Commissioning of Kerikeri wastewater plant underway

Published on 14 August 2020

Kerikeri Wastewater Treatment Plant - Sequencing batch reactor 2 Aug 2020.jpg

Construction of Kerikeri’s much-anticipated new wastewater treatment plant is nearing completion with the inspection of mechanical and electrical components now underway. 

The inspection is part of the plant’s commissioning process and checks every element of the treatment plant, including all mechanical and electrical components, and instrumentation. Commissioning also initiates the biological processes at the heart of the treatment plant so it is ready to receive and treat wastewater. This work is due to run until the end of November 2020 and will involve engineers, contractors, suppliers, Council staff and the Council’s alliance partner, Far North Waters.

Once the process is complete, homes and businesses in the extended area of benefit will be connected to the new sewerage system. This ‘cut over’ work to link homes to new reticulation is due to be completed by April 2021. 

Mayor John Carter says the new plant and reticulation system will be a game-changer for Kerikeri. “Property owners will be relieved the end is now in sight for the $27 million project. There have been delays, and I acknowledge that has been frustrating for homeowners and businesses. However, I am confident we now have a facility that will more than meet the town’s growth for decades to come.”

The new plant will be able to treat 1000 cubic metres of sewage a day and can also be expanded to meet Kerikeri’s growth to eventually treat up to 2000 cubic metres of sewage a day.

The project has also meant expanding the sewerage network around Kerikeri. This has already added 350 existing homes and businesses that currently use septic tanks to the reticulated sewerage system. Ultimately, a further 2000 properties will be able to connect.

Mayor Carter says completion of the project will significantly reduce Kerikeri’s reliance on on-site disposal systems and allow it to use urban land more efficiently.

The final phase of the Kerikeri wastewater project will be to decommission the existing and aging treatment plant in Shepherd Road. This is due to occur once cut over to the new reticulation system is completed in April 2021.

Meanwhile, a $6 million upgrade to Paihia Wastewater Treatment Plant to ensure it complies with its resource consent has been completed ahead of time. Work at the plant began in July 2019 to install 552 bioshell reactors in the second oxidation pond together with the aeration pipework, blowers and a generator. Each bioshell is made up of three plastic domes and are submerged in the treatment pond along with a special media that provides an ideal growing environment for the bacteria that treat ammonia. The domes were all installed prior to Christmas and ammonia levels immediately improved. The project was completed in March, two months ahead of schedule and a deadline set by the Environment Court.

Testing undertaken in February showed a 95 per cent removal of ammonia, with readings of less than 2mg/l. The resource consent limit for ammonia is 2mg/l.  Latest tests undertaken by Northland Regional Council show ammonia levels of less than 0.5mg/l.

The Environment Court has commended the Council for resolving a difficult and sensitive issue in a timely and cost-effective manner.