Ecological comparison of wastewater pipe rehabilitation with glass fiber liners compared to replacement with new concrete pipes in Germany

In Germany hundreds of thousands of kilometers of wastewater pipes will need to be modernized in the near future. Two upkeeping approaches are compared by using a cradle-to-grave life cycle assessment: trenchless rehabilitation with cured-in-place glass fiber liners versus open-trench replacement with concrete or reinforced concrete pipes. Due to the very long service life of over 50 years, estimates are made for end-of-life treatment. Thermal recycling in a cement plant is assumed optimal for the disposal of glass-fiber liners. However, the end-of-life treatment of the liners is of minor environmental importance compared to the installation efforts of concrete pipes. The analysis shows some environmental advantages for glass liners in the production stage but major advantages in the installation stage, depending on the actual installation conditions. Overall, the rehabilitation by liners shows obvious environmental advantages over the replacement of wastewater pipes.