Basically, the operator of a wastewater heat extraction plant only needs the permission of the sewer network operator. The sewer network operator decides whether a system for extracting energy from wastewater can be installed in a particular sewer or not. The deciding factor for the sewer network operator, as the party with a sovereign responsibility, is that the sewer operation is not restricted in any way by the use of the wastewater for energy. This is precisely what we can ensure with our system, the Therm-Liner. As a company that has been working in sewer construction for five decades, we are well acquainted with the requirements inside the sewer. Before a plant is commissioned, all the parameters, such as the length of use, the basic technical conditions and the usage fee to be paid, are defined in a usage agreement. We are happy to provide templates for usage agreements of this type. There is no increased cleaning, maintenance or monitoring work for the sewer network operator in the sewer section used. In addition: The modules and connecting pipes are operated with pure tap water, and only run with a water-glycol mix in a few exceptional cases. This also simplifies the approval phase.