Amiblu GRP Pipes Power Sarpsborg’s Largest Wastewater Upgrade

Country

Norway

City

Sarpsborg

Timeline

2025

Application

Sewer

Total Length

5000 m

+

Sarpsborg Municipality in Viken, Norway, is undertaking one of its largest wastewater infrastructure projects: the expansion and modernisation of the Alvim Wastewater Treatment Plant and its connected sewer network.

The existing Alvim wastewater treatment plant, built in the late 1980s, no longer meets current discharge limits or capacity requirements. Population growth and stricter nitrogen and phosphorus standards required a comprehensive upgrade to increase capacity from approximately 65,000 PE to 95,000 PE by 2050 (PE = Population Equivalent: treatment capacity of a WWTP).

As part of this upgrade, Amiblu was chosen to supply glass-reinforced plastic (GRP) pipes for the wastewater transport network leading to the plant. The delivery comprises about 5 km of pipelines: approximately 1 km of NC Line non-circular sections with dimensions of 1200 x 800 x 600 mm, and around 4 km of circular GRP pipes ranging from DN 400 to DN 700. All pipes have a nominal stiffness of SN 10,000 and pressure ratings from PN 1 to PN 20. Installation is carried out in open trenches by Råde Graveservice AS, contracted by Sarpsborg Municipality.

This is the first time NC Line (non-circular GRP) pipes have been installed in Norway, introducing a proven international solution to improve hydraulic efficiency in Norwegian wastewater systems. As Kjell Arild Karlsen, Project Manager at Råde Graveservice AS, explains:

«The egg-shaped NC profile gives a reduced cross-section at the bottom, which means that even with low water flow, the pipes remain self-cleaning. That was the main reason for choosing this solution.»

Installation takes place in an open farmland area with soft topsoil, requiring careful excavation and reinstatement of agricultural soil after construction. Limited soil cover above the pipeline influenced the design and material choice. Construction began in April 2023 and is scheduled for completion at the end of 2026, with trial operation starting in January 2027. Once commissioned, the upgraded facility is built to meet current environmental standards and future regulatory requirements. The new pipelines are designed to deliver efficient hydraulic performance and minimise maintenance requirements over the long term.

Karlsen also highlights the strong collaboration throughout the project:

«The collaboration with Amiblu has been very good. From day one, we have had excellent communication and solved the biggest challenges together. We even visited the factory to learn more about GRP, which is not very common in this part of the country. And generally, they are great people to work with. So, it results in a good solution.»