Abstract: A system for the combustion of moist ligneous and other wastes, such as sawdust and compacted household rubbish in order to generate heat. The system includes a crusher-extractor to divide the waste matter entrained in an air stream to produce a fuel mixture that is fed into one input of an exchanger-separator whose output supplies a pyrolytic burner coupled to a boiler. The hot fumes from the boiler are fed back into the other input of the exchanger-separator which serves to mix fresh divided waste with residue or unburned waste extracted from the fumes, and to separate the waste material to be consumed in the burner from the hot gas and moisture.