Beachlands WWTP discharge consent renewal

Project overview

The Beachlands and Maraetai communities are growing and our wastewater treatment plant (WWTP) is nearing the end of its design life. With the WWTP consent up for renewal on December 31, 2025, upgrades are essential to continue providing services and meet future demands. This includes exploring alternative wastewater discharge locations.

Options consideration

We engaged independent specialists to assess potential options for wastewater treatment quality and discharge locations. These options were evaluated using a clear methodology and various criteria, aligned with project objectives.

The project team identified 20 potential solutions, taking into consideration community needs and best practices globally. These were narrowed down to five short-listed options after community feedback on 26 October 2023 at Te Puru Community Centre. There were also online surveys for those unable to respond in person.

After careful consideration and evaluation of a range of discharge options, we have identified option 2a - a diffuse discharge to a tributary of Te Puru Stream, as the preferred technical option for the future discharge from the Beachlands Wastewater Treatment Plant site.

While option 2a is the preferred technical option, we remain committed to consulting with Mana Whenua, Ngāi Tai ki Tamaki, to further refine and develop this option for the discharge of wastewater from the Beachlands Wastewater Treatment Plant.

We appreciate the ongoing collaboration and input from all stakeholders as we continue to prioritise public health of the Beachlands and Maraetai community, environmental outcomes, cultural wellbeing, and the requirements of the community in our decision-making process.

Stages of implementation

Stage 1

The ongoing discharge of treated wastewater from the existing WWTP without any upgrade works, with a maximum discharge volume limit of 4,500m³/day, and an average daily flow of 2,200m³. This will cater for a population of up to 11,000 people.

Stage 2

The undertaking of short-term upgrade works to cater for a population of up to 18,000 people, a maximum discharge volume limit of 8,700m³/day, and an average daily flow of 3,600m³. The upgrade works will include:

• Replacement of the existing inlet screen

• Increasing the aeration capacity of the lagoon and the pipework from the ultraviolet (UV) treatment area into an increased capacity overland flow area

• Installation of new recycled pumps and pipework, an additional tertiary filter and additional UV lamps

• Construction of additional sludge drying beds

• Upgraded mains power supply and distribution boards.

Stages 3 and 4

The undertaking of long-term upgrades in two stages. The stage 3 works will cater for a population of up to 24,000 people and a maximum discharge volume limit of 28,900m³/day, and an average daily flow of 4,800m³.

The stage 4 works will cater for a population of up to 30,000 people and a maximum discharge volume limit of 36,200m³/day, and an average daily flow of 6,000m³.

These upgrade works will result in the current lagoon being replaced by concrete tanks known as activated sludge reactors, while the current filtration system will be replaced by new ultrafiltration and membrane bioreactors. This will allow for removal of 100% of suspended solids and most micro-organisms (bacteria, viruses etc.). UV disinfection will be retained and expanded to provide an additional level of treatment. Water will still be discharged into the tributary of the Te Puru Stream via groundwater and an overland flow system.

The long-term upgrades are population dependent and will only be implemented once the referenced population numbers are reached.

The consent application was lodged with Auckland Council on 17 June 2024. Submissions closed on 16 December 2024 and are under review.