22 May 2022

Solution to Urenui sewage leaks one step closer

8:45 pm on 22 May 2022

Raw sewage leaks at popular North Taranaki holiday spots are a step closer to being solved after land has been bought for a wastewater treatment plant.

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A rāhui on swimming and gathering fish and shellfish is in place on the Urenui River, from Okoki Pa to the river mouth. Photo: Supplied

New Plymouth District Council voted this week to spend $3.3 million on 41 hectares of land in Onaero, across two properties.

Waters Manager Mark Hall said the deal would speed up the building of a $31 million plant, which is included in the 10-Year Plan (2021-2031).

"This land came unexpectedly onto the market and it is rare to have something of this size available in the right location, so we acted quickly.

"The Urenui / Onaero wastewater project is in the budget, so it's pleasing we can begin this important piece of mahi to get rid of pollution in this important awa a couple of years earlier than scheduled."

Mana whenua and local residents lobbied hard for a long-term solution to wastewater seeping into the Urenui River.

A Ngāti Mutunga citizen-science project in 2019 first revealed the scale of the problem and proved old septic tanks were the source of contamination in waterways at Urenui and Onaero.

A rāhui on swimming and gathering fish and shellfish has been in place on the Urenui River, from Okoki Pa to the river mouth, since November 2020.

Rūnanga o Ngāti Mutunga Chief Executive Mitchell Ritai said it was great that a site had been identified for this project.

"One of the challenges we've face over these last few years is the amount of discharge from septic tanks into our rivers, especially Onaero and Urenui rivers, and this sees a way for that to be addressed."

Ritai said it was particularly significant for the people involved in the Curious Minds citizens science project.

"So to be able to have a reticulated system that all of our wastewater from our two communities is going into, a plant that allows it to be taken care of so it's not contaminating our waterways, is a real win - a real success for us."

New Plymouth mayor Neil Holdom said Urenui and Onaero had in a sense become victims of their own popularity.

"So if you think about it they're just those cool coastal settlements with old baches that probably people used to go to for a few weeks, and now people are living in them the septic tanks are way past the end of their life and the land has just become saturated, and we've got the leachate coming out of that into waterways."

He said the NPDC had spent the last two years helping residents fix and maintain their septic tanks and working on wastewater issues at both the Onaero and Urenui campgrounds, but there was more work to do.

"The plan will be that if we can secure the consent that we'll build a wastewater plant out there, and instead of putting the treated effluent into a pipeline out to sea, which is what we do in New Plymouth, we'll be discharging to land.

"So the idea is that the land is sufficient to run a discharge-to-land process, and based on our forecast growth for both Onaero and Urenui it should cater for at least 30 years of growth, if not more."

A graphic for the planned Onaero and Urenui wastewater treatment plant. New Plymouth mayor Neil Holdom says: "Here is a picture of what it might look like one day - although we may not be able to grow the coconut trees."

A graphic for the planned Onaero and Urenui wastewater treatment plant. New Plymouth mayor Neil Holdom says: "Here is a picture of what it might look like one day - although we may not be able to grow the coconut trees." Photo: Supplied/ New Plymouth District Council

Ritai said a discharge to land option was preferable to iwi.

"Our preference is always to discharge to land as opposed to discharge to waterways, so it's great that a possible solution could be designed that allows that treatment and that discharge to happen to land."

The next step would be for council to further consult with mana whenua, locals and direct neighbours as part of the consenting process.

By the numbers: New Plymouth District Council's wastewater system

  • NPDC processes an average of 25 million litres of wastewater each day
  • The wastewater is from more than 25,850 properties in the district
  • It flows via 34 pump stations
  • The sewer network covers 631km

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