Sewer Pipe Money Saver

2 August 2010

A smart, no-dig technique has given new life to the sewer pipe running beneath the southern runway approach to Wellington Airport, and has saved almost a million dollars.

Checking the PVC lining wound into the outer pipe

Checking the PVC lining wound into the outer pipe

The large (1.35 metre) sewer pipes were seriously corroded, and full replacement would have been expensive and difficult, since the airport is in constant use. So engineers turned to a no-dig technique that provides an acid resistant, stand-alone lining that sits within the sewer pipe.

The lining is narrow PVC that's wound into the pipe by an automated crawler. This glues and snaps the strip into a continuous spiral as it goes. Once the lining is cured, it is independent from the sewer pipe - forming a pipe within the original pipe.

The work, managed by the Council's infrastructure services company Capacity, is estimated to have saved the city $989,000 over alternative replacement options.