We need to stop looking at wastewater as waste. Wastewater is a sustainable, cheap and readily available form of energy, which can be used to produce e.g. district heating? The wastewater temperature varies throughout the year. It is, however, typically warmer than both sea water and air making it an obvious choice of heat source for a heat pump system.

The wastewater is cooled as the energy is extracted. The low-temperature energy from the wastewater is subsequently converted in the electric heat pump, where the energy is compressed into remote energy at normal flow temperature.

Security of supply and environment-friendly solution

There are several advantages of recycling wastewater. On the one hand, it is positive for district heating consumers, as the relatively high temperature of wastewater ensures a more stable and sustainable energy supply. Likewise, it is positive for the aquatic environment that the outlet temperature of the treated wastewater is decreased and is hence closer to the temperature of the aquatic environment in which it is discharged.

A heat pump plant that utilizes the energy from wastewater as a heat source for the production of district heating is a good example of efficient sector coupling.

Prior to establishing a wastewater heat pump system, Aalborg CSP prepares thorough studies of the area, in order for all known challenges to be taken into account in regard to the final installation.


Andreas Zourellis
VP Sales - International
District heating / industrial solar technologies
Phone: +45 50 30 00 25 
E-mail: azo@aalborgcsp.com