Treatment process pipe repairs see increase in truck movements
Investigations are under way for repairs to two pipes that convey a wastewater treatment byproduct – generally known as sludge – from Moa Point Treatment Plant to the council’s Southern Landfill in Carey’s Gully.
The pipes were installed in the mid-1990s, when the treatment plant was built (prior to that, wastewater was discharged to the sea at Moa Point via a short outfall pipe). They were designed to last for 80 years or more, and we believe these repairs are the result of an installation defect.
Only one pipe is operating at a time, but in this case, repairs are necessary on both. The pipes are under very high pressure when operating, and pass through a tunnel beneath Mt Albert. 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.