Major progress on $38m Wellsford wastewater upgrade

Watercare’s $38.3 million upgrade of the Wellsford Wastewater Treatment Plant is firmly taking shape, with foundational works wrapping up and wetland planting now underway.

The upgrade, which began in November last year, will significantly improve the quality of treated wastewater discharged into the Hōteo River – thanks to the introduction of advanced Membrane Aerated Biofilm Reactor (MABR) and Membrane Bioreactor (MBR) technologies.

Watercare wastewater production manager Kenny Williamson says these technologies treat wastewater to a much higher standard.

“These treatment processes are highly effective at removing organic matter and nutrients, largely thanks to the microorganisms – or ‘bugs’ – that do the heavy lifting. We simply create the right conditions for them to thrive.

“The membranes are very effective at removing pathogens, but any that pass through the membranes are further treated using ultraviolet disinfection, ensuring the final discharge meets stringent environmental standards.”

Williamson says the upgrade will support future growth in Wellsford and Te Hana.

“Wellsford is expected to be home to around 5000 people by 2052 – more than double its current population.

“This upgrade lifts the treatment plant’s capacity to about 3200 people, and we’ve designed it to allow for future expansions as the area continues to grow.”

Watercare chief programme delivery officer Suzanne Lucas says construction is progressing quickly, with most of the interconnecting pipework, valves and other instrumentation well underway.

“We’ve also finished installing a seven-metre-diameter timber tank to store water for firefighting purposes – a critical safety feature given the relatively remote location of the wastewater treatment plant,” Lucas says.

“Work is also advancing on the plant’s inlet section, where wastewater first enters the treatment process."

Lucas says the team is now focused on completing the two-storey process building and restoring 1.3 hectares of wetland with native plants that help filter water naturally, stabilise the soil, prevent erosion and bring back the ecological balance of the area.

Watercare is restoring the surrounding wetland with native plants

“So far, we’ve replanted about 70 per cent of the wetland with species like kōwhai, ribbonwood, toetoe and kuta.

"By the end of this month, we expect to have all 15,718 plants in the ground.”

Lucas says the project is moving quickly, with desludging of the oxidation pond scheduled to begin in the coming months and cold commissioning of the plant planned for early next year.

“We’re aiming to have the upgrades at the treatment plant in service by middle of next year.

“Traffic management will remain in place approximately 300 metres on either side of the entrance on State Highway 1, around 2.5km outside of Wellsford, to allow for the high number of trucks and vehicles coming in and out of the site.

“We appreciate the community’s patience and understanding as we work to increase the plant’s capacity and ensure its long-term sustainability.”

An aeriel of the upgrades underway at the Wellsford Wasterwater Treatment Plant