Yes. Wastewater has an average temperature of 10 to 12 °C in winter and 17 to 20 °C in summer. This temperature represents thermal energy that can be used to heat buildings in winter and cool them in summer. Wastewater is a completely underestimated, renewable energy source that can make a significant contribution to climate protection in the heating market. In addition: The level of wastewater can be calculated and forecast precisely over decades, which means that the use of wastewater for energy offers a high degree of reliability. What is particularly attractive is the fact that the temperature of wastewater recovers again very quickly even after large quantities of energy have been extracted. This is due firstly to the inflow of new wastewater into the sewers and secondly to the constant uptake of ambient warmth from the ground. It is therefore possible to install a large number of plants to extract energy from wastewater in a sewer network. The only thing that is important is that the plants must be a certain distance apart. The rule of thumb is: After a wastewater heat recovery plant, a “recovery line” around two to three times the length of the plant itself should be incorporated. If a wastewater energy recovery plant is 100 m long, then another plant can be installed around 200 to 300 m afterwards.
