Risk concerning rehabilitation of closed sewers wth internal diameter bigger than 1 m
In the last few years there have been executed some substantial rehabilitation project that concerned sewers with diameters bigger then 1 m. Those kind of sewers are used not only for drainage, but also for the retention. That is why most valuable rehabilitation solutions in this case are those methods which do not result in a pipe diameter reduction – and that would be the CIPP or construction chemicals usage. Both of the solutions are risky and demand thoroughness.

dr inż. Andrzej Kolonko, Wroclaw University of Technology
Wrocław University of Technology graduate. He specializes in the urban infrastructure and actively promotes modern trenchless technologies. For many years he has been the organizing secretary of the international science and technology conference. "Underground infrastructure of cities". Wrocław University of Technology academic teacher and researcher. He cooperates with foreign scientific centres and companies. He is the author and co-author of numerous publications in national and international magazines including: "Constructions of Sewerage Ducts", "Microtunneling" and "Renovation of water pipes by cementing". In addition, he is the author and the co-author of three patents and a utility model.