Waste to biofuel through hydrothermal carbonization

In this paper, the potentialities for energy purposes of “off-specification compost” (EWC 19.05.03) are studied. This is a residual byproduct from the treatment of the organic fraction of the municipal solid wastes that is not usable as soil improver according to the current Italian law. Hydrothermal carbonization is here evaluated as a candidate for the recovery of this residual fraction and for its transformation into an energetically exploitable material. For this purpose, the performances of the process were studied at different conditions of temperature and residence time, and analyses on the solid and the gaseous phases were executed. Considerations about the applicability of the process at real scale are presented at the end of the paper.