Once the liner is inside the pipe, it will be cured with steam to form a new pipe against the existing pipe.”
Contractors will monitor the temperature during that crucial period to ensure it stays at around 60 degrees celcius.
Kitson said it was important to minimise the disturbance to residents so work is being done between 7am and 7pm using
construction equipment such as air compressors, generators, boilers and diesel engines.
Some parts of footpaths and roads are also penned off while the work is done.
The polyester resin emits some smell, said Kitson.
Letters have been delivered to all businesses and residents in the area detailing the work plan.
Watch a video showing the process.
ENDS