Pyrolysis or hydrothermal carbonisation for anaerobic-digested sewage sludge? A comparison of pyrochar and hydrochar structure and stability: data

Thermochemical conversion of sewage sludge was proven as a useful method for waste management. HTC showed the greatest potential to produce a material with higher adsorption capacity (100 cm3 /g for H180-4) but all chars should be subjected to an activation process to be able to compete with other kinds of feedstocks. The reduction of the H:C and O:C from the original SS after the treatments indicated a greater carbonisation degree, but a general reduction of the high heating value (HHV) from 17.94 MJ kg−1 in SS to (14.93 MJ kg−1 ). The torrefied char and hydrochars could be an attractive option to reduce energy of the process and drying stage in the case of HTC.