Geothermal Science





The very first application of geothermal science in Saint-Ghislain began in Autumn 1985. The exploitation primarily concerned a district heating system, more precisely a district heating system for schools and sports centres as well as community housing located in Saint-Ghislain.
How does the district heating system work?

We shall follow the journey of geothermal water. This is drawn from the well in Saint-Ghislain in line with requirements and is channelled towards the central heating factory where it passes through the battery of heat exchangers so as to transfer its heat to the water in the network of district heaters. During this operation, the temperature of the geothermal water drops considerably, from 70° to 40°.

Partially stripped of its calorific qualities, the geothermal water leaves the heating factory and is channelled firstly towards the horticultural complex, and subsequently towards the pre-heating of sewage sludge at the waste water purification plant in Wasmuël. It is then successively used for two other heating operations which we shall discuss later and its temperature drops to 30°, allowing it to be discharged into the Haine whilst respecting the requirements concerning the protection of waterways.

In addition to the temperature exchangers, the heating factory is equipped with classic heaters which can provide additional heat or, where appropriate, heat the entire network of heating water.


Three uses in series are implemented:
  • A district heating system allowing for the geothermal water used to return after use to a temperature up to 40°.
  • This same water subsequently being used for heating horticultural greenhouses by extracting the energy available at 40° at 35°.
  • This same water finally being used for pre-heating of sewage sludge in the digester at the waste water purification plant in Wasmuël which shall use part of the energy available between 35° and 40°.


This use in series of warm water – of given quality and temperature – first of all enables maximal geothermal contribution for district heating, and subsequently for the best possible use of the available potential of this geothermal water and, finally, enables requirements to be met in terms of environmental protection.

Learn more : www.energie.wallonie.be

Responsible for this website : town of Saint-Ghislain
City Council : rue de Chièvres, 17 – 7333 Saint-Ghislain (Tertre)
Phone : + 32 (0)65 76 19 00 – Fax : + 32 (0)65 76 20 00 – Mal : info@saint-ghislain.be