Nature Calls update 2022

Published on 29 September 2022


Palmerston North City Council is continuing to progress our consent application for the best treated wastewater discharge in the country, ahead of lodging it later this year.  

In September last year, Council chose to have the highest treatment currently available in New Zealand and made a commitment to continue to reduce wastewater in the city, and to consider it as a resource. The treated wastewater would be discharged the Manawatū River 75% of the time and irrigated on land when the river is at below median levels.

We’ve indicated we will be lodging our consent application with the regulator, Horizons Regional Council on 31 December 2022. 

From then, the regional council considers and may choose to notify the consent application as part of its process. Council will continue to do significant work during this process.  

River discharge location close to being confirmed  

Over the past few months, we’ve been doing further modelling on the river and have identified a potential location for where the highly treated wastewater could be discharged from. Currently we’re modelling what that environmental impact would be, and then we will be able to confirm it. We’re continuing to work closely with iwi on this work.   

Land work is progressing 

The land component of our consent application is our most challenging element to complete in time for our consent to be accepted. A lot of work is planned for the next three months.  

In our last update we said we’d identified a large area west of the city, close to our treatment plant, which potentially had the right soil types for absorbing treated wastewater [see map below]. We contacted landowners within this area in about soil testing in May and have now been able to test three properties. Those tests confirmed that the area had the soil types previously identified in our desk top assessment.

We stated at the time and will reiterate that where we tested does not mean we want to use those properties for the irrigation. People who own property in the area identified in the map will also be receiving this update. 

The area identified as potentially having the right soil types for absorbing treated wastewater.

A summary of the soil testing written in August is now also available. The 3 types of soil that were tested for are known as Gley, Recent/Raw, and Pallic.

The report states that the best soils for drainage are those that are recent/raw, and that if that soil type is used, we’d need around 600 to 710ha of land, and 75,000m3 for storage. This is less land than we indicated in September 2021. 

Gley soils were the next most effective for drainage, but only 38% as effective as the recent/raw type, meaning they’d require more land. 

Pallic soils were deemed to be extremely restrictive and could pose a high risk of significant cost escalation. 

The report only details testing on 2 of the properties, as the third property was for sale and the testing was done as part of due diligence. The testing showed that property was not suitable for wastewater discharge.

Please note, Figure 3 has been removed from the report as it identifies individual testing locations on private land. As these were given on a voluntary basis by landowners, we want to protect the locations and their individual test results.

Soils Interpretive Report

We’re looking at applying for a global consent, where we’d get consent for the discharge for a general area, only needing to identify 1 or 2 properties to use as the example for the consent.

This approach would mean we wouldn’t need to procure all 760 hectares needed during the 30+ year consent, in advance of that land being needed. This limits disruption to the farming community. It also means that any potential new Three Waters Agency would be able to determine the best locations based on its needs.  

We are in the final stages of confirming some pilot properties, based on size and soil types, and will be contacting those landowners directly before mid-October.   

We’ll be asking them what their long-term plans are for their properties and if they have any interest in selling or leasing land to us from 2028, when we will need it.   

First look at upgraded treatment plant now available  

Council is committed to having the best treated wastewater in New Zealand, and our proposed methods will have our treatment amongst the world’s best, and just one step away from drinking water.  

There are 2 significant new steps. The first is introducing the removal of nitrogen, which can at high levels affect plant and freshwater life in our awa (river.) The second is microfiltration, which will enable us to remove particles as small as 0.04 microns, which is smaller than the human eye can see and includes things like bacteria and viruses.   

A new video released today shows what our existing treatment plant will look like with these new steps included. Watch it to compare our current processes to our new process.   

This concept video only shows our current proposal, but we’ve also committed to improving the plant or processes if technological advances could further improve the quality of our treated wastewater.   

As part of our consent application, we’re also looking at adaptive management. This includes:   

  • Establishing a framework for managing any environmental risk and uncertainty.  

  • Having a framework for reducing the amount of wastewater generated by the city.

  • A plan for reducing the volume of treated wastewater discharged to the river over the life of the consent .

  • A strategy to establish investigations and actions for the Council to implement over the consent period.

Our project reference group, made up of several stakeholders, technical and iwi representatives is working through this.      

