Trenchless technology protects ecosystem
Working in partnership with RELINEEUROPE GmbH, the Hamburg branch of Swietelsky-Faber GmbH has successfully completed an exceptional pipeline rehabilitation project on the island of Juist, an ecologically sensitive area. Employing the innovative Alphaliner PN—the first time it has seen use in Germany—has enabled the wastewater pressure pipeline to be rehabilitated efficiently as well as doing much to protect the island’s unique natural landscape.
High-tech solutions for a sensitive ecosystem
Locals on Juist faced a significant challenge when signs of significant damage were spotted on the DN 450 wastewater pressure pipeline that transports the island’s sewage to the treatment plant. The pressure pipe had to be taken out of use and a temporary replacement laid above ground as a workaround. ARGO, a firm of engineers from the town of Norden, was tasked with devising a technical solution that would allow part of the pipeline to be rehabilitated quickly and cost-effectively and ensure safe, secure, and smooth operation.
After carefully weighing up the possible approaches, the engineers opted for the pipe liner method, which enabled the 235-meter-long wastewater pressure pipeline to be rehabilitated efficiently, without any extensive earthworks, and with only minimal intervention required in the island’s infrastructure. Swietelsky-Faber handled the trenchless rehabilitation of the pressure pipe and installed the liner, while the civil engineering work was done by Ludwig Bold GmbH & Co. KG, which laid the trenches required for the planned draw-in of the liners and cut off the existing pressure pipe inside these trenches.
Logistical challenges on Juist
Working on the car-free island of Juist, which is part of the Wadden Sea UNESCO World Heritage Site and the Lower Saxon Wadden Sea National Park, presented the team with some unique logistical challenges. For instance, only vehicles weighing up to 7.5 metric tons are allowed on the island, and only then if they have a special permit. This required materials to be transported by ferry and the whole process planned precisely.
Project coordinator Dimitri Bezmenov, manager of Swietelsky-Faber’s Hamburg branch, underlined the complex planning and organization involved: “The particular challenge we faced didn’t just lie in rehabilitating the pressure pipe using GRP liners. Much trickier was all the meticulous planning and coordination of the various specialists working on site.”
Innovative environmental protection technologies
The project employed state-of-the-art trenchless technologies that ensured only minimal intervention in the island’s fragile ecosystem. Wastewater pressure pipes with a diameter of DN 450 and a pressure level of PN 10 were rehabilitated in three stages with the help of RELINEEUROPE GmbH’s Alphaliner PN, which was developed specifically for pressure pipelines.
Using the tried-and-tested winding method, the Alphaliner PN is made from a GRP glass composite specially designed for the purpose and is impregnated at the factory. It is highly resistant to the kind of dynamic loads that occur under compressive stress as well as to wastewater. Since every element of the liner is manufactured at the company’s factory in Rohrbach, it can be custom-made for every project with a resistance of up to pressure level PN 25 and delivered to the site ready for installation. In this case, the liner was designed with the right nominal width (DN 450) and pressure level (PN 10) in line with the project’s specific requirements.
With its specially developed glass composite structure and a diffusion coating on the inside, the Alphaliner PN ensures long-term sealing and exceptional compressive strength after being cured with UV light, while its smooth surface improves hydraulic performance. The liner can be manufactured in individual lengths of up to 280 meters and installed without any repeat couplings or welding beads.
A resource-efficient Class A solution
The fact that UV-light curing also allows the rehabilitation work to be carried out in a resource- and energy-efficient way puts this solution in Class A in structural terms in accordance with DIN EN ISO 11295 for the rehabilitation of pressure pipelines thanks to the outstanding compressive strength of the GRP material.
Bespoke connection technology
Much of the project revolved around the connection technology that RELINE supplied custom-made in its capacity as a full-system provider. The Alphaliner PN was complemented by specially designed CIPPJoint connection techniques and sealing collars to ensure a safe and secure connection for the rehabilitated pipeline sections that will stay leak-tight over the long term.
Benefits of the rehabilitation method
As well as being kind to the environment, the virtually trenchless rehabilitation method also represented excellent value for money. Projects of this kind can usually be found in urban settings, where minimal intervention in traffic operations and people’s daily lives is key. The structural conditions on site allowed 235 meters to be rehabilitated using just four trenches. This enabled the impact on Juist’s idyllic yet sensitive natural landscape to be minimized, which—aside from its environmental benefits—also kept the project cost-effective.
Conclusion and feedback
With the successful installation of the Alphaliner PN, Swietelsky-Faber and RELINEEUROPE have set new standards in the sustainable rehabilitation of pressure pipes. This project is a striking example of how modern technologies can be combined with a strong sense of environmental awareness to deliver efficient solutions in sensitive ecosystems.
Our particular thanks go to the whole team on site as well as to our client for the trust it has placed in Swietelsky-Faber’s expertise for many years.
02.01.2025, 12:50 Uhr, aktualisiert 02.01.2025, 14:32 Uhr
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