The continuous HTD process is a hydrothermal treatment that is carried out on dehydrated sewage sludge at a temperature of 215 ° C at 20 bar.

The process is aimed at solubilizing the EPS (extracellular polymeric substances) of the sludge in order to increase its de-grading to over 70% of dry matter. The solid material obtained is considered an artificial lignite, while the liquid obtained from the filtration has a sufficient energy power to sustain the heat of the whole process.

The HTD process is a winner in terms of energy compared to drying with the same dry matter achieved.