During the rehabilitation of the main water line in Hötensleben, the local water and wastewater utility TAV Börde faced major challenges. Due to the demanding route layout and narrow access paths, the egeplast ege-Liner® was used in a close-fit lining process – an efficient and environmentally friendly solution.
Ecologically compatible process
Even during the necessary preparatory work for the rehabilitation project in Hötensleben near the former inner-German border, the commissioned Esders Pipeline Service GmbH had to overcome special challenges in September 2022. For example, a filter gravel pack had become detached from a pump system, leading to increased deposits in the old pipe, which had to be removed with the help of a high-pressure cleaning system.
Existing bends, reductions, and various old pipe materials such as cast iron, steel, PVC, and asbestos cement pipes made the rehabilitation measure more difficult. In addition, the route layout created further challenges, as it largely ran across agricultural land and, in some sections, through residential areas. Last but not least, narrow access paths and severely restricted traffic spaces in parts of the rehabilitation section complicated the implementation of the project.
When selecting the rehabilitation method, the decision was therefore made in favor of soil-conserving and ecologically compatible PE relining without an annular space (close-fit lining) according to DVGW worksheet GW 320-2. With this deformation process, construction pits only need to be excavated selectively. Just as resources are conserved, fertile soils (such as the humic topsoil layer) are protected, and the surrounding nature is not unnecessarily burdened.
Effort and costs significantly reduced
After exposing and cutting out the respective pipe sections in the construction pits, the existing drinking water pressure pipeline was inspected for any obstacles, deposits, contamination, or damage to the pipeline. Following high-pressure cleaning, a final calibration of the old pipeline was carried out in order to pull in the new pipe, the egeLiner®, via the launch pit.
The creation of the insertion and target pits as well as the exposure of the existing old pipeline were carried out by SPIE Versorgungstechnik GmbH Gommern on behalf of TAV Börde. The pulling device, usually a capstan winch, pulls the folded egeLiner® from the drum through the launch pit into the old pipeline to the target pit. This demonstrates one of the major advantages of the deformation process compared to the classic pipe string method with an annular space. Since the minimum bending radius of the close-fit liner is significantly smaller than that of a normal pipe string lining with an annular space, the dimensions of the construction pits can be reduced. As a result, the excavation effort and thus also costs and other disruptions are significantly reduced, also because no pipe string has to be pre-stretched above ground and pre-welded to the length of the section. The respective section lengths are produced at the factory on a project-specific basis and delivered on drums.
Final work steps
Successful installation was followed by the final steps of pressure testing and disinfection or bacteriological examination before the rehabilitated pipeline could be put back into operation.
The connection to the existing old pipeline was made at the construction site in Hötensleben using standard PE pipe OD160 SDR17 PN10 with the help of relining electrofusion sockets DN150/160 and previously inserted stainless steel support sleeves, as the egeLiner® has a slightly smaller outer diameter than the standard pipe.
In total, Esders Pipeline Service rehabilitated around 650 m of dilapidated drinking water pipeline in Hötensleben.
Project Description
Rehabilitation of a 650 m long main water line DN150
Challenges
Restricted accessibility of the route, cramped space conditions above ground, bends, heavy encrustation and deposits, hydraulic capacity
Solution
Trenchless rehabilitation using close-fit lining
Installation
Deformation process
Pipe System
egeLiner® DN150 SDR17 made of PE 100-RC
Project Participants
Client: TAV Trink- und Abwasserverband Börde
Planning, installation: Esders Pipeline Service
egeplast
egeLiner®
The pre-shaped egeLiner® is wound onto steel drums, tailored to the length of the section being renovated. This achieves a cross-sectional reduction of up to 40 percent, allowing long construction lengths to be delivered to the site.
Fundamentally, the folded egeLiner® pipe strives to equalize the stresses frozen in its wall and transform back into its round original shape — this is referred to as the reversion process, which causes the return to the original form (“memory effect”). This property makes the close-fit method highly efficient and ensures that, after successful Installation, the egeLiner® adheres closely to the inner wall of the old pipe and can be fully integrated into the existing pipeline network without restriction.
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Source: Sustainability
