The calorimetric cells of a Setaram BT 2.15 flux calorimeter have been modified, in order to measure the heat production associated with microbial growth, with a continuous flow of gas and liquid through the sample. Good conditions for the growth of the microorganisms present in a polluted soil were determined and the possibility of the bioremediation examined. It was shown that the biodegradation of hydrocarbons adsorbed for a long time in the soil is a very slow process difficult to study with calorimetry. On the contrary, sodium succinate and different C₁₄ hydrocarbons were easily biodegradated, producing a large quantity of heat.