We’ve only got a few more steps before lodging our consent 

With the clock ticking, the next step for our Nature Calls project is to prepare the consent application, pulling together the five years' worth of technical work and assessments. Our reference group will continue to meet and work on the adaptive management strategy.

Due to the impact of Covid-19 on our timeframes, and needing more time for lodging our consent, this week Council brought forward already budgeted money from next year’s Nature Calls budget into this year’s budget. As it was already budgeted money, this has no additional impact on ratepayers.  

While the government is working on the Three Waters Reform, we are legally required to continue with this project as it is a requirement of our consent.  

We will provide another update when we lodge our consent. Once it has been accepted by Horizons Regional Council, we will make it publicly available on our website.   

5 May update

Significant work is underway as Palmerston North City Council prepares to lodge its consent for the future treatment and discharge of its wastewater for up to the next 30 years. 

In September 2021, Council confirmed that it’s future discharge would be a hybrid option, with treated wastewater being discharged to the Manawatū River 75 per cent of the time, and during the remainder of the time a combination of land and river. Council also committed to having the highest treatment in New Zealand. 

Since then, eight major pieces of work required as part of our consent application have gotten underway. These include further modelling of wastewater with various population projections for the next 50 years, monitoring the river water quality and ecology, designing the new additions for our treatment plant, determining the pipe requirements for the land discharge, working on mitigations for any impact on the river or land, finding suitable areas for land discharge

Land testing due to start

Chief Infrastructure Officer Sarah Sinclair says the option requires us to locate land where irrigation could occur, but we don’t need to have purchased the land at the time we lodge consent.

“To identify this land, we need to test soil. We will be doing that west of Palmerston North, including some properties in the Manawatū and Horowhenua Districts. We have selected some properties where we would like to test to give us a good cross section of soil types and will be contacting those landowners. We’ll also be letting people in the community know that we are testing, as we may need to test other sites as well.”

Ms Sinclair says testing land is not necessarily an indication that Council would like to purchase that land.  

“Palmerston North City Council have always said we would like land purchases to be on a willing buyer/willing seller basis, so over the coming years we’d be looking to have those conversations and carry out further testing if needed. If large properties come up for sale in Palmerston North’s west, and close to our treatment plant, then we will consider testing it, and may consider purchasing. We will be working closely with landowners over the coming weeks and months directly as we work through this process.” 

Consent application to be lodged this year

Our wastewater consents expire in 2028. We were due to apply for new consents by June this year however over the past two years there have been significant delays to our work programme due to COVID-19 lockdowns affecting both public engagement, and the wide range of scientific and technical tests needed to prepare our consent application.  

We have advised Horizons Regional Council that it will take us until the end of 2022 to put forward our new consent application. Horizons has acknowledged the likely programme delay and is aware of the significant and complex work that Council have done to develop our best practicable option and progress the consent application. 

This wont affect our ability to design and build the new treatment or discharge requirements in time for the 2028 consent expiry.

Ms Sinclair, says although this is a difficult decision, its one we have to make.  

“We take our legal and environmental responsibilities very seriously, but the pressures placed on our technical teams by the pandemic mean we will not be able to complete important scientific analysis for the modelling of our river for the future, wetland options or land testing by June.  Protecting our environment and ensuring the best outcomes for our community have always been our top priority, and we need extra time to ensure we can do just that.” 

She says Council has informed local and regional iwi and hapu and key stakeholder groups that we would need to seek this extension, and have the support of Rangitāne in acknowledging that the delay is necessary to deliver a complete consent application.  

Stakeholders also continuing to feed into Nature Calls

We have already committed to having the best-treated wastewater in New Zealand, but our Council has also committed to constantly looking at how we can do better over the life of the consent. We’re working with our Project Reference Group and technical experts about how we can do this. The key components include how we will reduce the amount of wastewater over time, reducing the volume of treated wastewater entering the river, how we can re-use components of the wastewater and a strategy for how we will respond to any environmental uncertainty or innovative technology over the life of our consent.  

Our Project Reference Group first met in February and meets monthly to help guide Council officers and consultants about the management and treatment of our wastewater in the future, and feed in ideas for the adaptive management strategy. Having such a diverse range of groups involved means everyone gets to hear each perspective.  

More updates throughout 2022

We will continue to provide our community updates throughout the year, and a deeper look at some of the technical work we are doing.  

All information about Nature Calls is available at

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