Gas Bridge over Waikato River at Cambridge
Waipā District Council has explained why the cost to upgrade Te Awamutu Wastewater Treatment Plant rose from $19 million to $48 million.
Finishing works took place on the upgraded Te Awamutu wastewater treatment plant three years ago. From top (L-R): new UV system, clarifier and screen. Bottom (L-R): new electrical room, UV and screen. Photo: Supplied.
The News revealed in November the upgrade costs to the council for the plant, and one in Leamington, were now put at $57 million. The Leamington wastewater reticulation upgrade cost rose from nothing to $9 million.
Dawn Inglis
Before the government repealed the Three Waters reforms last year, the costs for the country’s water supplies, storm and wastewater management systems would have been picked up by the new water service entities.
Responding to questions from The News, council service delivery group manager Dawn Inglis said the Te Awamutu upgrade was included in the 2018-2028 and 2021-31 Long Term Plans.
The increase followed a review of the business case received by the council in late October informing the 2025-34 Long Term Plan budget.
Speaking to the review, Inglis said: “Further capacity is required at the wastewater treatment plant as growth has occurred ahead of what was forecast in 2018.”
“Modelling now indicates the plant as it was proposed would be non-compliant for nitrogen and biological oxygen demand in 2029/30.
“There is now a need for new inlet works to future proof for an eventual membrane upgrade (expected to be required post 2040).
“Geotechnical issues at the current treatment plant site are impacting on the design needed for the next upgrade, which has also impacted cost estimates.”
Inglis said the review noted construction costs had increased significantly for infrastructure projects.
The upgrade will be required to be completed by 2029 to meet discharge limits in the consent.
Gas Bridge over Waikato River at Cambridge
New inlet works at Te Awamutu
