Maintaining Nelson’s wastewater network is essential in order to keep Nelson running as a city. A key part of that network is the Nelson North Wastewater Treatment Plant (NWWTP), located just off Boulder Bank Drive. The existing resource consents for the NWWTP are due to expire in December 2024, and we want to start the conversation now with our partners and key stakeholders.
Over the last ten years, the plant has been significantly upgraded from just oxidation ponds to help make sure the wastewater is treated to a high standard. As a result, the treated water from the plant consistently meets our resource consent requirements.
The upgrades that have improved the quality of the treated water includes the addition of a pre-treatment clarifier and trickling filter, screening at both the treatment plant and upstream of the treatment plant at the Neale Park pump station (to remove grit and other materials that could potentially cause blockages) and wetlands (that use natural processes to improve the quality of the water). A biofilter, aerators and a cover to the trickling filter have also been added at the plant to reduce odour issues. An upfront buffer storage zone has also been added to assist with storage during major wet weather events.
The last three annual compliance reports showed that the plant is meeting all the stringent discharge conditions of its current resource consent relating to treated wastewater. Odour discharge always remains a challenge and a pond management team (including a microbiologist) monitor performance of the treatment facility on a regular basis.
As part of the resource consent renewal process, Council will be investigating alternative options for the management of wastewater in the region. While alternative options may not be able to be implemented straight away, this consent will start the process to find the best solution for Nelson’s future.
This involves weighing up the benefits and dis-benefits of a range of alternatives against cultural, social, environmental, technological and economic considerations. The outcome of this assessment will be to determine the “best practicable option” for our community and the receiving environment (Tasman Bay).