Independent study shows trenchless sewer rehabilitation using GRP-UV liners to perform best among commonly used methods.
Trenchless sewer rehabilitation with UV-curable GRP liners has the lowest CO2 emissions of all repair methods for sewer pipes. This is the result of a study by the Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT.
The organisation for applied research has compared three common methods used to rehabilitate sewer systems in Germany. These were the use of concrete pipes in open trench construction, trenchless rehabilitation with temperature-curing synthetic fibre pipe liners, and UV light-curing pipe liners made of glass fibre reinforced plastic (GRP). The project was commissioned by RelineEurope GmbH and IMPREG GmbH, both leading manufacturers of UV GRP liners.
Life-cycle assessment reveals significant differences
The study centred on a life-cycle assessment (LCA) that the Oberhausen-based Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT conducted in accordance with ISO 14040. This internationally standardised procedure analyses products and their impact on the environment and examines factors such as carbon footprint along the entire value chain – from raw material procurement through to production, product application, and ultimately disposal.
The study analysed sewer pipes in three common diameters:
DN 400, DN 800, and DN 1200 and the researchers drew the following conclusions. Assuming a sewer length of 50 metres, temperature-cured synthetic fibre pipe relining releases between 43% and 64% more carbon dioxide than a UV GRP relining, while the carbon footprint of concrete pipe installation is between 132% and 339% larger than the UV light-cured GRP pipe liner method. Curing synthetic-fibre pipe liners using heat or steam is particularly resource-intensive. In turn, the colossal carbon footprint of concrete pipes is due to a combination of the carbon-intensive production process, high transport costs, and the need for open trench excavation, which requires the use of heavy machinery for the earthworks and final asphalting. All these negative factors do not come into play as part of UV GRP relining-based rehabilitations.
IMPREG and RELINE see themselves confirmed
“The message to local authorities, planning offices, and renovation companies is clear,” says Karsten Mueller, CEO of the IMPREG Group. “UV light-cured GRP lining is still the most environmentally friendly and cost-efficient method of bringing damaged sewers back into full working order for 50 years or more. This has now also been confirmed by independent scientific research. UV GRP technology makes a significant contribution to protecting our water cycle and guarding it against harmful influences, which is particularly important in view of climate change. If the industry in Europe were to switch as one from temperature curing to UV curing, the savings would be equivalent to the total annual emissions of Slovakia, and a switch from concrete pipes to UV-cured GRP liners would actually see a reduction equivalent to Spain’s annual emissions.”
“That two market competitors are working together to have the sustainability of UV technology validated on behalf of the entire industry is a powerful signal.
The results of the scientific analysis have also confirmed the views of RELINE’s Managing Director, Marc Stiebing. “That two market competitors are working together to have the sustainability of UV technology validated on behalf of the entire industry is a powerful signal,” he adds. “The German sewer network is in a critical state. Exfiltration and infiltration are damaging the environment and placing a massive strain on sewage treatment plants. Around 6,000km of pipes – or around one percent of the entire network – have to be repaired across Germany every year. The sector will only be able to overcome this challenge by working together. The findings of Fraunhofer’s study will further enhance the competitiveness of UV-cured GRP liners on the market. Thanks to its outstanding carbon footprint, UV GRP relining provides a future-oriented solution for sustainable water management, and therefore makes an active contribution to protecting the environment and conserving our resources.”
