Two records and a major project
Most people remain unaware of what goes on underground. Society only becomes conscious of the issue when problems arise. After all, functioning sewers are essential. They are needed for an intact infrastructure and to protect health.
With the project in the city of Bruges in Belgium, IMPREG GmbH has once again confirmed its status as a pioneer and specialist for large profiles. Together with IMPREG GmbH’s long-standing customers, Kumpen Renovatietechnieken and Smet Group, several DN 1400 – DN 2000 sewers belonging to the client Aquafin NV in Belgium were renovated in an extremely complex large-scale project.
Consulting expertise
A team of experts from IMPREG GmbH provided consulting and implementation support throughout the entire project, from planning to final acceptance. This made it possible to check feasibility right from the start and plan implementation at a professional level.
High complexity requires precise preparation
Over many years, high levels of biogenic sulphuric acid and aggressive dirty water had corroded the concrete pipes to such an extent that the steel reinforcement was already visible in some places. Action had to be taken quickly. The operator of the Aquafin NV sewage treatment plant opted for renovation using GRP liners with UV technology.
In order to carry out the rehabilitation on the soft and partly sandy subsoil, a construction road several hundred metres long had to be laid out with steel plates. Only then was it possible for trucks and construction machinery to drive on it. In addition, extensive wastewater diversion was necessary. This concept was designed not only for dry weather drainage for the 120,000 inhabitants of Bruges, but also for rainy weather events.
In order to access the sewers located approximately 7 m to 9 m below the surface and enable the large-profile liners to be inserted, cast-in-place concrete shafts were constructed using pile foundations, as it was not possible to lower the groundwater level.
For the installation, the construction project was divided into several renovation sections with pipe diameters ranging from DN 1400 to DN 2000 and renovation lengths of up to 200 metres.
The record – 45.2 tonnes of IMPREGLiner and the first DN 2000 in Belgium
The largest and heaviest IMPREGLiner DN 2000 in the Bruges project weighed in at an enormous 45.2 tonnes with a length of 159 metres and a wall thickness of 22.1 mm, making it the heaviest GRP pipe liner ever produced in the history of IMPREG GmbH. Together with its reusable transport crate, which was specially manufactured for this project, and special cooling, the record-breaking liner even reached a total weight of an impressive 56 tonnes. IMPREG GmbH set a second record in Bruges with the first GRP pipe liner DN 2000 ever installed in this size.
Power for pulling in the GRP CIPP liner and curing a wall thickness of 22.1 mm
Both the installation team and the machines worked extremely hard on the record-breaking UV liner. Around 30 men were on site to pull 45.2 tonnes into a sewer. 
The liner was pulled out of the box using an installation aid with a folding device. Next, a pulling packer specially designed and manufactured for this application was tied onto the liner and then pulled into the sewer. Thanks to jointly coordinated scheduling, all work was completed within the planned time frame.
Curing GRP CIPP liners of this size requires sufficient UV power. A ProKASRO Power UV system with three jumbo cores and an output of 3 x 6 x 2,000 watts was used. Due to the wall thickness of 22.1 mm, curing cannot be guaranteed by UV radiation alone. For this reason, a peroxide was added to the resin mixture as a reaction accelerator. This releases additional energy as a result of the exothermic reaction caused by UV curing, ensuring that the curing process covers the entire wall thickness.
‘The combination of different perspectives, the highest level of expertise in theory and practice, and the creativity of the manufacturer IMPREG GmbH for temperature controlled transport, characterised by mutual trust and the utmost respect, has led to this success,’ says Gert-Jan Merkx, CEO of Kumpen Renovatietechnieken.
IMPREG – your supplier of choice
The following factors were decisive in choosing IMPREG GmbH and the IMPREGLiner:
– Global references and many years of expertise in the rehabilitation of large profiles larger than DN 1200
– Competence in planning and technical know-how of the IMPREG team based on a long-standing partnership and characterised by transparent and appreciative communication on an equal footing
– Properties of the IMPREGLiner that ensure safe handling on the construction site and durability in the sewer
– Lean production and just-in-time delivery to the construction site
‘The success of this measure is the result of cooperation between all parties involved at the highest level from start to finish. Everything fell into place in all areas – this fills me and the entire IMPREG GmbH with great pride. Further projects of this magnitude are already in the planning stage – both in Europe and in the USA,’ says Guido Wey, GM of IMPREG GmbH.
