Whangārei Wastewater Treatment Plant Consent and Master Planning
At a glance
The Whangārei Wastewater Treatment Plan (WWTP) faced capacity issues and operational challenges alongside Whangārei District Council’s need to renew the necessary discharge consents. An improvement plan was important to future-proof the facility, accommodate growth demands and deliver high-quality treatment to meet regulatory requirements.
The challenge
Whangārei District Council needed to renew the resource consent for the Whangārei WWTP by the end of 2021 to maintain its right to continue operating the plant. The WWTP serves a population of 65,000 which is forecasted to grow by another 30,000 people over the next 30 years.
Since construction in 1968, the WWTP has undergone multiple expansions and upgrades. This has left a facility with a mix of aging assets, a complex configuration and little room for future expansion. Now at capacity, it faces the need for major replacements and upgrades. Significant inflow and infiltration in the wastewater network create additional challenges, especially during wet weather, whilst advancements in treatment technology provide opportunities to improve the WWTP performance.
Adding complexity, New Zealand’s regulatory framework for environmental projects is evolving, raising potential compliance challenges in the future. Stakeholders needed assurance that environmental outcomes would be met while maintaining flexibility through an adaptive approach to wastewater management.
An improvement plan was important, not just to future-proof the facility and meet growth demands, but also to support high-quality treatment and beneficial reuse of treated effluent.
Our response
Given that many stakeholders, including council staff, lacked established relationships, fostering strong connections took time and dedication. However, through active and meaningful participation, the group contributed invaluable insights and feedback, enriching the entire process.
Workshops with Whangārei District Council and the wastewater working group helped identify the key drivers for both current and future upgrades. From this, the team developed a priority list of improvements and created an augmentation plan to address short-term capacity issues and existing compliance requirements.
To shape the longer-term strategy, the team conducted a consenting strategy review, gap analysis and initial optioneering. This led to the decision to adopt an Adaptive Pathway Planning approach, resulting in a ‘living’ Master Plan.
The Master Plan outlines an initial ten-year capital works programme, with further upgrades implemented over time in response to robust monitoring and evolving factors such as legislative change, plant capacity and performance, population and environmental effects like odour.
This Adaptive Pathways Planning approach was also embedded in the proposed consent conditions and environmental monitoring framework, allowing the Council to remain flexible in its capital planning and avoid investments that might later become obsolete.
The impact
Our close partnership with Whangārei District Council and collaborative approach with stakeholders, fostered coordination and quick, informed decision-making enabling the renewal consent application to be lodged within the necessary timeframes and with broad support from the working group members. The application was notified and all six submissions in opposition or support with conditions were resolved.
The living Master Plan served as a solid foundation for the Council to develop a strong business case, helping to set clear expectations and justify funding for the augmentation and future upgrades in the 2024 Long Term Plan.
While compliance with discharge limits and maintaining receiving water quality, as outlined in the Regional Plan, is the Council’s primary objective, the plan also includes thorough monitoring. This, along with regular updates to the Master Plan, gives the Council the flexibility to adapt and refine its long-term strategy for the plant, ensuring it meets its key outcomes.