The utilization of wastewater heat is increasingly becoming the focus of sustainable energy supply. As a locally available heat source, it offers a wide range of possibilities for supplying buildings, neighborhoods, and entire supply areas with heat in an efficient and climate-friendly manner.

The heat can be extracted from the sewer network or at the outlet of the wastewater treatment plant and made usable for heating purposes via heat pumps. Especially in winter, when heating demand is highest, wastewater has relatively high temperatures in the favorable range of 10 °C to 15 °C, which is higher than other heat sources such as air and near-surface soil and enables more efficient heat pump operation. Various technical systems are available for gravity or pressure sewage pipes, as well as heat exchangers arranged outside the sewer in a bypass, so that solutions adapted to local conditions are possible.

The potential for wastewater heat utilization is far from being exhausted. Experts estimate that 5 to 10 percent of the heat demand of buildings can be covered by heat from wastewater.  The use of heat from sewage treatment plant effluent will also play an important role in the future, as the usable heat potential is particularly high there due to the high volume flow and the large achievable temperature difference.

Numerous projects implemented in practice show that wastewater heat utilization is not only technically proven, but can also be economically attractive.