Sewer Rehabilitation – Lidcombe & Silverwater

Project Summary Sheet

Customer: Sydney Water

Location: Lidcombe & Silverwater, NSW

Delivered: September 2012

The Challenge

This project called for the structural lining of 1.2 kilometres of DN900 sewer that passed under one of Sydney’s busiest intersections. Depths ranged from 13 to 22 metres, distances between access points were up to 200 metres and there was one significant mid-length bend.

The work had to be completed without service interruption by a work method that allowed restoration of full flow capacity within three hours.

The Solution

Further development of SPR™ EX – Expanda Pipe and SPR™ RO – Rotaloc spiral wound liners was needed to complete this project.

Civil works included multi-level pit construction for bypassing dry weather flow from a sewer too deep to allow sewage to be pumped to the surface in one lift.

The Project

Project restrictions meant that spiral wound liners were the only practical solution principally as they allowed the possibility of rapid restoration of sewer flow capacity in emergencies.

The project was completed using grouted SPR™ EX – Expanda Pipe and SPR™ RO – Rotaloc liners, but required the following innovation and development:

  • A stronger SPR™ EX – Expanda Pipe profile and upgraded installation equipment providing a liner with the stiffness to meet design requirements.
  • SPR™ RO – Rotaloc “bend profile” to install the SPR™ RO – Rotaloc liner continuously through the mid-point bend.
  • A cementitious grout composition that flowed long distances without shrinkage or separation.
  • The distances between maintenance holes were too long for continuous full length liner installation. A work process was developed to install SPR™ EX – Expanda Pipe liners from both directions joining them with a structural fibreglass patch.
  • Construction of a “pump out pit”, with cast piles and shotcrete walls over reinforcing mesh for the bypass pipework.


Interflow’s culture of innovation allowed this project to be successfully completed. The developments on this project have extended the possibilities for structural rehabilitation of deteriorated sewers into areas previously considered too difficult or impossible.

This project was a winner of an International Society for Trenchless Technology “No Dig” Annual Award as the most impressive project world-wide in that year.

Interflow is committed to offering its customers customised solutions of the highest value for pipeline rehabilitation.