Ruakākā Wastewater Treatment Plant upgrade
- Project typeWastewater treatment plant upgrade
- Project schedule2025 to 2030
Bream Bay (including One Tree Point, Marsden, Ruakākā and Waipū) is an area of high growth identified in the Whangārei District Growth Strategy and the Future Development Strategy (see below).
There are currently two wastewater treatment plants servicing the area – one in Ruakākā and one in Waipū.
We are undertaking significant upgrades to the wastewater system in Ruakākā, which include:
- a treatment plant upgrade; and
- a new treated wastewater discharge facility via ocean outfall, or
- an alternative discharge method for treated wastewater.
In addition, we are undertaking an interim additional discharge facility, which will address capacity limitations faced by the existing treatment plant.
This project opens up opportunities for beneficial reuse of the treated wastewater and the biosolids in the future, as well as reducing any risk of contamination in the environment.
Download the following document to learn more about wastewater treatment and the project:
Ruakākā Wastewater Treatment Plant expansion project: Knowledge builder(PDF, 16MB)
New wastewater treatment plant
Preliminary design of the new treatment plant is complete with detailed site evaluations now complete. The preferred treatment method is known as multistage biological nutrient removal with membrane tanks. This will meet the consent requirement for a very high quality of treated wastewater discharge with the membrane removing all pathogens.
The proposed site for the new treatment plant is on part of the Rama Road block site, currently owned by Whangarei District Council. This avoids additional land costs and makes it easier to designate for wastewater treatment and disposal purposes. However, it will require new regional resource and building consents.
Procurement for detailed design is underway with construction scheduled to start in 2027 and completion due in 2030.
Land contact
Following discussions with Patuharakeke Te Iwi Trust Board, the mauri (life force) of the water will be restored through a nature-based land-contact bed before disposal to any of the discharge options.
Land contact ensures that the treated wastewater being returned to the environment is culturally aligned to that environment and the mauri of the water has been restored.
The land contact process requires the water to pass through the earth before again joining the light and returning to the environment. Locally sourced materials will be used in the system.
Biosolids management
The current pond system at Ruakākā requires periodic desludging of sludge from the pond and, when this has dried, it is taken to landfill for disposal. The new treatment plant opens up the opportunity for a more sustainable option.
The current preferred option for the management of biosolids (the waste sludge remaining after treatment of the wastewater) are sludge treatment reed beds (STRB). In this nature-based process, treatment bacteria break down the biosolids removing organic material and pathogens over a period of eight to 10 years. Plants enhance the soil-like nature of the biosolids, remove water and produce a higher quality product with very low risk of odour. This end-material can be suitable for many uses, including horticulture, forestry and land remediation in the future.
Sludge treatment reed bed. Thanks to Orbicon / WSP for providing this diagram.
The reed beds will likely be located on the site of the new treatment plant.
A trial for this innovative sludge-treatment methodology (used extensively in other countries) will start in February 2026 at the Whangārei wastewater treatment plant site to inform the right native New Zealand plants and operating conditions for Northland.
Disposal options
As well as constructing a new wastewater treatment plant, investigations are underway to explore options for how we manage the treated water. These include discharge via ocean outfall and alternative discharge methods including to land, harbour or river.
Land disposal, although favoured by many in the community, has been shown to be impractical, as there is insufficient suitable land in the rohe.
A key focus when evaluating these discharge options is the required water quality, particularly microbial standards, to ensure minimal effect on the local environment and kai. While a number of investigations have already been conducted, a further study is being undertaken to confirm that the high level of disinfection by physical membrane barrier and UV is sufficient to keep shellfish safe in the area.
To consider the viable options identified, we are building an understanding of environmental effects, treatment standards, cultural impacts and costs to the community (both to build and to operate), which will be shared with Council and community in the near future.
Discharge to ocean outfall
The existing resource consent authorises the discharge of highly treated wastewater into the ocean at Bream Bay via a 3km pipeline.
The current consent conditions, which authorise the discharge of treated wastewater into the ocean, are much stricter and broader than the recently released Water Services (Wastewater Environmental Performance Standards) Regulations 2025 allow.
No changes will be made to the current consent conditions, so the enhanced treatment and disinfection means that any risk to recreation or food gathering in the bay would be negligible.
