The Municipality of Nijmegen, home to 182,000 residents, is the largest municipality in Gelderland and the tenth largest in the Netherlands. The municipality ensures the safe transportation of millions of liters of wastewater daily through its underground sewer system.
Gaining insight into the exact condition of their aging asbestos-cement wastewater pipeline for two reasons. This pipeline is nearing the end of its lifespan, and area development is planned along one-third of the route. This is an opportune moment to consider whether the pipeline should be replaced simultaneously.
An inspection with the Acquarius tool. This tool is capable of doing an complete condition measurement of an existing force main in one run.
The Municipality of Nijmegen, home to 182,000 residents, is the largest municipality in Gelderland and the tenth largest in the Netherlands. The municipality ensures the safe transportation of millions of liters of wastewater daily through its underground sewer system. A need arose for the inspection of an aging asbestos-cement pressure pipeline, partially lying under a green strip and partially under a busy road. The municipality wanted the pipeline inspected on several aspects: leaching of AC, wall thickness, pipe location, axial deformation, leaks, and the joint width and angular deflection of the couplings. The Acquarius emerged as the most suitable and comprehensive tool for this task.
For the Municipality of Nijmegen, it was crucial to gain insight into the exact condition of their aeging asbestos-cement wastewater pipeline. This pipeline was selected for inspection for two main reasons. Firstly, the age of the pipeline was an important factor; it was nearing the end of its theoretical lifespan. Secondly, and perhaps more importantly, an area development project was being prepared along one-third of the pipeline’s route. This development would include the construction of buildings, infrastructure, and roads. Such activities typically prompt consideration of whether other renewals, such as replacing an old sewer line, should be carried out simultaneously. After the area development, it would no longer be easy to reopen the street due to the costs, disruptions, and sustainability considerations. The Municipality of Nijmegen wondered whether the selected pipeline should be replaced and included in the area development project or if it was of such quality that it could last for many more years.
The municipality sought a party that could perform an accurate and comprehensive condition assessment while also pinpointing the exact location of the pipeline. “I knew there were risky pipelines that needed to be inspected or possibly even replaced. So, we started looking for a party that could provide a complete and accurate condition assessment and map the exact location of the pressure pipeline,” says Arthur Nijhof, senior quality manager of sewerage at the Municipality of Nijmegen. “Previously, we tested a smart ball from a non-Dutch market party; it worked fine, but since we wanted to gather more data at once, it did not meet our expectations. Ultimately, we chose an inspection with the Acquarius from Acquaint. This tool can perform the most complete and detailed inspection and is suitable for all types of pipe materials.”
The Acquarius is a PIG (Pipeline Inspection Gauge) applicable to (risky) pipeline works of any material, including asbestos-cement. Acquaint has inspected more kilometers of asbestos-cement than any other material, giving them unique expertise. The Acquarius uses ultrasonic waves to measure various pipeline properties, such as wall thickness, axial deformation, joint condition (joint width and angular deflections), leaching, and leaks. With its patent on measuring the leaching of AC pipeline material, Acquaint can also determine which part of the wall thickness is still healthy and which part is weakened by leaching. Additionally, the Acquarius is equipped with various other sensors for precise XYZ mapping. These features make the use of the Acquarius the most logical and best choice for measuring this pipeline.
Thanks to the Municipality of Nijmegen, an educational demo day was organized during the launch of the Acquarius in the pipeline to be inspected. Several other municipalities and water boards were invited to witness the launch. The day began with an explanation of how Acquaint conducts an inspection with the Acquarius. This was followed by a live viewing of the Acquarius launch. After the launch, several inspiring presentations were given by Jan van Doorn (GMB), Peter Brink (Brink sewer management), Michiel Swaving Dijkstra, Max Lhoest (Sweco), and Acquaint’s own Erik Driessen. “The day proved to be incredibly educational and valuable. There was plenty of networking, and it was a great opportunity for municipalities and water boards to see how such an inspection actually works,” says Driessen.
After the inspection and processing of the collected data, the report with the outcomes was delivered. Acquaint presented the report, and the municipality gained access to Acquaint’s Inline Pipeline Inspection Dashboard. This dashboard provides the municipality with a clear overview of the condition of the measured pipeline. Nijhof says: “Because the stress condition norms of the soil on the pipeline are significantly exceeded, it appears that the pipe sections are under unacceptable stress conditions. This lowers the remaining lifespan, resulting in a worse situation than expected.” The inspection data, combined with a remaining lifespan calculation established by another company based on the data, showed that the section of the pipeline running under a busy road urgently needs replacement. The above strength calculations are based on theoretical material strength. “To make the calculations more accurate, a core sample (a test piece) of the pipeline needs to be taken. Laboratory testing can then establish the material strength used for validated stress calculations of the entire route. The condition measurements by Acquaint, together with remaining lifespan calculations based on strength measurements of an actual test sample, ultimately provide the most accurate condition of the pipeline and the most reliable basis for a replacement decision,” says Nijhof.
The cooperation between the two parties went very smoothly. The municipality indicates that they would recommend Acquaint to other parties and hope that new inspections with Acquaint will be conducted in the future. “There was a pleasant, collaborative relationship,” says Nijhof. “Acquaint’s working method contributes to peace of mind during such a project. The company performs its tasks excellently.” The cooperation with the contracting company GMB also went well. “Both companies have the same ‘drive’: proactive, solution-oriented, and hands-on. What needs to be done is done well,” says Nijhof. Although part of the pipeline was in worse condition than hoped, the municipality is very satisfied with the overall inspection by Acquaint. There was a good transfer of the report and clear results of the inspection. “We were provided with a complete overview, and the report contained many useful explanations. Furthermore, we were able to use the Inline Pipeline Inspection Dashboard internally to present the inspection results,” says Nijhof.