Te Whare Wai Para Nuku
Moa Point sludge minimisation facility

About the project

Sludge is the name for the solids created through the wastewater treatment process. It is not an easy, or nice, material to dispose of. At the moment it’s piped 9km across Wellington to the Southern Landfill, where some of its water content is taken out. What’s left is buried in the landfill – our current consent means we have to mix one part sludge with four parts general waste.

We’re building a facility that will change all that. Te Whare Wai Para Nuku will reduce the volume of sludge created by up to 80 percent by creating a stable, dry, odourless product that can be more easily transported, and used in productive ways such as a soil conditioner and fuel for industrial heat.

The facility will make it easier for us to meet our goals in our Te Atakura: First to Zero and He anamata pare kore mō Pōneke: A zero waste future for Wellington.

But that’s not all:

• The facility will reduce emissions created through the treatment and processing of sludge by up to 60 percent.
• The sludge will help power all this treatment – as it breaks down it will produce a biogas that is captured and used to create heat and electricity to help run the process.
• What we’re building aligns with mana whenua values, such as the principles of rahui in disposing of human waste, harnessing the resources in sewage sludge to give them another life, and kaitiakitanga – having a positive impact on the environment and our communities through the action we take.
• The facility uses a process that includes hydrolysis, anaerobic digestion, dewatering and thermal drying.

How the process works

The heart of Te Whare Wai Para Nuku is the anaerobic digestion process, which mimics the natural decomposition process of waste, breaking down biodegradable matter in the sludge. As the sludge breaks down, it produces biogas which is captured and used to produce heat and electricity, which helps run the process.

To make the anaerobic digestion process even more efficient and harness more energy from the sludge as it breaks down, the sludge is first put through thermal hydrolysis. This acts like a pressure cooker on the sludge, breaking down the sludge molecules so that the sludge becomes easier to digest in the anaerobic digesters. It also makes the sludge easier to dry.

Because the product is inert, it can be easily stored or transported to other locations for disposal or potentially used productively for other purposes.

Benefits for Wellington

This new facility will have positive impacts for our city:

• Environmental impact: Significantly reduces waste and carbon emissions, contributing to a greener, healthier city.
• Long-term cost savings: Efficient waste processing will potentially reduce future waste management costs.
• Community health: Cleaner waterways and a reduced carbon footprint contribute to better public health.
• Compliance: Helps the Council meet local and national waste minimisation standards.

Sludge minimisation facility levy

In August 2024, we introduced a levy to all ratepayers.

This levy is to cover the approximately $400 million required for this new facility without affecting Council funding for other important infrastructure and community projects. The levy will be collected for a period of 33 years commencing 1 July 2024.

Find out more about the sludge minimisation facility levy.

Project milestones

October 2020: Wellington City Council was presented with a preferred option for a sludge minimisation facility. In reaching the preferred option, Wellington Water considered a range of viable options for the new plant, to be located at either Carey's Gully at the Southern Landfill, or at Moa Point. They then worked with representatives from Wellington City Council, mana whenua, and local and international technical experts to identify a preferred option.

Late 2020: Wellington City Council began actively engaging with the local community about the project.

June 2021: We consulted on the project and the use of the Infrastructure Funding and Finance Act 2020 (IFFA) to finance it through the Long-term Plan process.

April 2022: We again sought ratepayer feedback on the use of the IFFA to finance the development of the new facility.

June 2022: Business case approved.

August 2022: The Council considered options for an IFFA levy proposal to fund the facility, including levy design options, ahead of a potential decision to submit a levy proposal in December.

Mid-August to late-September 2022: Submissions open on the Notice of Requirement for an alteration to Designation 58 (WCC6 under Proposed District Plan) for the construction, operation, and maintenance of a new Sludge Minimisation Facility (SMF) at 127 and 141 Stewart Duff Drive.

December 2022: Construction approved.

May 2023: Works begin on site for the construction of the facility.

November 2023: Hillock removed.

November 2023: Piling works began.

November 2023: The Outline Plan of works approved with no requests for change.

Mid-2024: Commencement of levy payments via rates bills as a separate line item.

September 2025: Main process building external cladding and roof complete.

Late-2026: Facility expected to be operational.

Updates

Read the latest news and updates and follow the progress of the construction through images and video.

Contact us

If you have queries or concerns about the day-to-day construction work at the site, call our construction team.
Phone: 0800 796 525.