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—for the first time in Germany—has enabled the rehabilitation of the wastewater pressure pipeline efficiently while helping to protect the island’s unique natural landscape.
A high-tech solution for a sensitive ecosystem
Locals on Juist faced a significant challenge when substantial damage was 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 operation, and a temporary above-ground replacement was laid as a workaround. ARGO, an engineering office located in 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 while ensuring safe, secure, and smooth operations.
After carefully weighing the possible approaches, the engineers opted for the pipe liner method, which enabled efficient rehabilitation of the 235m wastewater pressure pipeline without extensive earthworks and with only minimal intervention required in the island’s infrastructure. Swietelsky-Faber took over 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 excavation pits required for the planned insertion of the liners and cut off the existing pressure pipe inside those pits.
Logistical challenges on Juist
Working on the car-free island of Juist, part of the Wadden Sea UNESCO World Heritage Site and the Lower Saxon Wadden Sea National Park, presented the team with 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, necessitating precise planning of the entire process.
Dimitri Bezmenov, project coordinator and head of the Swietelsky-Faber Hamburg branch, emphasised the complex planning and organisation: “The particular challenge we faced was not only the rehabilitation of the pressure pipe using GRP liners, but the meticulous planning and coordination of the various specialists working on site proved much trickier.”
Innovative environmental protection technologies
The project employed state-of-the-art trenchless technologies that minimised the impact on 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 using RELINEEUROPE GmbH’s Alphaliner PN, which was developed specifically for pressure pipelines.
The Alphaliner PN is manufactured from a specially designed GRP glass composite using the proven winding process and is impregnated at the factory. It is highly resistant to the 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 each 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 appropriate 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. Overall, the liner can be manufactured up to a single length of 280 metres and installed without imperfections.
A resource-efficient Class A solution
Curing using UV light also enables rehabilitation work to be carried out in a resource- and energy-efficient manner, which means that this solution is statically assigned to classification A according to DIN EN ISO 11295 for the renovation of pressure pipelines, due 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 provide a safe and secure connection for the rehabilitated pipeline sections that will remain leak-tight over the long term.
Benefits of the rehabilitation method
As well as being environmentally friendly, the trenchless rehabilitation method also represented excellent value for money. Projects of this kind are usually found in urban settings, where minimal impact on traffic and people’s daily lives plays a crucial role. The structural conditions on site allowed for 235 metres to be rehabilitated using just four excavation pits. This enabled the impact on Juist’s idyllic and sensitive natural landscape to be minimised, which, aside from its environmental benefits, also kept the project cost-effective.
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.
