Thermal use of wastewater – Policy instruments for initialization and potential operating models / Thermische Nutzung von Abwasser – Instrumente zur Verbreitung und mögliche Betreibermodelle

The heat content of wastewater presents a great but still widely unused potential for energy supply. The thermal energy recovered through heat exchangers and heat pumps can be used for the heating (and cooling) of buildings and even for hot water production. At the moment, at least about 500 installations are operated on a global scale, and most experiences are available in Switzerland. In Austria, some wastewater heat recovery systems are also already under operation, for instance in Amstetten and in Weiz. However, due to the lack of superordinate strategies for planning, implementing, and operating wastewater heat recovery systems on federal and provincial level, the Austrian installations are primarily the result of personal initiatives of local stakeholders. This paper gives a general overview of different policy instruments for initializing and further promoting wastewater heat recovery as well as potential operating models for related heat supply systems and conducts a related comparison with the current Austrian situation. The information gained can serve as an input for the development of an initialization program for wastewater heat recovery on Austrian national level.