SaniTube rehabilitates a freshwater pipeline in Sweden in one 960m pull
Västervik is a city in southern Sweden surrounded by forests and water. In 2016 a water main connecting a local peninsula needed to be repaired as the existing pipe was leaking and infiltrated with seawater whenever the pumps would be turned off. Due to the size of the body of water the installation needed to be done in a single shot of 960m.
Due to the length of the pipe that needed to be repaired, the client needed a solution that could span the full distance in one pull. SaniTube was chosen for its ease of installation as well as its ability to rehabilitate the full pipeline in one pull.
Additionally, the pipeline was not in constant use, which added an additional layer of complexity to the project. As it ran under the lake, upon reinstating the line the pipe would need to be slowly vented, allowing the water to be pushed out of the pipe before it could be reinstated. When looking for a solution, that client had to consider how the new liner/pipe would react to added pressure from infiltration, while also being able to handle the required venting upon restarting the pipe.
SaniTube was the perfect solution as its flexibility allows it to properly handle any infiltration, while also being able to slowly push out any excess water upon reinstating the pipe.
There were two main challenges regarding the installation of the SaniTube. First, the entrance to the host pipe was located in a forested area, providing difficult access for installation.
Second, the largest reel that SaniTube could be rolled onto could hold 750m of the liner. Due to the length that needed to be installed, the SaniTube needed to be laid out first so that it could be pulled into the pipeline properly.
The installation was successful and the pipe was returned to service within 3 days (incl. cleaning) and it runs smoothly since. The only change in operating the lined pipe after installation was the increased venting time needed when putting the pipe back into service after dewatering it. This is due to the fact that whenever the line is dewatered for a longer period of time seawater has the chance to infiltrate between the SaniTube liner and the host pipe at the lowest point (+20m) of the pipe.
Consequently, when restarting the pumps the operator needs to allow enough time for the infiltrated water to be pushed out of the pipe again when the SaniTube liner is re-pressurized.