The construction process of the Central Interceptor wastewater tunnel, was started by commencing the 14.7km long journey of the New Zealand water company Watercare’s giant tunnel boring machine (TBM) Hiwa-i-te-Rangi, on 30 July.
Central Interceptor, which is worth NZ$1.2bn (£602M), is a wastewater tunnel that intends to clean up central Auckland’s waterways. It is due to dig underground from Grey Lynn to Watercare’s Māngere wastewater treatment plant and will have several link sewers and shafts along the route for collecting and transferring wastewater into the tunnel. The purposes of its design are to reserve as well as convey wastewater and will clear up 80% of wet weather overflows into Auckland waterways.
The completed tunnel, which is 4.5m in diameter and 14.7km long, is going to be the longest bored wastewater tunnel in New Zealand and the determined date for finishing this work will be 2025. Auckland mayor Phil Goff gave the order to launch the TBM at a launch ceremony at a construction site next to the Māngere wastewater treatment plant. He commented: “This is a great day for all of us who care about Auckland’s water quality.”
According to a contract which was concluded between Watercare and Ghella Abergeldie JV in March 2019 for construction of the Central Interceptor wastewater tunnel, in November 2019 the required TBM was ordered from a Germany-based manufacturer Herrenknecht. September 2020, was the date of completing the TBM by Herrenknecht, then separated and transmitted to New Zealand, where it arrived in November 2020.
In June the sections of TBM Hiwa-i-te-Rangi were carried into a shaft at the Māngere pump station site, and it was then assembled underground.
“It’s a big achievement – it comes from the dedicated work of both teams, Watercare and Ghella Abergeldie joint venture,” Ghella Abergeldie JV project director Francesco Saibene said of the commencing of the tunnel construction.
In accordance with Watercare executive program director of Central Interceptor Shayne Cunis statement: “It’s a great day, there’s a lot of hard work that’s been going into this project and it’s a great testimony to the efforts of the team so far. We’re well on our way to delivering the solution for the people of Auckland, and it is full steam ahead from here.”
The intended date of beginning pipe-jacking to excavate two link sewers that are due to link to the Central Interceptor by the micro TBM Domenica, is June 2022.