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Truckloads of sludge continuing 24 hours every day, till broken sewage pipes are fixed

News from Wellington Water
Trucks continue their operations 24/7, transporting sludge from the Moa Point treatment plant to the southern landfill. The drivers have been greeted with a positive response from the community.

We have begun CCTV through the Mt Albert tunnel, which is an essential part to our investigations, helping us to understand the extent of the fault and look into solutions for the long term repair.

News from Wellington Water – January 27
Trucks continue to work around the clock, transporting sludge from Moa Point to the landfill. We have managed to reduce the number of trucks and still continue to keep up with demand, meaning we are avoiding discharge into the Cook Strait.

We understand truck movements may be inconvenient to residents along the route, and we thank them for their understanding. We are briefing truck drivers to ensure they are keeping themselves and the public safe by reducing their speed.

Wellington.Scoop – January 24
The collapse of another Wellington Water sewage pipe – this one on Wellington’s south coast – means trucks will be hauling millions of litres of sludge every day from the Moa Point treatment plant to the southern landfill. There will be up to 150 round trips every day, for at least four weeks. The emergency is expected to cost ratepayers $200,000 each week.

The latest failure, which happened last week, occurred in the Mt Albert sewer tunnel – part of a 9km pipeline that links the treatment plant with the Southern Landfill.

Trucking sludge is an attempt to prevent wastewater having to be discharged into Cook Strait, but Wellington Water has warned a repair could be more than a month away. RNZ quotes Wellington Water chief wastewater advisor Steve Hutchison as saying:

“The complications are that the pipes that need repair are encased in concrete in the base of the sewer tunnel… so we have to arrange for that flow to be bypassed.” Hutchison emphasised this would be a temporary fix – work was underway to plan a repair with a temporary bypass, as well as a long-term fix.

He said they may need to operate around the clock at times to keep up with the volume – about a million litres each day.

While there was some heightened risk of infection with sewage being moved above grounds, hygiene was being handled carefully among truck drivers, and all trucks would be closed.

News from Wellington Water
The operation was today refined by reducing the amount of trucks on the road and splitting them into two shifts of 6-7 trucks each. These trucks are continuing to keep up with demand, and are operating efficiently.

The fault in the pipeline was located yesterday, and we are continuing to plan a repair with a temporary bypass, as well as a long term fix. The location appears to be about 200m inside the tunnel under Mt Albert.

We are working with the local community at Moa Point, and are holding a community meeting on Sunday to update them on the project and address any concerns.

News from Wellington Water – January 23
Trucking operations are continuing as an alternative to the sludge pipeline between Moa Point Treatment Plant and the landfill at Carey’s Gully.

The pipeline failed last week, and a repair could be a month away or longer. No wastewater or sludge was discharged to the environment as a result of the failure, which occurred in a wastewater tunnel beneath Mt Albert.

Investigations have located the point of failure and work is under way to plan a repair with a temporary bypass, as well as a long term fix. It will be a complex job, because wastewater also flows through the tunnel towards Moa Point, making for dangerous working conditions.

With the pipeline out of action, there is a risk that if the trucking option is interrupted for 24 hours or more, some sludge may need to be discharged via the long outfall pipe that carries treated wastewater out to Cook Strait.

When the plant was built, the intended alternative to pumping sludge to the landfill in the event of a significant failure was to discharge it via the long outfall. Public expectations have changed since then however, and Wellington Water and teams of contractors are making every effort for this not to happen.

The trucking system is keeping up with daily demand, but because treatment operations at the plant and the landfill were not designed to load and unload sludge from trucks, there remains a risk that we may have to discharge sludge from the outfall.

Wellington Water is also working across a number of other options for the pipeline repair and to manage the sludge volumes.

The treatment plant discharges over 70 million litres of treated water a day.
Just over a million litres of sludge is produced at the plant a day. This is being transported by truck to the landfill.
The sludge pipeline from the treatment plant to the landfill runs for 9km. It consists of two pipes, which operate one at a time, to allow for maintenance. It is highly unusual that they both have failed.

News from Wellington Water – January 22
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 city 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.

5 comments:

  1. Wellington Commuter, 23. January 2020, 15:57

    The very definition of a shit job … [from twitter]

     
  2. Bald Rick, 23. January 2020, 16:07

    ‘Night soil’ removers were well paid back in the Middle Ages. In London, they ended their day with a dip in the Thames. Wellington’s equivalents might find the harbour too cold and too dirty to do the same.

     
  3. Codger, 24. January 2020, 17:27

    Yes, in those happy days the Thames was not nearly as cold or dirty as it is now.

     
  4. Brooklyn Residents Assn, 24. January 2020, 18:36

    Approximately 70/80 trips (140/160 there and back) vehicle trips daily for a month or more along the south coast/southern suburbs … So if you are out and about walking or driving along the south coast and a strong smell of sewage is around, this is likely the reason.

     
  5. Jamie, 25. January 2020, 6:47

    Wellington you tip 70million litres of treated wastewater into Cook Strait every day. Provincial towns and cities don’t have this luxury we have to invest in high-priced discharge-to-land wastewater systems rather than using the river because it is culturally insensitive. Time you woke up and realised everytime you flush it goes into the sea, with sludge removed and some treatment.