Treatment process pipe repairs see increase in truck movements

The Team from Wellington Water

It never rains but it pours – another tricky pipe repair job for our team!

Running between the wastewater treatment plant at Moa Point and the Southern landfill are two pipes that carry a treatment process byproduct, generally known as sludge.

Only one pipe operates at a time, to allow for maintenance, but over the weekend, both pipes suffered damage that meant we couldn’t keep using them.

They’re under very high pressure when they’re operating, so it’s possible that the live pipe disrupted the other one when it failed.

The pipes were expected to last for a good 80 years or more, so we think that some kind of installation or material defect has caused them to stop working.

En route from the treatment plant to the landfill, the pipes pass through a tunnel beneath Mt Albert, and this is where the repair will be carried out.

While we carry out the repairs, trucks will be used to convey sludge from the plant to the landfill. About a million litres of sludge a day is generated at the plant, and trucks may need to operate around the clock from time to time.

A similar repair, also due to a defect in the concrete in which the pipes are embedded, was carried out in 2013 and took about five weeks to complete.

We’ll provide more information on the repair timeline and truck schedule as we learn more.