Council & City

Nature Calls: A fresh look at how we manage wastewater

This project takes a fresh look at how we manage wastewater in Palmerston North and what we’ll need to achieve before 2022 to bring our wastewater management and infrastructure up to a future-proofed standard.

Palmerston North's wastewater system is under pressure from a growing population and high expectations around discharge standards and river water quality. Nature Calls is our four-year planning, investigating and engagement project that will result in the delivery of the best practicable wastewater treatment option for our city and our awa.

What is wastewater?

Wastewater is the liquid waste that is flushed or washed into the drains at houses and businesses. It comes from toilets, showers, baths, dishwashers, washing machines, sinks and commercial or industrial processes. Palmerston North City Council is responsible for collecting and treating the majority of the city’s wastewater and every year collects up to 12.9 billion litres of wastewater from more than 87,000 people from 25,300 connections.

What this project is about

Council’s vision for Nature Calls is to identify an option that will enable growth, protect and enhance the environment, and contribute to improving the health and mauri of the Manawatū River.

Most of the city’s wastewater is currently delivered to the Tōtara Road Wastewater Treatment Plant. Contaminants are removed before it is passed through a wetland pond for further treatment, and then discharged to the Manawatū River.

This discharge requires a resource consent, and Council will need to apply for a new consent by June 2022.

Nature Calls is investigating the full range of options for treating and discharging wastewater. We will need a wide range of technical, scientific and planning inputs as well as feedback from tangata whenua, the Palmerston North community and other stakeholders.

Infographic shows how wastewater is treated in Palmerston North, from input, through screening, to discharge.

Tap the magnifying glass to expand and see how wastewater is currently treated in Palmerston North.

Palmerston North’s current wastewater system is made up of three treatment plants (a large one at Tōtara Road and smaller, supporting plants in Ashhurst and Aokautere), one oxidation pond, and 404 kilometres of pipeline. There are 34 pump stations, 5,679 manholes, 277,873 lateral pipes and 109 valves.

In Palmerston North, we’re supplied with water from the Turitea Dam in the Tararua Ranges. When it leaves our homes and businesses as wastewater, it travels through the small diameter underground lateral pipes from the house or business into the reticulation network which is made up of the pipelines, manholes and pumping stations. From there it goes into the treatment plant. After treatment, and only once it meets the requirements set by law, it gets discharged into the Manawatū River.

What will this work cost?

Bringing our wastewater management and infrastructure up to a future-proofed standard won’t be cheap.

Nature Calls is the largest single project that the Council has ever planned to undertake and will involve significant capital and on-going operational costs. We estimate that $128.8m is the most appropriate figure to budget for before the full options assessment is undertaken.

As the various options for this project are developed and costed – in consultation with the public – they will be built into Council budgets, with changes addressed through the Annual Budget and 10-Year Plan processes.

A staged approach

Nature Calls requires planning, investigating and lots of engagement, so it will happen across a number of stages.

Within an alternative assessments process we’ll look at the full range of options and identify what’s best for Palmerston North. This includes looking at the effects of each option on the natural environment, as well as social, cultural and economic effects.

Then during the consenting process, all the resource consents that are needed for the future scheme will be applied for. These need to be lodged with Horizons Regional Council by 1 June, 2022.

As part of the 2018-28 10-Year Plan consultation, Council asked for thoughts on upgrading the wastewater treatment plant. Of the responses we received to this question, 72 per cent were supportive of Council using this proposed staged approach.

Where are we now?

Earlier this year we developed a longlist of 26 options for how we treat and discharge Palmerston North’s wastewater in the future. We worked with technical experts to assess these, and a shortlist of six options has now been selected to explore even further.

During the next 12 months Council will investigate the shortlisted options in more detail, to understand the type of treatment required for each.

Got a specific question or would like to know more?


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