The pipeline can be constructed from the existing wastewater treatment site compound using remote tunnelling techniques for around 550m to avoid damage to the foreshore and beach use, and then with a buried pipeline across the seafloor to a location about 3km out to sea.
The treated wastewater from the new plant would be piped to the existing treatment plant site to connect to the ocean outfall pipeline.
Alternative discharge
The existing consent requires us to explore alternative discharge options for the high-quality treated wastewater. These options are being explored in partnership with Patuharakeke Te Iwi Trust Board.
Options include possible discharge to the Ruakākā River, the Whangārei Harbour or Bercich Drain, and retaining the existing land disposal at Rama Road or a combination of these options.
Initial investigations have confirmed that the Bream Bay area has high water tables and very limited suitable land available in the rohe. However, recognising that land-based discharge is preferred by some over discharge to waterbodies, several options to incorporate land-based discharge are being considered through maximising existing discharge to land in combination with the other disposal options.
A decision on the preferred discharge option will be made by Council once all the investigations are complete (likely around mid-2026).
There are no significant opportunities at this time for beneficial reuse of the water for irrigation or commercial use, but our design will enable this should a future opportunity arise.
Expected high-level timeline 2026 to 2030
Preliminary design scope 2025 to 2026
For each of the three workstreams (treatment plant upgrade, ocean outfall and alternative discharge), consultants have evaluated options which included, amongst other things, investigating and assessing ecological and geotechnical conditions, archaeological site screening, cultural impact screening, landscape and amenity impacts, as well as developing a picture of the likely costs of implementation and operation. Our hapū partners, Patuharakeke Te Iwi Trust Board, have been involved in much of this work.
This preliminary design work informs the business case, which will allow Council to make final decisions about options, such as the location and scheme of the new treatment plant and whether to use the consented ocean outfall discharge option or an alternative discharge option.
We will engage with the community to understand views about the options before finalising the business case, expected mid-2026.
Detailed design – 2026 to mid-2028
This phase details out the exact design of the preferred options to have been identified from multi-criteria analysis for each part of the project (treatment plant, ocean outfall or alternative discharge method).
Following detailed design, key documents will be produced and Council will start a competitive tender process to select the preferred construction company(s) for the project.
The ocean outfall workstream may be tendered as a design and build project.
Construction – 2027 to 2030
Construction of parts of the scheme is expected to begin in 2027, with the overall scheme expected to be operational around 2030.
We will work with the community to manage the impacts of construction work, which may include additional truck movements and increased dust and noise in the immediate vicinity of the works.
Interim solution 2025 / 2026
As the existing plant is nearing its capacity, we are currently unable to grant any additional connections to the wastewater treatment plant. This is constraining growth in the area.
To address this, we are creating additional discharge capacity, which will allow consenting of new connections to start again in 2026 while the new treatment plant and discharge options are being built.
We have now applied for a consent to expand the existing discharge area into the Poupouwhenua Reserve adjacent to the existing wastewater treatment plant (see the site plan above).
We have also applied for a Department of Conservation (DoC) concession as the area is a scenic reserve administered by DoC.
If our consent and concession applications are successful, the interim solution should be operational in around June 2026.
Advice for developers
As mentioned above, the constraints on the discharge capacity of the existing treatment plant have meant Council is not able to grant further consents that include connections to the treatment plant until the upgrade is complete or an interim solution is found.
The interim solution will free up some additional capacity until the upgrade is complete.
Our estimates for what additional capacity will be made available are:
- Likely increase in capacity: 500m3 per day.
- This equates to capacity for approximately 1,000 additional Household Unit Equivalents (HUE).
- The existing consenting pipeline includes applications for 216 HUE, which will be honoured first.
- This leaves residual further capacity of around 784 additional HUE available for consenting from when the additional capacity comes online (likely mid-2026) until the new treatment plant is operational (likely 2030).
Long Term Plan 2024-34 provides funding for this project
You can read previous Council papers about Ruakākā wastewater management here:
Location
Ruakaka Pipeline Road Track, Ruakākā 0116 View Map
-35.86555864914647, 174.46985347099968
Ruakaka Pipeline Road Track ,
Ruakākā 0116
Ruakaka Pipeline Road Track ,
Ruakākā 0116
Ruakākā Wastewater Treatment Plant upgrade