Using SAERTEX-LINER®, TDG Environmental delivered its first pressure installation project in May 2024, positioning the company as a leader in pressure pipeline renewal for New Zealand.
Over eight days, TDG Environmental, one of the largest and most experienced specialist providers of asset renewal in New Zealand, tackled two sections of a 4km DN450 asbestos cement pipe using trenchless UV relining technology.
This project was part of the larger, multi-year works and rehabilitation of the Nelson Regional Sewer System Rising Main duplicate project being delivered by Nelson Regional Sewerage Business Unit.
The project was managed by the client, NRSBU, with support from Beca as the consultant and designers. Hunter Civil was selected as the main contractor for the project, covering the area from the Beach Road pump station to Saxton Creek.
TDG Environmental was chosen as subcontractors to Hunter Civil and was responsible for the trenchless renewal of two critical sections of a rising main which had been decommissioned 15 years earlier due to insufficient capacity.
“A new pipe had been managing the outflow of the Richmond area to the Bell Island Wastewater Treatment Plant,” TDG Environmental General Manager Simon Ganley said.
To help reduce the overall project cost and avoid costly and highly disruptive trenching under the main transport route between Nelson and Richmond, the NRSBU decided to reline the old pipe and bring it back online.
The renewal of the pressurised pipe was crucial to meet the future demands of the growing population and mitigate wet weather overflows. Once in operation, the pipeline would need to withstand operating pressures of 6 bar with a flow rate up to 500l/s.
The renewal involved two segments which ran under State Highway 6,252m and 140m long, and would require a fully structural solution due to the deteriorated state of the host pipe.
TDG Environmental selected SAERTEX-LINER MULTI Type S+XR Pressure, one of the few options on the market suitable for fully deteriorated pipes. This liner is Class A classified according to DIN EN ISO 11295, meaning it is independent and fully structural.
“The liner is tight-fitted and absorbs inner and outer loads independently,” SAERTEX multiCom® Business Development Manager Katharina Helming said.
“It can also withstand operating pressures up to 33 bar in accordance with the diameter, making it a versatile UV-CIPP solution.
“Additionally, the liner has an expected technical design life of 50-years and a smooth surface, which, coupled with low wall thickness, ensure maximum flow rate in supply pipes.”
TDG Environmental participated in SAERTEX multiCom Certified Installer training for gravity and pressure pipe liner installation in March 2022, conducted by SAERTEX multiCom and coordinated by the local distributor Pipe Core.
“Our team was very impressed by the quality of the theoretical and practical training for applications in gravity and pressure pipe systems. We were grateful for this opportunity and commend the efforts of everyone involved in bettering industry standards,” Ganley said.
Since the training, TDG Environmental has completed many successful projects using this leading manufacturer’s product.
To support the successful delivery of the project, John Lampe, the SAERTEX multiCom application engineer who conducted the original training, also attended the groundbreaking project in New Zealand.
“It was very good having John Lampe on-site, especially for the consistency between the training and how the project was delivered on-site. He is very knowledgeable and very familiar with the product,” Ganley said.
With a team of seven, the renewal was completed over eight days, starting with one day of high-pressure water cleaning.
“The first liner was installed over three days, following cleaning, camera inspection, and relining,” Ganley said.
The second install, the longer of the two lines, took five days, using a brand-new UV curing cable.
“Pressure checks went well,” Ganley said.
“Both liners were installed successfully, achieving the specified 9-bar test pressure.”
NRSBU’s extensive planning ensured the project’s safe execution with minimal impact to the adjacent Waimea Inlet, an ecologically significant area and early consultation with the eight Te Tau Ihi iwi ensured they were well informed and understood the objective to reduce the frequency of wastewater overflows.
The collaboration between clients and contractors was pivotal in delivering this project with minimal disruption to traffic on State Highway 6, demonstrating a commitment to mitigating community impact.
The renewed pipeline that was brought back into service will lower the costs associated with reticulation and treatment and minimises overflow risks. The increased capacity facilitates easier maintenance of the assets, ensuring reliability even when sections are offline for repairs.
This project not only benefits the local community by enhancing infrastructure resilience, but also sets a precedent for future projects across Aotearoa New Zealand, demonstrating the importance of innovative and sustainable solutions in infrastructure renewal.
TDG Environmental’s successful completion of this challenging project underscores its expertise and capability in the pressure installation space and highlights its commitment to innovation, quality, and industry leadership, positioning it as a trusted partner for future infrastructure challenges.
This article featured in the October edition of Trenchless Australasia.
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